4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #include <linux/kernel.h>
19 #include <linux/device.h>
20 #include <linux/init.h>
21 #include <linux/cache.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/dmaengine.h>
24 #include <linux/mutex.h>
25 #include <linux/of_device.h>
26 #include <linux/of_irq.h>
27 #include <linux/clk/clk-conf.h>
28 #include <linux/slab.h>
29 #include <linux/mod_devicetable.h>
30 #include <linux/spi/spi.h>
31 #include <linux/of_gpio.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/pm_domain.h>
34 #include <linux/export.h>
35 #include <linux/sched/rt.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
38 #include <linux/ioport.h>
39 #include <linux/acpi.h>
41 #define CREATE_TRACE_POINTS
42 #include <trace/events/spi.h>
44 static void spidev_release(struct device *dev)
46 struct spi_device *spi = to_spi_device(dev);
48 /* spi masters may cleanup for released devices */
49 if (spi->master->cleanup)
50 spi->master->cleanup(spi);
52 spi_master_put(spi->master);
57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
59 const struct spi_device *spi = to_spi_device(dev);
62 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
68 static DEVICE_ATTR_RO(modalias);
70 #define SPI_STATISTICS_ATTRS(field, file) \
71 static ssize_t spi_master_##field##_show(struct device *dev, \
72 struct device_attribute *attr, \
75 struct spi_master *master = container_of(dev, \
76 struct spi_master, dev); \
77 return spi_statistics_##field##_show(&master->statistics, buf); \
79 static struct device_attribute dev_attr_spi_master_##field = { \
80 .attr = { .name = file, .mode = S_IRUGO }, \
81 .show = spi_master_##field##_show, \
83 static ssize_t spi_device_##field##_show(struct device *dev, \
84 struct device_attribute *attr, \
87 struct spi_device *spi = to_spi_device(dev); \
88 return spi_statistics_##field##_show(&spi->statistics, buf); \
90 static struct device_attribute dev_attr_spi_device_##field = { \
91 .attr = { .name = file, .mode = S_IRUGO }, \
92 .show = spi_device_##field##_show, \
95 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
96 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
99 unsigned long flags; \
101 spin_lock_irqsave(&stat->lock, flags); \
102 len = sprintf(buf, format_string, stat->field); \
103 spin_unlock_irqrestore(&stat->lock, flags); \
106 SPI_STATISTICS_ATTRS(name, file)
108 #define SPI_STATISTICS_SHOW(field, format_string) \
109 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
110 field, format_string)
112 SPI_STATISTICS_SHOW(messages, "%lu");
113 SPI_STATISTICS_SHOW(transfers, "%lu");
114 SPI_STATISTICS_SHOW(errors, "%lu");
115 SPI_STATISTICS_SHOW(timedout, "%lu");
117 SPI_STATISTICS_SHOW(spi_sync, "%lu");
118 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
119 SPI_STATISTICS_SHOW(spi_async, "%lu");
121 SPI_STATISTICS_SHOW(bytes, "%llu");
122 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
123 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
125 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
126 SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
127 "transfer_bytes_histo_" number, \
128 transfer_bytes_histo[index], "%lu")
129 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
147 static struct attribute *spi_dev_attrs[] = {
148 &dev_attr_modalias.attr,
152 static const struct attribute_group spi_dev_group = {
153 .attrs = spi_dev_attrs,
156 static struct attribute *spi_device_statistics_attrs[] = {
157 &dev_attr_spi_device_messages.attr,
158 &dev_attr_spi_device_transfers.attr,
159 &dev_attr_spi_device_errors.attr,
160 &dev_attr_spi_device_timedout.attr,
161 &dev_attr_spi_device_spi_sync.attr,
162 &dev_attr_spi_device_spi_sync_immediate.attr,
163 &dev_attr_spi_device_spi_async.attr,
164 &dev_attr_spi_device_bytes.attr,
165 &dev_attr_spi_device_bytes_rx.attr,
166 &dev_attr_spi_device_bytes_tx.attr,
167 &dev_attr_spi_device_transfer_bytes_histo0.attr,
168 &dev_attr_spi_device_transfer_bytes_histo1.attr,
169 &dev_attr_spi_device_transfer_bytes_histo2.attr,
170 &dev_attr_spi_device_transfer_bytes_histo3.attr,
171 &dev_attr_spi_device_transfer_bytes_histo4.attr,
172 &dev_attr_spi_device_transfer_bytes_histo5.attr,
173 &dev_attr_spi_device_transfer_bytes_histo6.attr,
174 &dev_attr_spi_device_transfer_bytes_histo7.attr,
175 &dev_attr_spi_device_transfer_bytes_histo8.attr,
176 &dev_attr_spi_device_transfer_bytes_histo9.attr,
177 &dev_attr_spi_device_transfer_bytes_histo10.attr,
178 &dev_attr_spi_device_transfer_bytes_histo11.attr,
179 &dev_attr_spi_device_transfer_bytes_histo12.attr,
180 &dev_attr_spi_device_transfer_bytes_histo13.attr,
181 &dev_attr_spi_device_transfer_bytes_histo14.attr,
182 &dev_attr_spi_device_transfer_bytes_histo15.attr,
183 &dev_attr_spi_device_transfer_bytes_histo16.attr,
187 static const struct attribute_group spi_device_statistics_group = {
188 .name = "statistics",
189 .attrs = spi_device_statistics_attrs,
192 static const struct attribute_group *spi_dev_groups[] = {
194 &spi_device_statistics_group,
198 static struct attribute *spi_master_statistics_attrs[] = {
199 &dev_attr_spi_master_messages.attr,
200 &dev_attr_spi_master_transfers.attr,
201 &dev_attr_spi_master_errors.attr,
202 &dev_attr_spi_master_timedout.attr,
203 &dev_attr_spi_master_spi_sync.attr,
204 &dev_attr_spi_master_spi_sync_immediate.attr,
205 &dev_attr_spi_master_spi_async.attr,
206 &dev_attr_spi_master_bytes.attr,
207 &dev_attr_spi_master_bytes_rx.attr,
208 &dev_attr_spi_master_bytes_tx.attr,
209 &dev_attr_spi_master_transfer_bytes_histo0.attr,
210 &dev_attr_spi_master_transfer_bytes_histo1.attr,
211 &dev_attr_spi_master_transfer_bytes_histo2.attr,
212 &dev_attr_spi_master_transfer_bytes_histo3.attr,
213 &dev_attr_spi_master_transfer_bytes_histo4.attr,
214 &dev_attr_spi_master_transfer_bytes_histo5.attr,
215 &dev_attr_spi_master_transfer_bytes_histo6.attr,
216 &dev_attr_spi_master_transfer_bytes_histo7.attr,
217 &dev_attr_spi_master_transfer_bytes_histo8.attr,
218 &dev_attr_spi_master_transfer_bytes_histo9.attr,
219 &dev_attr_spi_master_transfer_bytes_histo10.attr,
220 &dev_attr_spi_master_transfer_bytes_histo11.attr,
221 &dev_attr_spi_master_transfer_bytes_histo12.attr,
222 &dev_attr_spi_master_transfer_bytes_histo13.attr,
223 &dev_attr_spi_master_transfer_bytes_histo14.attr,
224 &dev_attr_spi_master_transfer_bytes_histo15.attr,
225 &dev_attr_spi_master_transfer_bytes_histo16.attr,
229 static const struct attribute_group spi_master_statistics_group = {
230 .name = "statistics",
231 .attrs = spi_master_statistics_attrs,
234 static const struct attribute_group *spi_master_groups[] = {
235 &spi_master_statistics_group,
239 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
240 struct spi_transfer *xfer,
241 struct spi_master *master)
244 int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
249 spin_lock_irqsave(&stats->lock, flags);
252 stats->transfer_bytes_histo[l2len]++;
254 stats->bytes += xfer->len;
255 if ((xfer->tx_buf) &&
256 (xfer->tx_buf != master->dummy_tx))
257 stats->bytes_tx += xfer->len;
258 if ((xfer->rx_buf) &&
259 (xfer->rx_buf != master->dummy_rx))
260 stats->bytes_rx += xfer->len;
262 spin_unlock_irqrestore(&stats->lock, flags);
264 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
266 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
267 * and the sysfs version makes coldplug work too.
