2 * Murata ZPA2326 pressure and temperature sensor IIO driver
4 * Copyright (c) 2016 Parrot S.A.
6 * Author: Gregor Boirie <gregor.boirie@parrot.com>
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published by
10 * the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
19 * DOC: ZPA2326 theory of operations
21 * This driver supports %INDIO_DIRECT_MODE and %INDIO_BUFFER_TRIGGERED IIO
23 * A internal hardware trigger is also implemented to dispatch registered IIO
24 * trigger consumers upon "sample ready" interrupts.
26 * ZPA2326 hardware supports 2 sampling mode: one shot and continuous.
28 * A complete one shot sampling cycle gets device out of low power mode,
29 * performs pressure and temperature measurements, then automatically switches
30 * back to low power mode. It is meant for on demand sampling with optimal power
31 * saving at the cost of lower sampling rate and higher software overhead.
32 * This is a natural candidate for IIO read_raw hook implementation
33 * (%INDIO_DIRECT_MODE). It is also used for triggered buffering support to
34 * ensure explicit synchronization with external trigger events
35 * (%INDIO_BUFFER_TRIGGERED).
37 * The continuous mode works according to a periodic hardware measurement
38 * process continuously pushing samples into an internal hardware FIFO (for
39 * pressure samples only). Measurement cycle completion may be signaled by a
40 * "sample ready" interrupt.
41 * Typical software sequence of operations :
42 * - get device out of low power mode,
43 * - setup hardware sampling period,
44 * - at end of period, upon data ready interrupt: pop pressure samples out of
45 * hardware FIFO and fetch temperature sample
46 * - when no longer needed, stop sampling process by putting device into
48 * This mode is used to implement %INDIO_BUFFER_TRIGGERED mode if device tree
49 * declares a valid interrupt line. In this case, the internal hardware trigger
52 * Note that hardware sampling frequency is taken into account only when
53 * internal hardware trigger is attached as the highest sampling rate seems to
54 * be the most energy efficient.
57 * preset pressure threshold crossing / IIO events ;
58 * differential pressure sampling ;
59 * hardware samples averaging.
62 #include <linux/module.h>
63 #include <linux/kernel.h>
64 #include <linux/delay.h>
65 #include <linux/interrupt.h>
66 #include <linux/regulator/consumer.h>
67 #include <linux/pm_runtime.h>
68 #include <linux/regmap.h>
69 #include <linux/iio/iio.h>
70 #include <linux/iio/sysfs.h>
71 #include <linux/iio/buffer.h>
72 #include <linux/iio/trigger.h>
73 #include <linux/iio/trigger_consumer.h>
74 #include <linux/iio/triggered_buffer.h>
77 /* 200 ms should be enough for the longest conversion time in one-shot mode. */
78 #define ZPA2326_CONVERSION_JIFFIES (HZ / 5)
80 /* There should be a 1 ms delay (Tpup) after getting out of reset. */
81 #define ZPA2326_TPUP_USEC_MIN (1000)
82 #define ZPA2326_TPUP_USEC_MAX (2000)
85 * struct zpa2326_frequency - Hardware sampling frequency descriptor
86 * @hz : Frequency in Hertz.
87 * @odr: Output Data Rate word as expected by %ZPA2326_CTRL_REG3_REG.
89 struct zpa2326_frequency {
95 * Keep these in strict ascending order: last array entry is expected to
96 * correspond to the highest sampling frequency.
98 static const struct zpa2326_frequency zpa2326_sampling_frequencies[] = {
99 { .hz = 1, .odr = 1 << ZPA2326_CTRL_REG3_ODR_SHIFT },
100 { .hz = 5, .odr = 5 << ZPA2326_CTRL_REG3_ODR_SHIFT },
101 { .hz = 11, .odr = 6 << ZPA2326_CTRL_REG3_ODR_SHIFT },
102 { .hz = 23, .odr = 7 << ZPA2326_CTRL_REG3_ODR_SHIFT },
105 /* Return the highest hardware sampling frequency available. */
106 static const struct zpa2326_frequency *zpa2326_highest_frequency(void)
108 return &zpa2326_sampling_frequencies[
109 ARRAY_SIZE(zpa2326_sampling_frequencies) - 1];
113 * struct zpa_private - Per-device internal private state
114 * @timestamp: Buffered samples ready datum.
115 * @regmap: Underlying I2C / SPI bus adapter used to abstract slave register
117 * @result: Allows sampling logic to get completion status of operations
118 * that interrupt handlers perform asynchronously.
119 * @data_ready: Interrupt handler uses this to wake user context up at sampling
120 * operation completion.
121 * @trigger: Optional hardware / interrupt driven trigger used to notify
122 * external devices a new sample is ready.
123 * @waken: Flag indicating whether or not device has just been powered on.
124 * @irq: Optional interrupt line: negative or zero if not declared into
125 * DT, in which case sampling logic keeps polling status register
126 * to detect completion.
127 * @frequency: Current hardware sampling frequency.
128 * @vref: Power / voltage reference.
129 * @vdd: Power supply.
131 struct zpa2326_private {
133 struct regmap *regmap;
135 struct completion data_ready;
136 struct iio_trigger *trigger;
139 const struct zpa2326_frequency *frequency;
140 struct regulator *vref;
141 struct regulator *vdd;
144 #define zpa2326_err(_idev, _format, _arg...) \
145 dev_err(_idev->dev.parent, _format, ##_arg)
147 #define zpa2326_warn(_idev, _format, _arg...) \
148 dev_warn(_idev->dev.parent, _format, ##_arg)
151 #define zpa2326_dbg(_idev, _format, _arg...) \
152 dev_dbg(_idev->dev.parent, _format, ##_arg)
154 #define zpa2326_dbg(_idev, _format, _arg...)
157 bool zpa2326_isreg_writeable(struct device *dev, unsigned int reg)
160 case ZPA2326_REF_P_XL_REG:
161 case ZPA2326_REF_P_L_REG:
162 case ZPA2326_REF_P_H_REG:
163 case ZPA2326_RES_CONF_REG:
164 case ZPA2326_CTRL_REG0_REG:
165 case ZPA2326_CTRL_REG1_REG:
166 case ZPA2326_CTRL_REG2_REG:
167 case ZPA2326_CTRL_REG3_REG:
168 case ZPA2326_THS_P_LOW_REG:
169 case ZPA2326_THS_P_HIGH_REG:
176 EXPORT_SYMBOL_GPL(zpa2326_isreg_writeable);
178 bool zpa2326_isreg_readable(struct device *dev, unsigned int reg)
181 case ZPA2326_REF_P_XL_REG:
182 case ZPA2326_REF_P_L_REG:
183 case ZPA2326_REF_P_H_REG:
184 case ZPA2326_DEVICE_ID_REG:
185 case ZPA2326_RES_CONF_REG:
186 case ZPA2326_CTRL_REG0_REG:
187 case ZPA2326_CTRL_REG1_REG:
188 case ZPA2326_CTRL_REG2_REG:
189 case ZPA2326_CTRL_REG3_REG:
190 case ZPA2326_INT_SOURCE_REG:
191 case ZPA2326_THS_P_LOW_REG:
192 case ZPA2326_THS_P_HIGH_REG:
193 case ZPA2326_STATUS_REG:
194 case ZPA2326_PRESS_OUT_XL_REG:
195 case ZPA2326_PRESS_OUT_L_REG:
196 case ZPA2326_PRESS_OUT_H_REG:
197 case ZPA2326_TEMP_OUT_L_REG:
198 case ZPA2326_TEMP_OUT_H_REG:
205 EXPORT_SYMBOL_GPL(zpa2326_isreg_readable);
207 bool zpa2326_isreg_precious(struct device *dev, unsigned int reg)
210 case ZPA2326_INT_SOURCE_REG:
211 case ZPA2326_PRESS_OUT_H_REG:
218 EXPORT_SYMBOL_GPL(zpa2326_isreg_precious);
221 * zpa2326_enable_device() - Enable device, i.e. get out of low power mode.
222 * @indio_dev: The IIO device associated with the hardware to enable.
224 * Required to access complete register space and to perform any sampling
225 * or control operations.
227 * Return: Zero when successful, a negative error code otherwise.
229 static int zpa2326_enable_device(const struct iio_dev *indio_dev)
233 err = regmap_write(((struct zpa2326_private *)
234 iio_priv(indio_dev))->regmap,
235 ZPA2326_CTRL_REG0_REG, ZPA2326_CTRL_REG0_ENABLE);
237 zpa2326_err(indio_dev, "failed to enable device (%d)", err);
241 zpa2326_dbg(indio_dev, "enabled");
247 * zpa2326_sleep() - Disable device, i.e. switch to low power mode.
248 * @indio_dev: The IIO device associated with the hardware to disable.
250 * Only %ZPA2326_DEVICE_ID_REG and %ZPA2326_CTRL_REG0_REG registers may be
251 * accessed once device is in the disabled state.
253 * Return: Zero when successful, a negative error code otherwise.
255 static int zpa2326_sleep(const struct iio_dev *indio_dev)
259 err = regmap_write(((struct zpa2326_private *)
260 iio_priv(indio_dev))->regmap,
261 ZPA2326_CTRL_REG0_REG, 0);
263 zpa2326_err(indio_dev, "failed to sleep (%d)", err);
267 zpa2326_dbg(indio_dev, "sleeping");
273 * zpa2326_reset_device() - Reset device to default hardware state.
274 * @indio_dev: The IIO device associated with the hardware to reset.
276 * Disable sampling and empty hardware FIFO.
277 * Device must be enabled before reset, i.e. not in low power mode.
279 * Return: Zero when successful, a negative error code otherwise.
281 static int zpa2326_reset_device(const struct iio_dev *indio_dev)
285 err = regmap_write(((struct zpa2326_private *)
286 iio_priv(indio_dev))->regmap,
287 ZPA2326_CTRL_REG2_REG, ZPA2326_CTRL_REG2_SWRESET);
289 zpa2326_err(indio_dev, "failed to reset device (%d)", err);
293 usleep_range(ZPA2326_TPUP_USEC_MIN, ZPA2326_TPUP_USEC_MAX);
295 zpa2326_dbg(indio_dev, "reset");
301 * zpa2326_start_oneshot() - Start a single sampling cycle, i.e. in one shot
303 * @indio_dev: The IIO device associated with the sampling hardware.
305 * Device must have been previously enabled and configured for one shot mode.
306 * Device will be switched back to low power mode at end of cycle.
308 * Return: Zero when successful, a negative error code otherwise.
310 static int zpa2326_start_oneshot(const struct iio_dev *indio_dev)
314 err = regmap_write(((struct zpa2326_private *)
315 iio_priv(indio_dev))->regmap,
316 ZPA2326_CTRL_REG0_REG,
317 ZPA2326_CTRL_REG0_ENABLE |
318 ZPA2326_CTRL_REG0_ONE_SHOT);
320 zpa2326_err(indio_dev, "failed to start one shot cycle (%d)",
325 zpa2326_dbg(indio_dev, "one shot cycle started");
331 * zpa2326_power_on() - Power on device to allow subsequent configuration.
332 * @indio_dev: The IIO device associated with the sampling hardware.
333 * @private: Internal private state related to @indio_dev.
335 * Sampling will be disabled, preventing strange things from happening in our
336 * back. Hardware FIFO content will be cleared.
337 * When successful, device will be left in the enabled state to allow further
340 * Return: Zero when successful, a negative error code otherwise.
342 static int zpa2326_power_on(const struct iio_dev *indio_dev,
343 const struct zpa2326_private *private)
347 err = regulator_enable(private->vref);
351 err = regulator_enable(private->vdd);
355 zpa2326_dbg(indio_dev, "powered on");
357 err = zpa2326_enable_device(indio_dev);
361 err = zpa2326_reset_device(indio_dev);
368 zpa2326_sleep(indio_dev);
370 regulator_disable(private->vdd);
372 regulator_disable(private->vref);
374 zpa2326_dbg(indio_dev, "powered off");
380 * zpa2326_power_off() - Power off device, i.e. disable attached power
382 * @indio_dev: The IIO device associated with the sampling hardware.