270 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
271 const struct spi_device *sdev)
273 while (id->name[0]) {
274 if (!strcmp(sdev->modalias, id->name))
281 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
283 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
285 return spi_match_id(sdrv->id_table, sdev);
287 EXPORT_SYMBOL_GPL(spi_get_device_id);
289 static int spi_match_device(struct device *dev, struct device_driver *drv)
291 const struct spi_device *spi = to_spi_device(dev);
292 const struct spi_driver *sdrv = to_spi_driver(drv);
294 /* Attempt an OF style match */
295 if (of_driver_match_device(dev, drv))
299 if (acpi_driver_match_device(dev, drv))
303 return !!spi_match_id(sdrv->id_table, spi);
305 return strcmp(spi->modalias, drv->name) == 0;
308 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
310 const struct spi_device *spi = to_spi_device(dev);
313 rc = acpi_device_uevent_modalias(dev, env);
317 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
321 struct bus_type spi_bus_type = {
323 .dev_groups = spi_dev_groups,
324 .match = spi_match_device,
325 .uevent = spi_uevent,
327 EXPORT_SYMBOL_GPL(spi_bus_type);
330 static int spi_drv_probe(struct device *dev)
332 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
333 struct spi_device *spi = to_spi_device(dev);
336 ret = of_clk_set_defaults(dev->of_node, false);
341 spi->irq = of_irq_get(dev->of_node, 0);
342 if (spi->irq == -EPROBE_DEFER)
343 return -EPROBE_DEFER;
348 ret = dev_pm_domain_attach(dev, true);
349 if (ret != -EPROBE_DEFER) {
350 ret = sdrv->probe(spi);
352 dev_pm_domain_detach(dev, true);
358 static int spi_drv_remove(struct device *dev)
360 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
363 ret = sdrv->remove(to_spi_device(dev));
364 dev_pm_domain_detach(dev, true);
369 static void spi_drv_shutdown(struct device *dev)
371 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
373 sdrv->shutdown(to_spi_device(dev));
377 * __spi_register_driver - register a SPI driver
378 * @owner: owner module of the driver to register
379 * @sdrv: the driver to register
382 * Return: zero on success, else a negative error code.
384 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
386 sdrv->driver.owner = owner;
387 sdrv->driver.bus = &spi_bus_type;
389 sdrv->driver.probe = spi_drv_probe;
391 sdrv->driver.remove = spi_drv_remove;
393 sdrv->driver.shutdown = spi_drv_shutdown;
394 return driver_register(&sdrv->driver);
396 EXPORT_SYMBOL_GPL(__spi_register_driver);
398 /*-------------------------------------------------------------------------*/
400 /* SPI devices should normally not be created by SPI device drivers; that
401 * would make them board-specific. Similarly with SPI master drivers.
402 * Device registration normally goes into like arch/.../mach.../board-YYY.c
403 * with other readonly (flashable) information about mainboard devices.
407 struct list_head list;
408 struct spi_board_info board_info;
411 static LIST_HEAD(board_list);
412 static LIST_HEAD(spi_master_list);
415 * Used to protect add/del opertion for board_info list and
416 * spi_master list, and their matching process
418 static DEFINE_MUTEX(board_lock);
421 * spi_alloc_device - Allocate a new SPI device
422 * @master: Controller to which device is connected
425 * Allows a driver to allocate and initialize a spi_device without
426 * registering it immediately. This allows a driver to directly
427 * fill the spi_device with device parameters before calling
428 * spi_add_device() on it.
430 * Caller is responsible to call spi_add_device() on the returned
431 * spi_device structure to add it to the SPI master. If the caller
432 * needs to discard the spi_device without adding it, then it should
433 * call spi_dev_put() on it.
435 * Return: a pointer to the new device, or NULL.
437 struct spi_device *spi_alloc_device(struct spi_master *master)
439 struct spi_device *spi;
441 if (!spi_master_get(master))
444 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
446 spi_master_put(master);
450 spi->master = master;
451 spi->dev.parent = &master->dev;
452 spi->dev.bus = &spi_bus_type;
453 spi->dev.release = spidev_release;
454 spi->cs_gpio = -ENOENT;
456 spin_lock_init(&spi->statistics.lock);
458 device_initialize(&spi->dev);
461 EXPORT_SYMBOL_GPL(spi_alloc_device);
463 static void spi_dev_set_name(struct spi_device *spi)
465 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
468 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
472 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
476 static int spi_dev_check(struct device *dev, void *data)
478 struct spi_device *spi = to_spi_device(dev);
479 struct spi_device *new_spi = data;
481 if (spi->master == new_spi->master &&
482 spi->chip_select == new_spi->chip_select)
488 * spi_add_device - Add spi_device allocated with spi_alloc_device
489 * @spi: spi_device to register
491 * Companion function to spi_alloc_device. Devices allocated with
492 * spi_alloc_device can be added onto the spi bus with this function.
494 * Return: 0 on success; negative errno on failure
496 int spi_add_device(struct spi_device *spi)
498 static DEFINE_MUTEX(spi_add_lock);
499 struct spi_master *master = spi->master;
500 struct device *dev = master->dev.parent;
503 /* Chipselects are numbered 0..max; validate. */
504 if (spi->chip_select >= master->num_chipselect) {
505 dev_err(dev, "cs%d >= max %d\n",
507 master->num_chipselect);
511 /* Set the bus ID string */
512 spi_dev_set_name(spi);
514 /* We need to make sure there's no other device with this
515 * chipselect **BEFORE** we call setup(), else we'll trash
516 * its configuration. Lock against concurrent add() calls.
518 mutex_lock(&spi_add_lock);
520 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
522 dev_err(dev, "chipselect %d already in use\n",
527 if (master->cs_gpios)
528 spi->cs_gpio = master->cs_gpios[spi->chip_select];
530 /* Drivers may modify this initial i/o setup, but will
531 * normally rely on the device being setup. Devices
532 * using SPI_CS_HIGH can't coexist well otherwise...
534 status = spi_setup(spi);
536 dev_err(dev, "can't setup %s, status %d\n",
537 dev_name(&spi->dev), status);
541 /* Device may be bound to an active driver when this returns */
542 status = device_add(&spi->dev);
544 dev_err(dev, "can't add %s, status %d\n",
545 dev_name(&spi->dev), status);
547 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
550 mutex_unlock(&spi_add_lock);
553 EXPORT_SYMBOL_GPL(spi_add_device);
556 * spi_new_device - instantiate one new SPI device
557 * @master: Controller to which device is connected
558 * @chip: Describes the SPI device
561 * On typical mainboards, this is purely internal; and it's not needed
562 * after board init creates the hard-wired devices. Some development
563 * platforms may not be able to use spi_register_board_info though, and
564 * this is exported so that for example a USB or parport based adapter
565 * driver could add devices (which it would learn about out-of-band).
567 * Return: the new device, or NULL.
569 struct spi_device *spi_new_device(struct spi_master *master,
570 struct spi_board_info *chip)
572 struct spi_device *proxy;
575 /* NOTE: caller did any chip->bus_num checks necessary.
577 * Also, unless we change the return value convention to use
578 * error-or-pointer (not NULL-or-pointer), troubleshootability
579 * suggests syslogged diagnostics are best here (ugh).
582 proxy = spi_alloc_device(master);
586 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
588 proxy->chip_select = chip->chip_select;
589 proxy->max_speed_hz = chip->max_speed_hz;
590 proxy->mode = chip->mode;
591 proxy->irq = chip->irq;
592 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
593 proxy->dev.platform_data = (void *) chip->platform_data;
594 proxy->controller_data = chip->controller_data;
595 proxy->controller_state = NULL;
597 status = spi_add_device(proxy);
605 EXPORT_SYMBOL_GPL(spi_new_device);
608 * spi_unregister_device - unregister a single SPI device
609 * @spi: spi_device to unregister
611 * Start making the passed SPI device vanish. Normally this would be handled
612 * by spi_unregister_master().