383 * @private: Internal private state related to @indio_dev.
385 * Return: Zero when successful, a negative error code otherwise.
387 static void zpa2326_power_off(const struct iio_dev *indio_dev,
388 const struct zpa2326_private *private)
390 regulator_disable(private->vdd);
391 regulator_disable(private->vref);
393 zpa2326_dbg(indio_dev, "powered off");
397 * zpa2326_config_oneshot() - Setup device for one shot / on demand mode.
398 * @indio_dev: The IIO device associated with the sampling hardware.
399 * @irq: Optional interrupt line the hardware uses to notify new data
400 * samples are ready. Negative or zero values indicate no interrupts
401 * are available, meaning polling is required.
403 * Output Data Rate is configured for the highest possible rate so that
404 * conversion time and power consumption are reduced to a minimum.
405 * Note that hardware internal averaging machinery (not implemented in this
406 * driver) is not applicable in this mode.
408 * Device must have been previously enabled before calling
409 * zpa2326_config_oneshot().
411 * Return: Zero when successful, a negative error code otherwise.
413 static int zpa2326_config_oneshot(const struct iio_dev *indio_dev,
416 struct regmap *regs = ((struct zpa2326_private *)
417 iio_priv(indio_dev))->regmap;
418 const struct zpa2326_frequency *freq = zpa2326_highest_frequency();
421 /* Setup highest available Output Data Rate for one shot mode. */
422 err = regmap_write(regs, ZPA2326_CTRL_REG3_REG, freq->odr);
427 /* Request interrupt when new sample is available. */
428 err = regmap_write(regs, ZPA2326_CTRL_REG1_REG,
429 (u8)~ZPA2326_CTRL_REG1_MASK_DATA_READY);
432 dev_err(indio_dev->dev.parent,
433 "failed to setup one shot mode (%d)", err);
438 zpa2326_dbg(indio_dev, "one shot mode setup @%dHz", freq->hz);
444 * zpa2326_clear_fifo() - Clear remaining entries in hardware FIFO.
445 * @indio_dev: The IIO device associated with the sampling hardware.
446 * @min_count: Number of samples present within hardware FIFO.
448 * @min_count argument is a hint corresponding to the known minimum number of
449 * samples currently living in the FIFO. This allows to reduce the number of bus
450 * accesses by skipping status register read operation as long as we know for
451 * sure there are still entries left.
453 * Return: Zero when successful, a negative error code otherwise.
455 static int zpa2326_clear_fifo(const struct iio_dev *indio_dev,
456 unsigned int min_count)
458 struct regmap *regs = ((struct zpa2326_private *)
459 iio_priv(indio_dev))->regmap;
465 * No hint: read status register to determine whether FIFO is
468 err = regmap_read(regs, ZPA2326_STATUS_REG, &val);
473 if (val & ZPA2326_STATUS_FIFO_E)
474 /* Fifo is empty: nothing to trash. */
481 * A single fetch from pressure MSB register is enough to pop
482 * values out of FIFO.
484 err = regmap_read(regs, ZPA2326_PRESS_OUT_H_REG, &val);
490 * We know for sure there are at least min_count entries
491 * left in FIFO. Skip status register read.
497 err = regmap_read(regs, ZPA2326_STATUS_REG, &val);
501 } while (!(val & ZPA2326_STATUS_FIFO_E));
503 zpa2326_dbg(indio_dev, "FIFO cleared");
508 zpa2326_err(indio_dev, "failed to clear FIFO (%d)", err);
514 * zpa2326_dequeue_pressure() - Retrieve the most recent pressure sample from
516 * @indio_dev: The IIO device associated with the sampling hardware.
517 * @pressure: Sampled pressure output.
519 * Note that ZPA2326 hardware FIFO stores pressure samples only.
521 * Return: Zero when successful, a negative error code otherwise.
523 static int zpa2326_dequeue_pressure(const struct iio_dev *indio_dev,
526 struct regmap *regs = ((struct zpa2326_private *)
527 iio_priv(indio_dev))->regmap;
532 err = regmap_read(regs, ZPA2326_STATUS_REG, &val);
538 if (val & ZPA2326_STATUS_P_OR) {
540 * Fifo overrun : first sample dequeued from FIFO is the
543 zpa2326_warn(indio_dev, "FIFO overflow");
545 err = regmap_bulk_read(regs, ZPA2326_PRESS_OUT_XL_REG, pressure,
550 #define ZPA2326_FIFO_DEPTH (16U)
551 /* Hardware FIFO may hold no more than 16 pressure samples. */
552 return zpa2326_clear_fifo(indio_dev, ZPA2326_FIFO_DEPTH - 1);
556 * Fifo has not overflown : retrieve newest sample. We need to pop
557 * values out until FIFO is empty : last fetched pressure is the newest.
558 * In nominal cases, we should find a single queued sample only.
561 err = regmap_bulk_read(regs, ZPA2326_PRESS_OUT_XL_REG, pressure,
566 err = regmap_read(regs, ZPA2326_STATUS_REG, &val);
571 } while (!(val & ZPA2326_STATUS_FIFO_E));
575 * Samples were pushed by hardware during previous rounds but we
576 * didn't consume them fast enough: inform user.
578 zpa2326_dbg(indio_dev, "cleared %d FIFO entries", cleared);
584 * zpa2326_fill_sample_buffer() - Enqueue new channel samples to IIO buffer.
585 * @indio_dev: The IIO device associated with the sampling hardware.
586 * @private: Internal private state related to @indio_dev.
588 * Return: Zero when successful, a negative error code otherwise.