614 void spi_unregister_device(struct spi_device *spi)
619 if (spi->dev.of_node)
620 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
621 device_unregister(&spi->dev);
623 EXPORT_SYMBOL_GPL(spi_unregister_device);
625 static void spi_match_master_to_boardinfo(struct spi_master *master,
626 struct spi_board_info *bi)
628 struct spi_device *dev;
630 if (master->bus_num != bi->bus_num)
633 dev = spi_new_device(master, bi);
635 dev_err(master->dev.parent, "can't create new device for %s\n",
640 * spi_register_board_info - register SPI devices for a given board
641 * @info: array of chip descriptors
642 * @n: how many descriptors are provided
645 * Board-specific early init code calls this (probably during arch_initcall)
646 * with segments of the SPI device table. Any device nodes are created later,
647 * after the relevant parent SPI controller (bus_num) is defined. We keep
648 * this table of devices forever, so that reloading a controller driver will
649 * not make Linux forget about these hard-wired devices.
651 * Other code can also call this, e.g. a particular add-on board might provide
652 * SPI devices through its expansion connector, so code initializing that board
653 * would naturally declare its SPI devices.
655 * The board info passed can safely be __initdata ... but be careful of
656 * any embedded pointers (platform_data, etc), they're copied as-is.
658 * Return: zero on success, else a negative error code.
660 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
662 struct boardinfo *bi;
668 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
672 for (i = 0; i < n; i++, bi++, info++) {
673 struct spi_master *master;
675 memcpy(&bi->board_info, info, sizeof(*info));
676 mutex_lock(&board_lock);
677 list_add_tail(&bi->list, &board_list);
678 list_for_each_entry(master, &spi_master_list, list)
679 spi_match_master_to_boardinfo(master, &bi->board_info);
680 mutex_unlock(&board_lock);
686 /*-------------------------------------------------------------------------*/
688 static void spi_set_cs(struct spi_device *spi, bool enable)
690 if (spi->mode & SPI_CS_HIGH)
693 if (gpio_is_valid(spi->cs_gpio))
694 gpio_set_value(spi->cs_gpio, !enable);
695 else if (spi->master->set_cs)
696 spi->master->set_cs(spi, !enable);
699 #ifdef CONFIG_HAS_DMA
700 static int spi_map_buf(struct spi_master *master, struct device *dev,
701 struct sg_table *sgt, void *buf, size_t len,
702 enum dma_data_direction dir)
704 const bool vmalloced_buf = is_vmalloc_addr(buf);
707 struct page *vm_page;
713 desc_len = PAGE_SIZE;
714 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
716 desc_len = master->max_dma_len;
717 sgs = DIV_ROUND_UP(len, desc_len);
720 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
724 for (i = 0; i < sgs; i++) {
728 len, desc_len - offset_in_page(buf));
729 vm_page = vmalloc_to_page(buf);
734 sg_set_page(&sgt->sgl[i], vm_page,
735 min, offset_in_page(buf));
737 min = min_t(size_t, len, desc_len);
739 sg_set_buf(&sgt->sgl[i], sg_buf, min);
747 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
760 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
761 struct sg_table *sgt, enum dma_data_direction dir)
763 if (sgt->orig_nents) {
764 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
769 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
771 struct device *tx_dev, *rx_dev;
772 struct spi_transfer *xfer;
775 if (!master->can_dma)
779 tx_dev = master->dma_tx->device->dev;
781 tx_dev = &master->dev;
784 rx_dev = master->dma_rx->device->dev;
786 rx_dev = &master->dev;
788 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
789 if (!master->can_dma(master, msg->spi, xfer))
792 if (xfer->tx_buf != NULL) {
793 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
794 (void *)xfer->tx_buf, xfer->len,
800 if (xfer->rx_buf != NULL) {
801 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
802 xfer->rx_buf, xfer->len,
805 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
812 master->cur_msg_mapped = true;
817 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
819 struct spi_transfer *xfer;
820 struct device *tx_dev, *rx_dev;
822 if (!master->cur_msg_mapped || !master->can_dma)
826 tx_dev = master->dma_tx->device->dev;
828 tx_dev = &master->dev;
831 rx_dev = master->dma_rx->device->dev;
833 rx_dev = &master->dev;
835 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
836 if (!master->can_dma(master, msg->spi, xfer))
839 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
840 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
845 #else /* !CONFIG_HAS_DMA */
846 static inline int __spi_map_msg(struct spi_master *master,
847 struct spi_message *msg)
852 static inline int __spi_unmap_msg(struct spi_master *master,
853 struct spi_message *msg)
857 #endif /* !CONFIG_HAS_DMA */
859 static inline int spi_unmap_msg(struct spi_master *master,
860 struct spi_message *msg)
862 struct spi_transfer *xfer;
864 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
866 * Restore the original value of tx_buf or rx_buf if they are
869 if (xfer->tx_buf == master->dummy_tx)
871 if (xfer->rx_buf == master->dummy_rx)
875 return __spi_unmap_msg(master, msg);
878 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
880 struct spi_transfer *xfer;
882 unsigned int max_tx, max_rx;
884 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
888 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
889 if ((master->flags & SPI_MASTER_MUST_TX) &&
891 max_tx = max(xfer->len, max_tx);
892 if ((master->flags & SPI_MASTER_MUST_RX) &&
894 max_rx = max(xfer->len, max_rx);
898 tmp = krealloc(master->dummy_tx, max_tx,
899 GFP_KERNEL | GFP_DMA);
902 master->dummy_tx = tmp;
903 memset(tmp, 0, max_tx);
907 tmp = krealloc(master->dummy_rx, max_rx,
908 GFP_KERNEL | GFP_DMA);
911 master->dummy_rx = tmp;
914 if (max_tx || max_rx) {
915 list_for_each_entry(xfer, &msg->transfers,
918 xfer->tx_buf = master->dummy_tx;
920 xfer->rx_buf = master->dummy_rx;
925 return __spi_map_msg(master, msg);
929 * spi_transfer_one_message - Default implementation of transfer_one_message()
931 * This is a standard implementation of transfer_one_message() for
932 * drivers which impelment a transfer_one() operation. It provides
933 * standard handling of delays and chip select management.
935 static int spi_transfer_one_message(struct spi_master *master,
936 struct spi_message *msg)
938 struct spi_transfer *xfer;
939 bool keep_cs = false;
941 unsigned long ms = 1;
942 struct spi_statistics *statm = &master->statistics;
943 struct spi_statistics *stats = &msg->spi->statistics;
945 spi_set_cs(msg->spi, true);
947 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
948 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
950 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
951 trace_spi_transfer_start(msg, xfer);
953 spi_statistics_add_transfer_stats(statm, xfer, master);
954 spi_statistics_add_transfer_stats(stats, xfer, master);
956 if (xfer->tx_buf || xfer->rx_buf) {
957 reinit_completion(&master->xfer_completion);
959 ret = master->transfer_one(master, msg->spi, xfer);
961 SPI_STATISTICS_INCREMENT_FIELD(statm,
963 SPI_STATISTICS_INCREMENT_FIELD(stats,
965 dev_err(&msg->spi->dev,
966 "SPI transfer failed: %d\n", ret);
972 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
973 ms += ms + 100; /* some tolerance */
975 ms = wait_for_completion_timeout(&master->xfer_completion,
976 msecs_to_jiffies(ms));
980 SPI_STATISTICS_INCREMENT_FIELD(statm,
982 SPI_STATISTICS_INCREMENT_FIELD(stats,
984 dev_err(&msg->spi->dev,
985 "SPI transfer timed out\n");
986 msg->status = -ETIMEDOUT;
990 dev_err(&msg->spi->dev,
991 "Bufferless transfer has length %u\n",
995 trace_spi_transfer_stop(msg, xfer);
997 if (msg->status != -EINPROGRESS)
1000 if (xfer->delay_usecs)
1001 udelay(xfer->delay_usecs);
1003 if (xfer->cs_change) {
1004 if (list_is_last(&xfer->transfer_list,
1008 spi_set_cs(msg->spi, false);
1010 spi_set_cs(msg->spi, true);
1014 msg->actual_length += xfer->len;
1018 if (ret != 0 || !keep_cs)
1019 spi_set_cs(msg->spi, false);
1021 if (msg->status == -EINPROGRESS)
1024 if (msg->status && master->handle_err)
1025 master->handle_err(master, msg);
1027 spi_finalize_current_message(master);
1033 * spi_finalize_current_transfer - report completion of a transfer
1034 * @master: the master reporting completion
1036 * Called by SPI drivers using the core transfer_one_message()
1037 * implementation to notify it that the current interrupt driven
1038 * transfer has finished and the next one may be scheduled.
1040 void spi_finalize_current_transfer(struct spi_master *master)
1042 complete(&master->xfer_completion);
1044 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1047 * __spi_pump_messages - function which processes spi message queue
1048 * @master: master to process queue for
1049 * @in_kthread: true if we are in the context of the message pump thread
1051 * This function checks if there is any spi message in the queue that
1052 * needs processing and if so call out to the driver to initialize hardware
1053 * and transfer each message.
1055 * Note that it is called both from the kthread itself and also from
1056 * inside spi_sync(); the queue extraction handling at the top of the
1057 * function should deal with this safely.
1059 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1061 unsigned long flags;
1062 bool was_busy = false;
1066 spin_lock_irqsave(&master->queue_lock, flags);
1068 /* Make sure we are not already running a message */
1069 if (master->cur_msg) {
1070 spin_unlock_irqrestore(&master->queue_lock, flags);
1074 /* If another context is idling the device then defer */
1075 if (master->idling) {
1076 queue_kthread_work(&master->kworker, &master->pump_messages);
1077 spin_unlock_irqrestore(&master->queue_lock, flags);
1081 /* Check if the queue is idle */
1082 if (list_empty(&master->queue) || !master->running) {
1083 if (!master->busy) {
1084 spin_unlock_irqrestore(&master->queue_lock, flags);
1088 /* Only do teardown in the thread */
1090 queue_kthread_work(&master->kworker,
1091 &master->pump_messages);
1092 spin_unlock_irqrestore(&master->queue_lock, flags);
1096 master->busy = false;
1097 master->idling = true;
1098 spin_unlock_irqrestore(&master->queue_lock, flags);
1100 kfree(master->dummy_rx);
1101 master->dummy_rx = NULL;
1102 kfree(master->dummy_tx);
1103 master->dummy_tx = NULL;
1104 if (master->unprepare_transfer_hardware &&
1105 master->unprepare_transfer_hardware(master))
1106 dev_err(&master->dev,
1107 "failed to unprepare transfer hardware\n");
1108 if (master->auto_runtime_pm) {
1109 pm_runtime_mark_last_busy(master->dev.parent);
1110 pm_runtime_put_autosuspend(master->dev.parent);
1112 trace_spi_master_idle(master);
1114 spin_lock_irqsave(&master->queue_lock, flags);
1115 master->idling = false;
1116 spin_unlock_irqrestore(&master->queue_lock, flags);
1120 /* Extract head of queue */
1122 list_first_entry(&master->queue, struct spi_message, queue);
1124 list_del_init(&master->cur_msg->queue);
1128 master->busy = true;
1129 spin_unlock_irqrestore(&master->queue_lock, flags);
1131 if (!was_busy && master->auto_runtime_pm) {
1132 ret = pm_runtime_get_sync(master->dev.parent);
1134 dev_err(&master->dev, "Failed to power device: %d\n",
1141 trace_spi_master_busy(master);
1143 if (!was_busy && master->prepare_transfer_hardware) {
1144 ret = master->prepare_transfer_hardware(master);
1146 dev_err(&master->dev,
1147 "failed to prepare transfer hardware\n");
1149 if (master->auto_runtime_pm)
1150 pm_runtime_put(master->dev.parent);
1155 trace_spi_message_start(master->cur_msg);
1157 if (master->prepare_message) {
1158 ret = master->prepare_message(master, master->cur_msg);
1160 dev_err(&master->dev,
1161 "failed to prepare message: %d\n", ret);
1162 master->cur_msg->status = ret;
1163 spi_finalize_current_message(master);
1166 master->cur_msg_prepared = true;
1169 ret = spi_map_msg(master, master->cur_msg);
1171 master->cur_msg->status = ret;
1172 spi_finalize_current_message(master);
1176 ret = master->transfer_one_message(master, master->cur_msg);
1178 dev_err(&master->dev,
1179 "failed to transfer one message from queue\n");
1185 * spi_pump_messages - kthread work function which processes spi message queue
1186 * @work: pointer to kthread work struct contained in the master struct
1188 static void spi_pump_messages(struct kthread_work *work)
1190 struct spi_master *master =
1191 container_of(work, struct spi_master, pump_messages);
1193 __spi_pump_messages(master, true);
1196 static int spi_init_queue(struct spi_master *master)
1198 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1200 master->running = false;
1201 master->busy = false;
1203 init_kthread_worker(&master->kworker);
1204 master->kworker_task = kthread_run(kthread_worker_fn,
1205 &master->kworker, "%s",
1206 dev_name(&master->dev));
1207 if (IS_ERR(master->kworker_task)) {
1208 dev_err(&master->dev, "failed to create message pump task\n");
1209 return PTR_ERR(master->kworker_task);
1211 init_kthread_work(&master->pump_messages, spi_pump_messages);
1214 * Master config will indicate if this controller should run the
1215 * message pump with high (realtime) priority to reduce the transfer
1216 * latency on the bus by minimising the delay between a transfer
1217 * request and the scheduling of the message pump thread. Without this
1218 * setting the message pump thread will remain at default priority.
1221 dev_info(&master->dev,
1222 "will run message pump with realtime priority\n");
1223 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1230 * spi_get_next_queued_message() - called by driver to check for queued
1232 * @master: the master to check for queued messages
1234 * If there are more messages in the queue, the next message is returned from
1237 * Return: the next message in the queue, else NULL if the queue is empty.
1239 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1241 struct spi_message *next;
1242 unsigned long flags;
1244 /* get a pointer to the next message, if any */
1245 spin_lock_irqsave(&master->queue_lock, flags);
1246 next = list_first_entry_or_null(&master->queue, struct spi_message,
1248 spin_unlock_irqrestore(&master->queue_lock, flags);
1252 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1255 * spi_finalize_current_message() - the current message is complete
1256 * @master: the master to return the message to
1258 * Called by the driver to notify the core that the message in the front of the
1259 * queue is complete and can be removed from the queue.
1261 void spi_finalize_current_message(struct spi_master *master)
1263 struct spi_message *mesg;
1264 unsigned long flags;
1267 spin_lock_irqsave(&master->queue_lock, flags);
1268 mesg = master->cur_msg;
1269 spin_unlock_irqrestore(&master->queue_lock, flags);
1271 spi_unmap_msg(master, mesg);
1273 if (master->cur_msg_prepared && master->unprepare_message) {
1274 ret = master->unprepare_message(master, mesg);
1276 dev_err(&master->dev,
1277 "failed to unprepare message: %d\n", ret);
1281 spin_lock_irqsave(&master->queue_lock, flags);
1282 master->cur_msg = NULL;
1283 master->cur_msg_prepared = false;
1284 queue_kthread_work(&master->kworker, &master->pump_messages);
1285 spin_unlock_irqrestore(&master->queue_lock, flags);
1287 trace_spi_message_done(mesg);
1291 mesg->complete(mesg->context);
1293 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1295 static int spi_start_queue(struct spi_master *master)
1297 unsigned long flags;
1299 spin_lock_irqsave(&master->queue_lock, flags);
1301 if (master->running || master->busy) {
1302 spin_unlock_irqrestore(&master->queue_lock, flags);
1306 master->running = true;
1307 master->cur_msg = NULL;
1308 spin_unlock_irqrestore(&master->queue_lock, flags);
1310 queue_kthread_work(&master->kworker, &master->pump_messages);
1315 static int spi_stop_queue(struct spi_master *master)
1317 unsigned long flags;
1318 unsigned limit = 500;
1321 spin_lock_irqsave(&master->queue_lock, flags);
1324 * This is a bit lame, but is optimized for the common execution path.
1325 * A wait_queue on the master->busy could be used, but then the common
1326 * execution path (pump_messages) would be required to call wake_up or
1327 * friends on every SPI message. Do this instead.
1329 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1330 spin_unlock_irqrestore(&master->queue_lock, flags);
1331 usleep_range(10000, 11000);
1332 spin_lock_irqsave(&master->queue_lock, flags);
1335 if (!list_empty(&master->queue) || master->busy)
1338 master->running = false;
1340 spin_unlock_irqrestore(&master->queue_lock, flags);
1343 dev_warn(&master->dev,
1344 "could not stop message queue\n");
1350 static int spi_destroy_queue(struct spi_master *master)
1354 ret = spi_stop_queue(master);
1357 * flush_kthread_worker will block until all work is done.