590 static int zpa2326_fill_sample_buffer(struct iio_dev *indio_dev,
591 const struct zpa2326_private *private)
600 if (test_bit(0, indio_dev->active_scan_mask)) {
601 /* Get current pressure from hardware FIFO. */
602 err = zpa2326_dequeue_pressure(indio_dev, &sample.pressure);
604 zpa2326_warn(indio_dev, "failed to fetch pressure (%d)",
610 if (test_bit(1, indio_dev->active_scan_mask)) {
611 /* Get current temperature. */
612 err = regmap_bulk_read(private->regmap, ZPA2326_TEMP_OUT_L_REG,
613 &sample.temperature, 2);
615 zpa2326_warn(indio_dev,
616 "failed to fetch temperature (%d)", err);
622 * Now push samples using timestamp stored either :
623 * - by hardware interrupt handler if interrupt is available: see
624 * zpa2326_handle_irq(),
625 * - or oneshot completion polling machinery : see
626 * zpa2326_trigger_handler().
628 zpa2326_dbg(indio_dev, "filling raw samples buffer");
630 iio_push_to_buffers_with_timestamp(indio_dev, &sample,
637 static int zpa2326_runtime_suspend(struct device *parent)
639 const struct iio_dev *indio_dev = dev_get_drvdata(parent);
641 if (pm_runtime_autosuspend_expiration(parent))
642 /* Userspace changed autosuspend delay. */
645 zpa2326_power_off(indio_dev, iio_priv(indio_dev));
650 static int zpa2326_runtime_resume(struct device *parent)
652 const struct iio_dev *indio_dev = dev_get_drvdata(parent);
654 return zpa2326_power_on(indio_dev, iio_priv(indio_dev));
657 const struct dev_pm_ops zpa2326_pm_ops = {
658 SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
659 pm_runtime_force_resume)
660 SET_RUNTIME_PM_OPS(zpa2326_runtime_suspend, zpa2326_runtime_resume,
663 EXPORT_SYMBOL_GPL(zpa2326_pm_ops);
666 * zpa2326_resume() - Request the PM layer to power supply the device.
667 * @indio_dev: The IIO device associated with the sampling hardware.
670 * < 0 - a negative error code meaning failure ;
671 * 0 - success, device has just been powered up ;
672 * 1 - success, device was already powered.
674 static int zpa2326_resume(const struct iio_dev *indio_dev)
678 err = pm_runtime_get_sync(indio_dev->dev.parent);
684 * Device was already power supplied: get it out of low power
685 * mode and inform caller.
687 zpa2326_enable_device(indio_dev);
691 /* Inform caller device has just been brought back to life. */
696 * zpa2326_suspend() - Schedule a power down using autosuspend feature of PM
698 * @indio_dev: The IIO device associated with the sampling hardware.
700 * Device is switched to low power mode at first to save power even when
701 * attached regulator is a "dummy" one.
703 static void zpa2326_suspend(struct iio_dev *indio_dev)
705 struct device *parent = indio_dev->dev.parent;
707 zpa2326_sleep(indio_dev);
709 pm_runtime_mark_last_busy(parent);
710 pm_runtime_put_autosuspend(parent);
713 static void zpa2326_init_runtime(struct device *parent)
715 pm_runtime_get_noresume(parent);
716 pm_runtime_set_active(parent);
717 pm_runtime_enable(parent);
718 pm_runtime_set_autosuspend_delay(parent, 1000);
719 pm_runtime_use_autosuspend(parent);
720 pm_runtime_mark_last_busy(parent);
721 pm_runtime_put_autosuspend(parent);
724 static void zpa2326_fini_runtime(struct device *parent)
726 pm_runtime_disable(parent);
727 pm_runtime_set_suspended(parent);
729 #else /* !CONFIG_PM */
730 static int zpa2326_resume(const struct iio_dev *indio_dev)
732 zpa2326_enable_device(indio_dev);
737 static void zpa2326_suspend(struct iio_dev *indio_dev)
739 zpa2326_sleep(indio_dev);
742 #define zpa2326_init_runtime(_parent)
743 #define zpa2326_fini_runtime(_parent)
744 #endif /* !CONFIG_PM */
747 * zpa2326_handle_irq() - Process hardware interrupts.
748 * @irq: Interrupt line the hardware uses to notify new data has arrived.
749 * @data: The IIO device associated with the sampling hardware.
751 * Timestamp buffered samples as soon as possible then schedule threaded bottom
754 * Return: Always successful.
756 static irqreturn_t zpa2326_handle_irq(int irq, void *data)
758 struct iio_dev *indio_dev = (struct iio_dev *)data;
760 if (iio_buffer_enabled(indio_dev)) {
761 /* Timestamping needed for buffered sampling only. */
762 ((struct zpa2326_private *)
763 iio_priv(indio_dev))->timestamp = iio_get_time_ns(indio_dev);
766 return IRQ_WAKE_THREAD;
770 * zpa2326_handle_threaded_irq() - Interrupt bottom-half handler.
771 * @irq: Interrupt line the hardware uses to notify new data has arrived.
772 * @data: The IIO device associated with the sampling hardware.
774 * Mainly ensures interrupt is caused by a real "new sample available"
775 * condition. This relies upon the ability to perform blocking / sleeping bus
776 * accesses to slave's registers. This is why zpa2326_handle_threaded_irq() is
777 * called from within a thread, i.e. not called from hard interrupt context.
779 * When device is using its own internal hardware trigger in continuous sampling
780 * mode, data are available into hardware FIFO once interrupt has occurred. All
781 * we have to do is to dispatch the trigger, which in turn will fetch data and
784 * When not using its own internal hardware trigger, the device has been
785 * configured in one-shot mode either by an external trigger or the IIO read_raw
786 * hook. This means one of the latter is currently waiting for sampling
787 * completion, in which case we must simply wake it up.
789 * See zpa2326_trigger_handler().
792 * %IRQ_NONE - no consistent interrupt happened ;
793 * %IRQ_HANDLED - there was new samples available.
795 static irqreturn_t zpa2326_handle_threaded_irq(int irq, void *data)
797 struct iio_dev *indio_dev = (struct iio_dev *)data;
798 struct zpa2326_private *priv = iio_priv(indio_dev);
801 irqreturn_t ret = IRQ_NONE;
804 * Are we using our own internal trigger in triggered buffer mode, i.e.,
805 * currently working in continuous sampling mode ?
807 cont = (iio_buffer_enabled(indio_dev) &&
808 iio_trigger_using_own(indio_dev));
811 * Device works according to a level interrupt scheme: reading interrupt
812 * status de-asserts interrupt line.
814 priv->result = regmap_read(priv->regmap, ZPA2326_INT_SOURCE_REG, &val);
815 if (priv->result < 0) {
822 /* Data ready is the only interrupt source we requested. */
823 if (!(val & ZPA2326_INT_SOURCE_DATA_READY)) {
825 * Interrupt happened but no new sample available: likely caused
826 * by spurious interrupts, in which case, returning IRQ_NONE
827 * allows to benefit from the generic spurious interrupts
830 zpa2326_warn(indio_dev, "unexpected interrupt status %02x",
836 priv->result = -ENODATA;
840 /* New sample available: dispatch internal trigger consumers. */
841 iio_trigger_poll_chained(priv->trigger);
845 * Internal hardware trigger has been scheduled above : it will
846 * fetch data on its own.
854 * Wake up direct or externaly triggered buffer mode waiters: see
855 * zpa2326_sample_oneshot() and zpa2326_trigger_handler().
857 complete(&priv->data_ready);
863 * zpa2326_wait_oneshot_completion() - Wait for oneshot data ready interrupt.
864 * @indio_dev: The IIO device associated with the sampling hardware.
865 * @private: Internal private state related to @indio_dev.
867 * Return: Zero when successful, a negative error code otherwise.
869 static int zpa2326_wait_oneshot_completion(const struct iio_dev *indio_dev,
870 struct zpa2326_private *private)
875 zpa2326_dbg(indio_dev, "waiting for one shot completion interrupt");
877 ret = wait_for_completion_interruptible_timeout(
878 &private->data_ready, ZPA2326_CONVERSION_JIFFIES);
881 * Interrupt handler completed before timeout: return operation
884 return private->result;
886 /* Clear all interrupts just to be sure. */
887 regmap_read(private->regmap, ZPA2326_INT_SOURCE_REG, &val);
893 if (ret != -ERESTARTSYS)
894 zpa2326_warn(indio_dev, "no one shot interrupt occurred (%d)",
900 static int zpa2326_init_managed_irq(struct device *parent,
901 struct iio_dev *indio_dev,
902 struct zpa2326_private *private,
911 * Platform declared no interrupt line: device will be polled
912 * for data availability.
914 dev_info(parent, "no interrupt found, running in polling mode");
918 init_completion(&private->data_ready);
920 /* Request handler to be scheduled into threaded interrupt context. */
921 err = devm_request_threaded_irq(parent, irq, zpa2326_handle_irq,
922 zpa2326_handle_threaded_irq,
923 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
924 dev_name(parent), indio_dev);
926 dev_err(parent, "failed to request interrupt %d (%d)", irq,
931 dev_info(parent, "using interrupt %d", irq);
937 * zpa2326_poll_oneshot_completion() - Actively poll for one shot data ready.
938 * @indio_dev: The IIO device associated with the sampling hardware.
940 * Loop over registers content to detect end of sampling cycle. Used when DT
941 * declared no valid interrupt lines.
943 * Return: Zero when successful, a negative error code otherwise.
945 static int zpa2326_poll_oneshot_completion(const struct iio_dev *indio_dev)
947 unsigned long tmout = jiffies + ZPA2326_CONVERSION_JIFFIES;
948 struct regmap *regs = ((struct zpa2326_private *)
949 iio_priv(indio_dev))->regmap;
953 zpa2326_dbg(indio_dev, "polling for one shot completion");
956 * At least, 100 ms is needed for the device to complete its one-shot
959 if (msleep_interruptible(100))
962 /* Poll for conversion completion in hardware. */
964 err = regmap_read(regs, ZPA2326_CTRL_REG0_REG, &val);
968 if (!(val & ZPA2326_CTRL_REG0_ONE_SHOT))
969 /* One-shot bit self clears at conversion end. */
972 if (time_after(jiffies, tmout)) {
973 /* Prevent from waiting forever : let's time out. */
978 usleep_range(10000, 20000);
982 * In oneshot mode, pressure sample availability guarantees that
983 * temperature conversion has also completed : just check pressure
984 * status bit to keep things simple.
986 err = regmap_read(regs, ZPA2326_STATUS_REG, &val);
990 if (!(val & ZPA2326_STATUS_P_DA)) {
991 /* No sample available. */
999 zpa2326_warn(indio_dev, "failed to poll one shot completion (%d)", err);
1005 * zpa2326_fetch_raw_sample() - Retrieve a raw sample and convert it to CPU
1007 * @indio_dev: The IIO device associated with the sampling hardware.
1008 * @type: Type of measurement / channel to fetch from.
1009 * @value: Sample output.
1011 * Return: Zero when successful, a negative error code otherwise.
1013 static int zpa2326_fetch_raw_sample(const struct iio_dev *indio_dev,
1014 enum iio_chan_type type,
1017 struct regmap *regs = ((struct zpa2326_private *)
1018 iio_priv(indio_dev))->regmap;
1023 zpa2326_dbg(indio_dev, "fetching raw pressure sample");
1025 err = regmap_bulk_read(regs, ZPA2326_PRESS_OUT_XL_REG, value,
1028 zpa2326_warn(indio_dev, "failed to fetch pressure (%d)",
1033 /* Pressure is a 24 bits wide little-endian unsigned int. */
1034 *value = (((u8 *)value)[2] << 16) | (((u8 *)value)[1] << 8) |
1040 zpa2326_dbg(indio_dev, "fetching raw temperature sample");
1042 err = regmap_bulk_read(regs, ZPA2326_TEMP_OUT_L_REG, value, 2);
1044 zpa2326_warn(indio_dev,
1045 "failed to fetch temperature (%d)", err);
1049 /* Temperature is a 16 bits wide little-endian signed int. */
1050 *value = (int)le16_to_cpup((__le16 *)value);
1060 * zpa2326_sample_oneshot() - Perform a complete one shot sampling cycle.
1061 * @indio_dev: The IIO device associated with the sampling hardware.
1062 * @type: Type of measurement / channel to fetch from.
1063 * @value: Sample output.