1358 * If the reason that stop_queue timed out is that the work will never
1359 * finish, then it does no good to call flush/stop thread, so
1363 dev_err(&master->dev, "problem destroying queue\n");
1367 flush_kthread_worker(&master->kworker);
1368 kthread_stop(master->kworker_task);
1373 static int __spi_queued_transfer(struct spi_device *spi,
1374 struct spi_message *msg,
1377 struct spi_master *master = spi->master;
1378 unsigned long flags;
1380 spin_lock_irqsave(&master->queue_lock, flags);
1382 if (!master->running) {
1383 spin_unlock_irqrestore(&master->queue_lock, flags);
1386 msg->actual_length = 0;
1387 msg->status = -EINPROGRESS;
1389 list_add_tail(&msg->queue, &master->queue);
1390 if (!master->busy && need_pump)
1391 queue_kthread_work(&master->kworker, &master->pump_messages);
1393 spin_unlock_irqrestore(&master->queue_lock, flags);
1398 * spi_queued_transfer - transfer function for queued transfers
1399 * @spi: spi device which is requesting transfer
1400 * @msg: spi message which is to handled is queued to driver queue
1402 * Return: zero on success, else a negative error code.
1404 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1406 return __spi_queued_transfer(spi, msg, true);
1409 static int spi_master_initialize_queue(struct spi_master *master)
1413 master->transfer = spi_queued_transfer;
1414 if (!master->transfer_one_message)
1415 master->transfer_one_message = spi_transfer_one_message;
1417 /* Initialize and start queue */
1418 ret = spi_init_queue(master);
1420 dev_err(&master->dev, "problem initializing queue\n");
1421 goto err_init_queue;
1423 master->queued = true;
1424 ret = spi_start_queue(master);
1426 dev_err(&master->dev, "problem starting queue\n");
1427 goto err_start_queue;
1433 spi_destroy_queue(master);
1438 /*-------------------------------------------------------------------------*/
1440 #if defined(CONFIG_OF)
1441 static struct spi_device *
1442 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1444 struct spi_device *spi;
1448 /* Alloc an spi_device */
1449 spi = spi_alloc_device(master);
1451 dev_err(&master->dev, "spi_device alloc error for %s\n",
1457 /* Select device driver */
1458 rc = of_modalias_node(nc, spi->modalias,
1459 sizeof(spi->modalias));
1461 dev_err(&master->dev, "cannot find modalias for %s\n",
1466 /* Device address */
1467 rc = of_property_read_u32(nc, "reg", &value);
1469 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1473 spi->chip_select = value;
1475 /* Mode (clock phase/polarity/etc.) */
1476 if (of_find_property(nc, "spi-cpha", NULL))
1477 spi->mode |= SPI_CPHA;
1478 if (of_find_property(nc, "spi-cpol", NULL))
1479 spi->mode |= SPI_CPOL;
1480 if (of_find_property(nc, "spi-cs-high", NULL))
1481 spi->mode |= SPI_CS_HIGH;
1482 if (of_find_property(nc, "spi-3wire", NULL))
1483 spi->mode |= SPI_3WIRE;
1484 if (of_find_property(nc, "spi-lsb-first", NULL))
1485 spi->mode |= SPI_LSB_FIRST;
1487 /* Device DUAL/QUAD mode */
1488 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1493 spi->mode |= SPI_TX_DUAL;
1496 spi->mode |= SPI_TX_QUAD;
1499 dev_warn(&master->dev,
1500 "spi-tx-bus-width %d not supported\n",
1506 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1511 spi->mode |= SPI_RX_DUAL;
1514 spi->mode |= SPI_RX_QUAD;
1517 dev_warn(&master->dev,
1518 "spi-rx-bus-width %d not supported\n",
1525 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1527 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1531 spi->max_speed_hz = value;
1533 /* Store a pointer to the node in the device structure */
1535 spi->dev.of_node = nc;
1537 /* Register the new device */
1538 rc = spi_add_device(spi);
1540 dev_err(&master->dev, "spi_device register error %s\n",
1553 * of_register_spi_devices() - Register child devices onto the SPI bus
1554 * @master: Pointer to spi_master device
1556 * Registers an spi_device for each child node of master node which has a 'reg'
1559 static void of_register_spi_devices(struct spi_master *master)
1561 struct spi_device *spi;
1562 struct device_node *nc;
1564 if (!master->dev.of_node)
1567 for_each_available_child_of_node(master->dev.of_node, nc) {
1568 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1570 spi = of_register_spi_device(master, nc);
1572 dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1577 static void of_register_spi_devices(struct spi_master *master) { }
1581 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1583 struct spi_device *spi = data;
1584 struct spi_master *master = spi->master;
1586 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1587 struct acpi_resource_spi_serialbus *sb;
1589 sb = &ares->data.spi_serial_bus;
1590 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1592 * ACPI DeviceSelection numbering is handled by the
1593 * host controller driver in Windows and can vary
1594 * from driver to driver. In Linux we always expect
1595 * 0 .. max - 1 so we need to ask the driver to
1596 * translate between the two schemes.
1598 if (master->fw_translate_cs) {
1599 int cs = master->fw_translate_cs(master,
1600 sb->device_selection);
1603 spi->chip_select = cs;
1605 spi->chip_select = sb->device_selection;
1608 spi->max_speed_hz = sb->connection_speed;
1610 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1611 spi->mode |= SPI_CPHA;
1612 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1613 spi->mode |= SPI_CPOL;
1614 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1615 spi->mode |= SPI_CS_HIGH;
1617 } else if (spi->irq < 0) {
1620 if (acpi_dev_resource_interrupt(ares, 0, &r))
1624 /* Always tell the ACPI core to skip this resource */
1628 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1629 void *data, void **return_value)
1631 struct spi_master *master = data;
1632 struct list_head resource_list;
1633 struct acpi_device *adev;
1634 struct spi_device *spi;
1637 if (acpi_bus_get_device(handle, &adev))
1639 if (acpi_bus_get_status(adev) || !adev->status.present)
1642 spi = spi_alloc_device(master);
1644 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1645 dev_name(&adev->dev));
1646 return AE_NO_MEMORY;
1649 ACPI_COMPANION_SET(&spi->dev, adev);
1652 INIT_LIST_HEAD(&resource_list);
1653 ret = acpi_dev_get_resources(adev, &resource_list,
1654 acpi_spi_add_resource, spi);
1655 acpi_dev_free_resource_list(&resource_list);
1657 if (ret < 0 || !spi->max_speed_hz) {
1663 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1665 adev->power.flags.ignore_parent = true;
1666 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1667 if (spi_add_device(spi)) {
1668 adev->power.flags.ignore_parent = false;
1669 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1670 dev_name(&adev->dev));
1677 static void acpi_register_spi_devices(struct spi_master *master)
1682 handle = ACPI_HANDLE(master->dev.parent);
1686 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1687 acpi_spi_add_device, NULL,
1689 if (ACPI_FAILURE(status))
1690 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1693 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1694 #endif /* CONFIG_ACPI */
1696 static void spi_master_release(struct device *dev)
1698 struct spi_master *master;
1700 master = container_of(dev, struct spi_master, dev);
1704 static struct class spi_master_class = {
1705 .name = "spi_master",
1706 .owner = THIS_MODULE,
1707 .dev_release = spi_master_release,
1708 .dev_groups = spi_master_groups,
1713 * spi_alloc_master - allocate SPI master controller
1714 * @dev: the controller, possibly using the platform_bus
1715 * @size: how much zeroed driver-private data to allocate; the pointer to this
1716 * memory is in the driver_data field of the returned device,
1717 * accessible with spi_master_get_devdata().
1718 * Context: can sleep
1720 * This call is used only by SPI master controller drivers, which are the
1721 * only ones directly touching chip registers. It's how they allocate
1722 * an spi_master structure, prior to calling spi_register_master().
1724 * This must be called from context that can sleep.
1726 * The caller is responsible for assigning the bus number and initializing
1727 * the master's methods before calling spi_register_master(); and (after errors
1728 * adding the device) calling spi_master_put() to prevent a memory leak.
1730 * Return: the SPI master structure on success, else NULL.