1065 * Return: Zero when successful, a negative error code otherwise.
1067 static int zpa2326_sample_oneshot(struct iio_dev *indio_dev,
1068 enum iio_chan_type type,
1072 struct zpa2326_private *priv;
1074 ret = iio_device_claim_direct_mode(indio_dev);
1078 ret = zpa2326_resume(indio_dev);
1082 priv = iio_priv(indio_dev);
1086 * We were already power supplied. Just clear hardware FIFO to
1087 * get rid of samples acquired during previous rounds (if any).
1088 * Sampling operation always generates both temperature and
1089 * pressure samples. The latter are always enqueued into
1090 * hardware FIFO. This may lead to situations were pressure
1091 * samples still sit into FIFO when previous cycle(s) fetched
1092 * temperature data only.
1093 * Hence, we need to clear hardware FIFO content to prevent from
1094 * getting outdated values at the end of current cycle.
1096 if (type == IIO_PRESSURE) {
1097 ret = zpa2326_clear_fifo(indio_dev, 0);
1103 * We have just been power supplied, i.e. device is in default
1104 * "out of reset" state, meaning we need to reconfigure it
1107 ret = zpa2326_config_oneshot(indio_dev, priv->irq);
1112 /* Start a sampling cycle in oneshot mode. */
1113 ret = zpa2326_start_oneshot(indio_dev);
1117 /* Wait for sampling cycle to complete. */
1119 ret = zpa2326_wait_oneshot_completion(indio_dev, priv);
1121 ret = zpa2326_poll_oneshot_completion(indio_dev);
1126 /* Retrieve raw sample value and convert it to CPU endianness. */
1127 ret = zpa2326_fetch_raw_sample(indio_dev, type, value);
1130 zpa2326_suspend(indio_dev);
1132 iio_device_release_direct_mode(indio_dev);
1138 * zpa2326_trigger_handler() - Perform an IIO buffered sampling round in one
1140 * @irq: The software interrupt assigned to @data
1141 * @data: The IIO poll function dispatched by external trigger our device is
1144 * Bottom-half handler called by the IIO trigger to which our device is
1145 * currently attached. Allows us to synchronize this device buffered sampling
1146 * either with external events (such as timer expiration, external device sample
1147 * ready, etc...) or with its own interrupt (internal hardware trigger).
1149 * When using an external trigger, basically run the same sequence of operations
1150 * as for zpa2326_sample_oneshot() with the following hereafter. Hardware FIFO
1151 * is not cleared since already done at buffering enable time and samples
1152 * dequeueing always retrieves the most recent value.
1154 * Otherwise, when internal hardware trigger has dispatched us, just fetch data
1155 * from hardware FIFO.
1157 * Fetched data will pushed unprocessed to IIO buffer since samples conversion
1158 * is delegated to userspace in buffered mode (endianness, etc...).
1161 * %IRQ_NONE - no consistent interrupt happened ;
1162 * %IRQ_HANDLED - there was new samples available.
1164 static irqreturn_t zpa2326_trigger_handler(int irq, void *data)
1166 struct iio_dev *indio_dev = ((struct iio_poll_func *)
1168 struct zpa2326_private *priv = iio_priv(indio_dev);
1172 * We have been dispatched, meaning we are in triggered buffer mode.
1173 * Using our own internal trigger implies we are currently in continuous
1174 * hardware sampling mode.
1176 cont = iio_trigger_using_own(indio_dev);
1179 /* On demand sampling : start a one shot cycle. */
1180 if (zpa2326_start_oneshot(indio_dev))
1183 /* Wait for sampling cycle to complete. */
1184 if (priv->irq <= 0) {
1185 /* No interrupt available: poll for completion. */
1186 if (zpa2326_poll_oneshot_completion(indio_dev))
1189 /* Only timestamp sample once it is ready. */
1190 priv->timestamp = iio_get_time_ns(indio_dev);
1192 /* Interrupt handlers will timestamp for us. */
1193 if (zpa2326_wait_oneshot_completion(indio_dev, priv))
1198 /* Enqueue to IIO buffer / userspace. */
1199 zpa2326_fill_sample_buffer(indio_dev, priv);
1203 /* Don't switch to low power if sampling continuously. */
1204 zpa2326_sleep(indio_dev);
1206 /* Inform attached trigger we are done. */
1207 iio_trigger_notify_done(indio_dev->trig);
1213 * zpa2326_preenable_buffer() - Prepare device for configuring triggered
1216 * @indio_dev: The IIO device associated with the sampling hardware.
1218 * Basically power up device.
1219 * Called with IIO device's lock held.
1221 * Return: Zero when successful, a negative error code otherwise.
1223 static int zpa2326_preenable_buffer(struct iio_dev *indio_dev)
1225 int ret = zpa2326_resume(indio_dev);
1230 /* Tell zpa2326_postenable_buffer() if we have just been powered on. */
1231 ((struct zpa2326_private *)
1232 iio_priv(indio_dev))->waken = iio_priv(indio_dev);
1238 * zpa2326_postenable_buffer() - Configure device for triggered sampling.
1239 * @indio_dev: The IIO device associated with the sampling hardware.
1241 * Basically setup one-shot mode if plugging external trigger.
1242 * Otherwise, let internal trigger configure continuous sampling :
1243 * see zpa2326_set_trigger_state().
1245 * If an error is returned, IIO layer will call our postdisable hook for us,
1246 * i.e. no need to explicitly power device off here.
1247 * Called with IIO device's lock held.
1249 * Called with IIO device's lock held.
1251 * Return: Zero when successful, a negative error code otherwise.
1253 static int zpa2326_postenable_buffer(struct iio_dev *indio_dev)
1255 const struct zpa2326_private *priv = iio_priv(indio_dev);
1260 * We were already power supplied. Just clear hardware FIFO to
1261 * get rid of samples acquired during previous rounds (if any).
1263 err = zpa2326_clear_fifo(indio_dev, 0);
1268 if (!iio_trigger_using_own(indio_dev) && priv->waken) {
1270 * We are using an external trigger and we have just been
1271 * powered up: reconfigure one-shot mode.