1732 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1734 struct spi_master *master;
1739 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1743 device_initialize(&master->dev);
1744 master->bus_num = -1;
1745 master->num_chipselect = 1;
1746 master->dev.class = &spi_master_class;
1747 master->dev.parent = dev;
1748 spi_master_set_devdata(master, &master[1]);
1752 EXPORT_SYMBOL_GPL(spi_alloc_master);
1755 static int of_spi_register_master(struct spi_master *master)
1758 struct device_node *np = master->dev.of_node;
1763 nb = of_gpio_named_count(np, "cs-gpios");
1764 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1766 /* Return error only for an incorrectly formed cs-gpios property */
1767 if (nb == 0 || nb == -ENOENT)
1772 cs = devm_kzalloc(&master->dev,
1773 sizeof(int) * master->num_chipselect,
1775 master->cs_gpios = cs;
1777 if (!master->cs_gpios)
1780 for (i = 0; i < master->num_chipselect; i++)
1783 for (i = 0; i < nb; i++)
1784 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1789 static int of_spi_register_master(struct spi_master *master)
1796 * spi_register_master - register SPI master controller
1797 * @master: initialized master, originally from spi_alloc_master()
1798 * Context: can sleep
1800 * SPI master controllers connect to their drivers using some non-SPI bus,
1801 * such as the platform bus. The final stage of probe() in that code
1802 * includes calling spi_register_master() to hook up to this SPI bus glue.
1804 * SPI controllers use board specific (often SOC specific) bus numbers,
1805 * and board-specific addressing for SPI devices combines those numbers
1806 * with chip select numbers. Since SPI does not directly support dynamic
1807 * device identification, boards need configuration tables telling which
1808 * chip is at which address.
1810 * This must be called from context that can sleep. It returns zero on
1811 * success, else a negative error code (dropping the master's refcount).
1812 * After a successful return, the caller is responsible for calling
1813 * spi_unregister_master().
1815 * Return: zero on success, else a negative error code.
1817 int spi_register_master(struct spi_master *master)
1819 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1820 struct device *dev = master->dev.parent;
1821 struct boardinfo *bi;
1822 int status = -ENODEV;
1828 status = of_spi_register_master(master);
1832 /* even if it's just one always-selected device, there must
1833 * be at least one chipselect
1835 if (master->num_chipselect == 0)
1838 if ((master->bus_num < 0) && master->dev.of_node)
1839 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1841 /* convention: dynamically assigned bus IDs count down from the max */
1842 if (master->bus_num < 0) {
1843 /* FIXME switch to an IDR based scheme, something like
1844 * I2C now uses, so we can't run out of "dynamic" IDs
1846 master->bus_num = atomic_dec_return(&dyn_bus_id);
1850 INIT_LIST_HEAD(&master->queue);
1851 spin_lock_init(&master->queue_lock);
1852 spin_lock_init(&master->bus_lock_spinlock);
1853 mutex_init(&master->bus_lock_mutex);
1854 master->bus_lock_flag = 0;
1855 init_completion(&master->xfer_completion);
1856 if (!master->max_dma_len)
1857 master->max_dma_len = INT_MAX;
1859 /* register the device, then userspace will see it.
1860 * registration fails if the bus ID is in use.
1862 dev_set_name(&master->dev, "spi%u", master->bus_num);
1863 status = device_add(&master->dev);
1866 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1867 dynamic ? " (dynamic)" : "");
1869 /* If we're using a queued driver, start the queue */
1870 if (master->transfer)
1871 dev_info(dev, "master is unqueued, this is deprecated\n");
1873 status = spi_master_initialize_queue(master);
1875 device_del(&master->dev);
1879 /* add statistics */
1880 spin_lock_init(&master->statistics.lock);
1882 mutex_lock(&board_lock);
1883 list_add_tail(&master->list, &spi_master_list);
1884 list_for_each_entry(bi, &board_list, list)
1885 spi_match_master_to_boardinfo(master, &bi->board_info);
1886 mutex_unlock(&board_lock);
1888 /* Register devices from the device tree and ACPI */
1889 of_register_spi_devices(master);
1890 acpi_register_spi_devices(master);
1894 EXPORT_SYMBOL_GPL(spi_register_master);
1896 static void devm_spi_unregister(struct device *dev, void *res)
1898 spi_unregister_master(*(struct spi_master **)res);
1902 * dev_spi_register_master - register managed SPI master controller
1903 * @dev: device managing SPI master
1904 * @master: initialized master, originally from spi_alloc_master()
1905 * Context: can sleep
1907 * Register a SPI device as with spi_register_master() which will
1908 * automatically be unregister
1910 * Return: zero on success, else a negative error code.
1912 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1914 struct spi_master **ptr;
1917 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1921 ret = spi_register_master(master);
1924 devres_add(dev, ptr);
1931 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1933 static int __unregister(struct device *dev, void *null)
1935 spi_unregister_device(to_spi_device(dev));
1940 * spi_unregister_master - unregister SPI master controller
1941 * @master: the master being unregistered
1942 * Context: can sleep
1944 * This call is used only by SPI master controller drivers, which are the
1945 * only ones directly touching chip registers.
1947 * This must be called from context that can sleep.
1949 void spi_unregister_master(struct spi_master *master)
1953 if (master->queued) {
1954 if (spi_destroy_queue(master))
1955 dev_err(&master->dev, "queue remove failed\n");
1958 mutex_lock(&board_lock);
1959 list_del(&master->list);
1960 mutex_unlock(&board_lock);
1962 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1963 device_unregister(&master->dev);
1965 EXPORT_SYMBOL_GPL(spi_unregister_master);
1967 int spi_master_suspend(struct spi_master *master)
1971 /* Basically no-ops for non-queued masters */
1972 if (!master->queued)
1975 ret = spi_stop_queue(master);
1977 dev_err(&master->dev, "queue stop failed\n");
1981 EXPORT_SYMBOL_GPL(spi_master_suspend);
1983 int spi_master_resume(struct spi_master *master)
1987 if (!master->queued)
1990 ret = spi_start_queue(master);
1992 dev_err(&master->dev, "queue restart failed\n");
1996 EXPORT_SYMBOL_GPL(spi_master_resume);
1998 static int __spi_master_match(struct device *dev, const void *data)
2000 struct spi_master *m;
2001 const u16 *bus_num = data;
2003 m = container_of(dev, struct spi_master, dev);
2004 return m->bus_num == *bus_num;
2008 * spi_busnum_to_master - look up master associated with bus_num
2009 * @bus_num: the master's bus number
2010 * Context: can sleep
2012 * This call may be used with devices that are registered after
2013 * arch init time. It returns a refcounted pointer to the relevant
2014 * spi_master (which the caller must release), or NULL if there is
2015 * no such master registered.
2017 * Return: the SPI master structure on success, else NULL.
2019 struct spi_master *spi_busnum_to_master(u16 bus_num)
2022 struct spi_master *master = NULL;
2024 dev = class_find_device(&spi_master_class, NULL, &bus_num,
2025 __spi_master_match);
2027 master = container_of(dev, struct spi_master, dev);
2028 /* reference got in class_find_device */
2031 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2034 /*-------------------------------------------------------------------------*/
2036 /* Core methods for SPI master protocol drivers. Some of the
2037 * other core methods are currently defined as inline functions.
2040 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2042 if (master->bits_per_word_mask) {
2043 /* Only 32 bits fit in the mask */
2044 if (bits_per_word > 32)
2046 if (!(master->bits_per_word_mask &
2047 SPI_BPW_MASK(bits_per_word)))
2055 * spi_setup - setup SPI mode and clock rate
2056 * @spi: the device whose settings are being modified
2057 * Context: can sleep, and no requests are queued to the device
2059 * SPI protocol drivers may need to update the transfer mode if the
2060 * device doesn't work with its default. They may likewise need
2061 * to update clock rates or word sizes from initial values. This function
2062 * changes those settings, and must be called from a context that can sleep.
2063 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2064 * effect the next time the device is selected and data is transferred to
2065 * or from it. When this function returns, the spi device is deselected.
2067 * Note that this call will fail if the protocol driver specifies an option
2068 * that the underlying controller or its driver does not support. For
2069 * example, not all hardware supports wire transfers using nine bit words,
2070 * LSB-first wire encoding, or active-high chipselects.
2072 * Return: zero on success, else a negative error code.
2074 int spi_setup(struct spi_device *spi)
2076 unsigned bad_bits, ugly_bits;
2079 /* check mode to prevent that DUAL and QUAD set at the same time
2081 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2082 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2084 "setup: can not select dual and quad at the same time\n");
2087 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2089 if ((spi->mode & SPI_3WIRE) && (spi->mode &
2090 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2092 /* help drivers fail *cleanly* when they need options
2093 * that aren't supported with their current master
2095 bad_bits = spi->mode & ~spi->master->mode_bits;
2096 ugly_bits = bad_bits &
2097 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2100 "setup: ignoring unsupported mode bits %x\n",
2102 spi->mode &= ~ugly_bits;
2103 bad_bits &= ~ugly_bits;
2106 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2111 if (!spi->bits_per_word)
2112 spi->bits_per_word = 8;
2114 status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2118 if (!spi->max_speed_hz)
2119 spi->max_speed_hz = spi->master->max_speed_hz;
2121 if (spi->master->setup)
2122 status = spi->master->setup(spi);
2124 spi_set_cs(spi, false);
2126 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2127 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2128 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2129 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2130 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2131 (spi->mode & SPI_LOOP) ? "loopback, " : "",
2132 spi->bits_per_word, spi->max_speed_hz,
2137 EXPORT_SYMBOL_GPL(spi_setup);
2139 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2141 struct spi_master *master = spi->master;
2142 struct spi_transfer *xfer;
2145 if (list_empty(&message->transfers))
2148 /* Half-duplex links include original MicroWire, and ones with
2149 * only one data pin like SPI_3WIRE (switches direction) or where
2150 * either MOSI or MISO is missing. They can also be caused by
2151 * software limitations.
2153 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2154 || (spi->mode & SPI_3WIRE)) {
2155 unsigned flags = master->flags;
2157 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2158 if (xfer->rx_buf && xfer->tx_buf)
2160 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2162 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2168 * Set transfer bits_per_word and max speed as spi device default if
2169 * it is not set for this transfer.
2170 * Set transfer tx_nbits and rx_nbits as single transfer default
2171 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2173 message->frame_length = 0;
2174 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2175 message->frame_length += xfer->len;
2176 if (!xfer->bits_per_word)
2177 xfer->bits_per_word = spi->bits_per_word;
2179 if (!xfer->speed_hz)
2180 xfer->speed_hz = spi->max_speed_hz;
2181 if (!xfer->speed_hz)
2182 xfer->speed_hz = master->max_speed_hz;
2184 if (master->max_speed_hz &&
2185 xfer->speed_hz > master->max_speed_hz)
2186 xfer->speed_hz = master->max_speed_hz;
2188 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2192 * SPI transfer length should be multiple of SPI word size
2193 * where SPI word size should be power-of-two multiple
2195 if (xfer->bits_per_word <= 8)
2197 else if (xfer->bits_per_word <= 16)
2202 /* No partial transfers accepted */
2203 if (xfer->len % w_size)
2206 if (xfer->speed_hz && master->min_speed_hz &&
2207 xfer->speed_hz < master->min_speed_hz)
2210 if (xfer->tx_buf && !xfer->tx_nbits)
2211 xfer->tx_nbits = SPI_NBITS_SINGLE;
2212 if (xfer->rx_buf && !xfer->rx_nbits)
2213 xfer->rx_nbits = SPI_NBITS_SINGLE;
2214 /* check transfer tx/rx_nbits:
2215 * 1. check the value matches one of single, dual and quad
2216 * 2. check tx/rx_nbits match the mode in spi_device
2219 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2220 xfer->tx_nbits != SPI_NBITS_DUAL &&
2221 xfer->tx_nbits != SPI_NBITS_QUAD)
2223 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2224 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2226 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2227 !(spi->mode & SPI_TX_QUAD))
2230 /* check transfer rx_nbits */
2232 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2233 xfer->rx_nbits != SPI_NBITS_DUAL &&
2234 xfer->rx_nbits != SPI_NBITS_QUAD)
2236 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2237 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2239 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2240 !(spi->mode & SPI_RX_QUAD))
2245 message->status = -EINPROGRESS;
2250 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2252 struct spi_master *master = spi->master;
2256 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2257 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2259 trace_spi_message_submit(message);
2261 return master->transfer(spi, message);
2265 * spi_async - asynchronous SPI transfer
2266 * @spi: device with which data will be exchanged
2267 * @message: describes the data transfers, including completion callback
2268 * Context: any (irqs may be blocked, etc)
2270 * This call may be used in_irq and other contexts which can't sleep,
2271 * as well as from task contexts which can sleep.
2273 * The completion callback is invoked in a context which can't sleep.
2274 * Before that invocation, the value of message->status is undefined.
2275 * When the callback is issued, message->status holds either zero (to
2276 * indicate complete success) or a negative error code. After that
2277 * callback returns, the driver which issued the transfer request may
2278 * deallocate the associated memory; it's no longer in use by any SPI
2279 * core or controller driver code.
2281 * Note that although all messages to a spi_device are handled in
2282 * FIFO order, messages may go to different devices in other orders.
2283 * Some device might be higher priority, or have various "hard" access
2284 * time requirements, for example.
2286 * On detection of any fault during the transfer, processing of
2287 * the entire message is aborted, and the device is deselected.
2288 * Until returning from the associated message completion callback,
2289 * no other spi_message queued to that device will be processed.
2290 * (This rule applies equally to all the synchronous transfer calls,
2291 * which are wrappers around this core asynchronous primitive.)
2293 * Return: zero on success, else a negative error code.
2295 int spi_async(struct spi_device *spi, struct spi_message *message)
2297 struct spi_master *master = spi->master;
2299 unsigned long flags;
2301 ret = __spi_validate(spi, message);
2305 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2307 if (master->bus_lock_flag)
2310 ret = __spi_async(spi, message);
2312 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2316 EXPORT_SYMBOL_GPL(spi_async);
2319 * spi_async_locked - version of spi_async with exclusive bus usage
2320 * @spi: device with which data will be exchanged
2321 * @message: describes the data transfers, including completion callback
2322 * Context: any (irqs may be blocked, etc)
2324 * This call may be used in_irq and other contexts which can't sleep,
2325 * as well as from task contexts which can sleep.
2327 * The completion callback is invoked in a context which can't sleep.
2328 * Before that invocation, the value of message->status is undefined.
2329 * When the callback is issued, message->status holds either zero (to
2330 * indicate complete success) or a negative error code. After that
2331 * callback returns, the driver which issued the transfer request may
2332 * deallocate the associated memory; it's no longer in use by any SPI
2333 * core or controller driver code.
2335 * Note that although all messages to a spi_device are handled in
2336 * FIFO order, messages may go to different devices in other orders.
2337 * Some device might be higher priority, or have various "hard" access
2338 * time requirements, for example.
2340 * On detection of any fault during the transfer, processing of
2341 * the entire message is aborted, and the device is deselected.
2342 * Until returning from the associated message completion callback,
2343 * no other spi_message queued to that device will be processed.
2344 * (This rule applies equally to all the synchronous transfer calls,
2345 * which are wrappers around this core asynchronous primitive.)
2347 * Return: zero on success, else a negative error code.
2349 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2351 struct spi_master *master = spi->master;
2353 unsigned long flags;
2355 ret = __spi_validate(spi, message);
2359 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2361 ret = __spi_async(spi, message);
2363 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2368 EXPORT_SYMBOL_GPL(spi_async_locked);
2371 /*-------------------------------------------------------------------------*/
2373 /* Utility methods for SPI master protocol drivers, layered on
2374 * top of the core. Some other utility methods are defined as
2378 static void spi_complete(void *arg)
2383 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2386 DECLARE_COMPLETION_ONSTACK(done);
2388 struct spi_master *master = spi->master;
2389 unsigned long flags;
2391 status = __spi_validate(spi, message);
2395 message->complete = spi_complete;
2396 message->context = &done;
2399 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2400 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2403 mutex_lock(&master->bus_lock_mutex);
2405 /* If we're not using the legacy transfer method then we will
2406 * try to transfer in the calling context so special case.
2407 * This code would be less tricky if we could remove the
2408 * support for driver implemented message queues.