1273 err = zpa2326_config_oneshot(indio_dev, priv->irq);
1278 /* Plug our own trigger event handler. */
1279 err = iio_triggered_buffer_postenable(indio_dev);
1286 zpa2326_err(indio_dev, "failed to enable buffering (%d)", err);
1291 static int zpa2326_postdisable_buffer(struct iio_dev *indio_dev)
1293 zpa2326_suspend(indio_dev);
1298 static const struct iio_buffer_setup_ops zpa2326_buffer_setup_ops = {
1299 .preenable = zpa2326_preenable_buffer,
1300 .postenable = zpa2326_postenable_buffer,
1301 .predisable = iio_triggered_buffer_predisable,
1302 .postdisable = zpa2326_postdisable_buffer
1306 * zpa2326_set_trigger_state() - Start / stop continuous sampling.
1307 * @trig: The trigger being attached to IIO device associated with the sampling
1309 * @state: Tell whether to start (true) or stop (false)
1311 * Basically enable / disable hardware continuous sampling mode.
1313 * Called with IIO device's lock held at postenable() or predisable() time.
1315 * Return: Zero when successful, a negative error code otherwise.
1317 static int zpa2326_set_trigger_state(struct iio_trigger *trig, bool state)
1319 const struct iio_dev *indio_dev = dev_get_drvdata(
1321 const struct zpa2326_private *priv = iio_priv(indio_dev);
1326 * Switch trigger off : in case of failure, interrupt is left
1327 * disabled in order to prevent handler from accessing released
1333 * As device is working in continuous mode, handlers may be
1334 * accessing resources we are currently freeing...
1335 * Prevent this by disabling interrupt handlers and ensure
1336 * the device will generate no more interrupts unless explicitly
1337 * required to, i.e. by restoring back to default one shot mode.
1339 disable_irq(priv->irq);
1342 * Disable continuous sampling mode to restore settings for
1343 * one shot / direct sampling operations.
1345 err = regmap_write(priv->regmap, ZPA2326_CTRL_REG3_REG,
1346 zpa2326_highest_frequency()->odr);
1351 * Now that device won't generate interrupts on its own,
1352 * acknowledge any currently active interrupts (may happen on
1353 * rare occasions while stopping continuous mode).
1355 err = regmap_read(priv->regmap, ZPA2326_INT_SOURCE_REG, &val);
1360 * Re-enable interrupts only if we can guarantee the device will
1361 * generate no more interrupts to prevent handlers from
1362 * accessing released resources.
1364 enable_irq(priv->irq);
1366 zpa2326_dbg(indio_dev, "continuous mode stopped");
1369 * Switch trigger on : start continuous sampling at required
1374 /* Enable interrupt if getting out of reset. */
1375 err = regmap_write(priv->regmap, ZPA2326_CTRL_REG1_REG,
1377 ~ZPA2326_CTRL_REG1_MASK_DATA_READY);
1382 /* Enable continuous sampling at specified frequency. */
1383 err = regmap_write(priv->regmap, ZPA2326_CTRL_REG3_REG,
1384 ZPA2326_CTRL_REG3_ENABLE_MEAS |
1385 priv->frequency->odr);
1389 zpa2326_dbg(indio_dev, "continuous mode setup @%dHz",
1390 priv->frequency->hz);
1396 static const struct iio_trigger_ops zpa2326_trigger_ops = {
1397 .owner = THIS_MODULE,
1398 .set_trigger_state = zpa2326_set_trigger_state,
1402 * zpa2326_init_trigger() - Create an interrupt driven / hardware trigger
1403 * allowing to notify external devices a new sample is
1405 * @parent: Hardware sampling device @indio_dev is a child of.
1406 * @indio_dev: The IIO device associated with the sampling hardware.
1407 * @private: Internal private state related to @indio_dev.
1408 * @irq: Optional interrupt line the hardware uses to notify new data
1409 * samples are ready. Negative or zero values indicate no interrupts
1410 * are available, meaning polling is required.
1412 * Only relevant when DT declares a valid interrupt line.
1414 * Return: Zero when successful, a negative error code otherwise.
1416 static int zpa2326_init_managed_trigger(struct device *parent,
1417 struct iio_dev *indio_dev,
1418 struct zpa2326_private *private,
1421 struct iio_trigger *trigger;
1427 trigger = devm_iio_trigger_alloc(parent, "%s-dev%d",
1428 indio_dev->name, indio_dev->id);
1433 trigger->dev.parent = parent;
1434 trigger->ops = &zpa2326_trigger_ops;
1436 private->trigger = trigger;
1438 /* Register to triggers space. */
1439 ret = devm_iio_trigger_register(parent, trigger);
1441 dev_err(parent, "failed to register hardware trigger (%d)",
1447 static int zpa2326_get_frequency(const struct iio_dev *indio_dev)
1449 return ((struct zpa2326_private *)iio_priv(indio_dev))->frequency->hz;
1452 static int zpa2326_set_frequency(struct iio_dev *indio_dev, int hz)
1454 struct zpa2326_private *priv = iio_priv(indio_dev);
1458 /* Check if requested frequency is supported. */
1459 for (freq = 0; freq < ARRAY_SIZE(zpa2326_sampling_frequencies); freq++)
1460 if (zpa2326_sampling_frequencies[freq].hz == hz)
1462 if (freq == ARRAY_SIZE(zpa2326_sampling_frequencies))
1465 /* Don't allow changing frequency if buffered sampling is ongoing. */
1466 err = iio_device_claim_direct_mode(indio_dev);
1470 priv->frequency = &zpa2326_sampling_frequencies[freq];
1472 iio_device_release_direct_mode(indio_dev);
1477 /* Expose supported hardware sampling frequencies (Hz) through sysfs. */
1478 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1 5 11 23");
1480 static struct attribute *zpa2326_attributes[] = {
1481 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
1485 static const struct attribute_group zpa2326_attribute_group = {
1486 .attrs = zpa2326_attributes,
1489 static int zpa2326_read_raw(struct iio_dev *indio_dev,
1490 struct iio_chan_spec const *chan,
1496 case IIO_CHAN_INFO_RAW:
1497 return zpa2326_sample_oneshot(indio_dev, chan->type, val);
1499 case IIO_CHAN_INFO_SCALE:
1500 switch (chan->type) {
1503 * Pressure resolution is 1/64 Pascal. Scale to kPascal
1504 * as required by IIO ABI.
1508 return IIO_VAL_FRACTIONAL;
1512 * Temperature follows the equation:
1513 * Temp[degC] = Tempcode * 0.00649 - 176.83
1515 * Tempcode is composed the raw sampled 16 bits.
1517 * Hence, to produce a temperature in milli-degrees
1518 * Celsius according to IIO ABI, we need to apply the
1519 * following equation to raw samples:
1520 * Temp[milli degC] = (Tempcode + Offset) * Scale
1522 * Offset = -176.83 / 0.00649
1523 * Scale = 0.00649 * 1000
1527 return IIO_VAL_INT_PLUS_MICRO;
1533 case IIO_CHAN_INFO_OFFSET:
1534 switch (chan->type) {
1538 return IIO_VAL_FRACTIONAL;
1544 case IIO_CHAN_INFO_SAMP_FREQ:
1545 *val = zpa2326_get_frequency(indio_dev);
1553 static int zpa2326_write_raw(struct iio_dev *indio_dev,
1554 const struct iio_chan_spec *chan,
1559 if ((mask != IIO_CHAN_INFO_SAMP_FREQ) || val2)
1562 return zpa2326_set_frequency(indio_dev, val);
1565 static const struct iio_chan_spec zpa2326_channels[] = {
1567 .type = IIO_PRESSURE,
1573 .endianness = IIO_LE,
1575 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
1576 BIT(IIO_CHAN_INFO_SCALE),
1577 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
1586 .endianness = IIO_LE,
1588 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
1589 BIT(IIO_CHAN_INFO_SCALE) |
1590 BIT(IIO_CHAN_INFO_OFFSET),
1591 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
1593 [2] = IIO_CHAN_SOFT_TIMESTAMP(2),
1596 static const struct iio_info zpa2326_info = {
1597 .driver_module = THIS_MODULE,
1598 .attrs = &zpa2326_attribute_group,
1599 .read_raw = zpa2326_read_raw,
1600 .write_raw = zpa2326_write_raw,
1603 static struct iio_dev *zpa2326_create_managed_iiodev(struct device *device,
1605 struct regmap *regmap)
1607 struct iio_dev *indio_dev;
1609 /* Allocate space to hold IIO device internal state. */
1610 indio_dev = devm_iio_device_alloc(device,
1611 sizeof(struct zpa2326_private));
1615 /* Setup for userspace synchronous on demand sampling. */
1616 indio_dev->modes = INDIO_DIRECT_MODE;
1617 indio_dev->dev.parent = device;
1618 indio_dev->channels = zpa2326_channels;
1619 indio_dev->num_channels = ARRAY_SIZE(zpa2326_channels);
1620 indio_dev->name = name;
1621 indio_dev->info = &zpa2326_info;
1626 int zpa2326_probe(struct device *parent,
1630 struct regmap *regmap)
1632 struct iio_dev *indio_dev;
1633 struct zpa2326_private *priv;
1637 indio_dev = zpa2326_create_managed_iiodev(parent, name, regmap);
1641 priv = iio_priv(indio_dev);
1643 priv->vref = devm_regulator_get(parent, "vref");
1644 if (IS_ERR(priv->vref))
1645 return PTR_ERR(priv->vref);
1647 priv->vdd = devm_regulator_get(parent, "vdd");
1648 if (IS_ERR(priv->vdd))
1649 return PTR_ERR(priv->vdd);
1651 /* Set default hardware sampling frequency to highest rate supported. */
1652 priv->frequency = zpa2326_highest_frequency();
1655 * Plug device's underlying bus abstraction : this MUST be set before
1656 * registering interrupt handlers since an interrupt might happen if
1657 * power up sequence is not properly applied.
1659 priv->regmap = regmap;
1661 err = devm_iio_triggered_buffer_setup(parent, indio_dev, NULL,
1662 zpa2326_trigger_handler,
1663 &zpa2326_buffer_setup_ops);
1667 err = zpa2326_init_managed_trigger(parent, indio_dev, priv, irq);
1671 err = zpa2326_init_managed_irq(parent, indio_dev, priv, irq);
1675 /* Power up to check device ID and perform initial hardware setup. */
1676 err = zpa2326_power_on(indio_dev, priv);
1680 /* Read id register to check we are talking to the right slave. */
1681 err = regmap_read(regmap, ZPA2326_DEVICE_ID_REG, &id);
1686 dev_err(parent, "found device with unexpected id %02x", id);
1691 err = zpa2326_config_oneshot(indio_dev, irq);
1695 /* Setup done : go sleeping. Device will be awaken upon user request. */
1696 err = zpa2326_sleep(indio_dev);
1700 dev_set_drvdata(parent, indio_dev);
1702 zpa2326_init_runtime(parent);
1704 err = iio_device_register(indio_dev);
1706 zpa2326_fini_runtime(parent);
1713 /* Put to sleep just in case power regulators are "dummy" ones. */
1714 zpa2326_sleep(indio_dev);
1716 zpa2326_power_off(indio_dev, priv);
1720 EXPORT_SYMBOL_GPL(zpa2326_probe);
1722 void zpa2326_remove(const struct device *parent)
1724 struct iio_dev *indio_dev = dev_get_drvdata(parent);
1726 iio_device_unregister(indio_dev);
1727 zpa2326_fini_runtime(indio_dev->dev.parent);
1728 zpa2326_sleep(indio_dev);
1729 zpa2326_power_off(indio_dev, iio_priv(indio_dev));
1731 EXPORT_SYMBOL_GPL(zpa2326_remove);
1733 MODULE_AUTHOR("Gregor Boirie <gregor.boirie@parrot.com>");
1734 MODULE_DESCRIPTION("Core driver for Murata ZPA2326 pressure sensor");
1735 MODULE_LICENSE("GPL v2");