2410 if (master->transfer == spi_queued_transfer) {
2411 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2413 trace_spi_message_submit(message);
2415 status = __spi_queued_transfer(spi, message, false);
2417 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2419 status = spi_async_locked(spi, message);
2423 mutex_unlock(&master->bus_lock_mutex);
2426 /* Push out the messages in the calling context if we
2429 if (master->transfer == spi_queued_transfer) {
2430 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2431 spi_sync_immediate);
2432 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2433 spi_sync_immediate);
2434 __spi_pump_messages(master, false);
2437 wait_for_completion(&done);
2438 status = message->status;
2440 message->context = NULL;
2445 * spi_sync - blocking/synchronous SPI data transfers
2446 * @spi: device with which data will be exchanged
2447 * @message: describes the data transfers
2448 * Context: can sleep
2450 * This call may only be used from a context that may sleep. The sleep
2451 * is non-interruptible, and has no timeout. Low-overhead controller
2452 * drivers may DMA directly into and out of the message buffers.
2454 * Note that the SPI device's chip select is active during the message,
2455 * and then is normally disabled between messages. Drivers for some
2456 * frequently-used devices may want to minimize costs of selecting a chip,
2457 * by leaving it selected in anticipation that the next message will go
2458 * to the same chip. (That may increase power usage.)
2460 * Also, the caller is guaranteeing that the memory associated with the
2461 * message will not be freed before this call returns.
2463 * Return: zero on success, else a negative error code.
2465 int spi_sync(struct spi_device *spi, struct spi_message *message)
2467 return __spi_sync(spi, message, 0);
2469 EXPORT_SYMBOL_GPL(spi_sync);
2472 * spi_sync_locked - version of spi_sync with exclusive bus usage
2473 * @spi: device with which data will be exchanged
2474 * @message: describes the data transfers
2475 * Context: can sleep
2477 * This call may only be used from a context that may sleep. The sleep
2478 * is non-interruptible, and has no timeout. Low-overhead controller
2479 * drivers may DMA directly into and out of the message buffers.
2481 * This call should be used by drivers that require exclusive access to the
2482 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2483 * be released by a spi_bus_unlock call when the exclusive access is over.
2485 * Return: zero on success, else a negative error code.
2487 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2489 return __spi_sync(spi, message, 1);
2491 EXPORT_SYMBOL_GPL(spi_sync_locked);
2494 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2495 * @master: SPI bus master that should be locked for exclusive bus access
2496 * Context: can sleep
2498 * This call may only be used from a context that may sleep. The sleep
2499 * is non-interruptible, and has no timeout.
2501 * This call should be used by drivers that require exclusive access to the
2502 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2503 * exclusive access is over. Data transfer must be done by spi_sync_locked
2504 * and spi_async_locked calls when the SPI bus lock is held.
2506 * Return: always zero.
2508 int spi_bus_lock(struct spi_master *master)
2510 unsigned long flags;
2512 mutex_lock(&master->bus_lock_mutex);
2514 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2515 master->bus_lock_flag = 1;
2516 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2518 /* mutex remains locked until spi_bus_unlock is called */
2522 EXPORT_SYMBOL_GPL(spi_bus_lock);
2525 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2526 * @master: SPI bus master that was locked for exclusive bus access
2527 * Context: can sleep
2529 * This call may only be used from a context that may sleep. The sleep
2530 * is non-interruptible, and has no timeout.
2532 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2535 * Return: always zero.
2537 int spi_bus_unlock(struct spi_master *master)
2539 master->bus_lock_flag = 0;
2541 mutex_unlock(&master->bus_lock_mutex);
2545 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2547 /* portable code must never pass more than 32 bytes */
2548 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2553 * spi_write_then_read - SPI synchronous write followed by read
2554 * @spi: device with which data will be exchanged
2555 * @txbuf: data to be written (need not be dma-safe)
2556 * @n_tx: size of txbuf, in bytes
2557 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2558 * @n_rx: size of rxbuf, in bytes
2559 * Context: can sleep
2561 * This performs a half duplex MicroWire style transaction with the
2562 * device, sending txbuf and then reading rxbuf. The return value
2563 * is zero for success, else a negative errno status code.
2564 * This call may only be used from a context that may sleep.
2566 * Parameters to this routine are always copied using a small buffer;
2567 * portable code should never use this for more than 32 bytes.
2568 * Performance-sensitive or bulk transfer code should instead use
2569 * spi_{async,sync}() calls with dma-safe buffers.
2571 * Return: zero on success, else a negative error code.
2573 int spi_write_then_read(struct spi_device *spi,
2574 const void *txbuf, unsigned n_tx,
2575 void *rxbuf, unsigned n_rx)
2577 static DEFINE_MUTEX(lock);
2580 struct spi_message message;
2581 struct spi_transfer x[2];
2584 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2585 * copying here, (as a pure convenience thing), but we can
2586 * keep heap costs out of the hot path unless someone else is
2587 * using the pre-allocated buffer or the transfer is too large.
2589 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2590 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2591 GFP_KERNEL | GFP_DMA);
2598 spi_message_init(&message);
2599 memset(x, 0, sizeof(x));
2602 spi_message_add_tail(&x[0], &message);
2606 spi_message_add_tail(&x[1], &message);
2609 memcpy(local_buf, txbuf, n_tx);
2610 x[0].tx_buf = local_buf;
2611 x[1].rx_buf = local_buf + n_tx;
2614 status = spi_sync(spi, &message);
2616 memcpy(rxbuf, x[1].rx_buf, n_rx);
2618 if (x[0].tx_buf == buf)
2619 mutex_unlock(&lock);
2625 EXPORT_SYMBOL_GPL(spi_write_then_read);
2627 /*-------------------------------------------------------------------------*/
2629 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2630 static int __spi_of_device_match(struct device *dev, void *data)
2632 return dev->of_node == data;
2635 /* must call put_device() when done with returned spi_device device */
2636 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2638 struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2639 __spi_of_device_match);
2640 return dev ? to_spi_device(dev) : NULL;
2643 static int __spi_of_master_match(struct device *dev, const void *data)
2645 return dev->of_node == data;
2648 /* the spi masters are not using spi_bus, so we find it with another way */
2649 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2653 dev = class_find_device(&spi_master_class, NULL, node,
2654 __spi_of_master_match);
2658 /* reference got in class_find_device */
2659 return container_of(dev, struct spi_master, dev);
2662 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2665 struct of_reconfig_data *rd = arg;
2666 struct spi_master *master;
2667 struct spi_device *spi;
2669 switch (of_reconfig_get_state_change(action, arg)) {
2670 case OF_RECONFIG_CHANGE_ADD:
2671 master = of_find_spi_master_by_node(rd->dn->parent);
2673 return NOTIFY_OK; /* not for us */
2675 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
2676 put_device(&master->dev);
2680 spi = of_register_spi_device(master, rd->dn);
2681 put_device(&master->dev);
2684 pr_err("%s: failed to create for '%s'\n",
2685 __func__, rd->dn->full_name);
2686 return notifier_from_errno(PTR_ERR(spi));
2690 case OF_RECONFIG_CHANGE_REMOVE:
2691 /* already depopulated? */
2692 if (!of_node_check_flag(rd->dn, OF_POPULATED))
2695 /* find our device by node */
2696 spi = of_find_spi_device_by_node(rd->dn);
2698 return NOTIFY_OK; /* no? not meant for us */
2700 /* unregister takes one ref away */
2701 spi_unregister_device(spi);
2703 /* and put the reference of the find */
2704 put_device(&spi->dev);
2711 static struct notifier_block spi_of_notifier = {
2712 .notifier_call = of_spi_notify,
2714 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2715 extern struct notifier_block spi_of_notifier;
2716 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2718 static int __init spi_init(void)
2722 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2728 status = bus_register(&spi_bus_type);
2732 status = class_register(&spi_master_class);
2736 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2737 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
2742 bus_unregister(&spi_bus_type);
2750 /* board_info is normally registered in arch_initcall(),
2751 * but even essential drivers wait till later
2753 * REVISIT only boardinfo really needs static linking. the rest (device and
2754 * driver registration) _could_ be dynamically linked (modular) ... costs
2755 * include needing to have boardinfo data structures be much more public.
2757 postcore_initcall(spi_init);