2 * Mainly by David Woodhouse, somewhat modified by Jordan Crouse
4 * Copyright © 2006-2007 Red Hat, Inc.
5 * Copyright © 2006-2007 Advanced Micro Devices, Inc.
6 * Copyright © 2009 VIA Technology, Inc.
7 * Copyright (c) 2010-2011 Andres Salomon <dilinger@queued.net>
9 * This program is free software. You can redistribute it and/or
10 * modify it under the terms of version 2 of the GNU General Public
11 * License as published by the Free Software Foundation.
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 #include <linux/kernel.h>
18 #include <linux/console.h>
19 #include <linux/i2c.h>
20 #include <linux/platform_device.h>
21 #include <linux/pci.h>
22 #include <linux/pci_ids.h>
23 #include <linux/interrupt.h>
24 #include <linux/delay.h>
25 #include <linux/module.h>
26 #include <linux/backlight.h>
27 #include <linux/device.h>
28 #include <linux/uaccess.h>
29 #include <linux/ctype.h>
30 #include <linux/reboot.h>
31 #include <linux/olpc-ec.h>
35 #include "olpc_dcon.h"
37 /* Module definitions */
39 static ushort resumeline = 898;
40 module_param(resumeline, ushort, 0444);
42 static struct dcon_platform_data *pdata;
46 /* Platform devices */
47 static struct platform_device *dcon_device;
49 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
51 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
53 return i2c_smbus_write_word_data(dcon->client, reg, val);
56 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
58 return i2c_smbus_read_word_data(dcon->client, reg);
61 /* ===== API functions - these are called by a variety of users ==== */
63 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
68 ver = dcon_read(dcon, DCON_REG_ID);
69 if ((ver >> 8) != 0xDC) {
70 pr_err("DCON ID not 0xDCxx: 0x%04x instead.\n", ver);
76 pr_info("Discovered DCON version %x\n", ver & 0xFF);
77 rc = pdata->init(dcon);
79 pr_err("Unable to init.\n");
85 dev_err(&dcon->client->dev,
86 "DCON v1 is unsupported, giving up..\n");
91 /* SDRAM setup/hold time */
92 dcon_write(dcon, 0x3a, 0xc040);
93 dcon_write(dcon, DCON_REG_MEM_OPT_A, 0x0000); /* clear option bits */
94 dcon_write(dcon, DCON_REG_MEM_OPT_A,
95 MEM_DLL_CLOCK_DELAY | MEM_POWER_DOWN);
96 dcon_write(dcon, DCON_REG_MEM_OPT_B, MEM_SOFT_RESET);
98 /* Colour swizzle, AA, no passthrough, backlight */
100 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
101 MODE_CSWIZZLE | MODE_COL_AA;
103 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
106 /* Set the scanline to interrupt on during resume */
107 dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
114 * The smbus doesn't always come back due to what is believed to be
115 * hardware (power rail) bugs. For older models where this is known to
116 * occur, our solution is to attempt to wait for the bus to stabilize;
117 * if it doesn't happen, cut power to the dcon, repower it, and wait
118 * for the bus to stabilize. Rinse, repeat until we have a working
119 * smbus. For newer models, we simply BUG(); we want to know if this
120 * still happens despite the power fixes that have been made!
122 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
124 unsigned long timeout;
129 if (is_powered_down) {
131 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
133 pr_warn("unable to force dcon to power up: %d!\n", x);
136 usleep_range(10000, 11000); /* we'll be conservative */
139 pdata->bus_stabilize_wiggle();
141 for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
142 usleep_range(1000, 1100);
143 x = dcon_read(dcon, DCON_REG_ID);
146 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
147 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
149 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
152 goto power_up; /* argh, stupid hardware.. */
156 return dcon_hw_init(dcon, 0);
160 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
162 dcon->bl_val = level;
163 dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
165 /* Purposely turn off the backlight when we go to level 0 */
166 if (dcon->bl_val == 0) {
167 dcon->disp_mode &= ~MODE_BL_ENABLE;
168 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
169 } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
170 dcon->disp_mode |= MODE_BL_ENABLE;
171 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
175 /* Set the output type to either color or mono */
176 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
178 if (dcon->mono == enable_mono)
181 dcon->mono = enable_mono;
184 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
185 dcon->disp_mode |= MODE_MONO_LUMA;
187 dcon->disp_mode &= ~(MODE_MONO_LUMA);
188 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
191 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
195 /* For now, this will be really stupid - we need to address how
196 * DCONLOAD works in a sleep and account for it accordingly
199 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
203 /* Turn off the backlight and put the DCON to sleep */
205 if (dcon->asleep == sleep)
208 if (!olpc_board_at_least(olpc_board(0xc2)))
214 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
216 pr_warn("unable to force dcon to power down: %d!\n", x);
218 dcon->asleep = sleep;
220 /* Only re-enable the backlight if the backlight value is set */
221 if (dcon->bl_val != 0)
222 dcon->disp_mode |= MODE_BL_ENABLE;
223 x = dcon_bus_stabilize(dcon, 1);
225 pr_warn("unable to reinit dcon hardware: %d!\n", x);
227 dcon->asleep = sleep;
229 /* Restore backlight */
230 dcon_set_backlight(dcon, dcon->bl_val);
233 /* We should turn off some stuff in the framebuffer - but what? */
236 /* the DCON seems to get confused if we change DCONLOAD too
237 * frequently -- i.e., approximately faster than frame time.
238 * normally we don't change it this fast, so in general we won't
241 static void dcon_load_holdoff(struct dcon_priv *dcon)
243 struct timespec delta_t, now;
246 getnstimeofday(&now);
247 delta_t = timespec_sub(now, dcon->load_time);
248 if (delta_t.tv_sec != 0 ||
249 delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
256 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
261 if (!lock_fb_info(dcon->fbinfo)) {
263 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
267 dcon->ignore_fb_events = true;
268 err = fb_blank(dcon->fbinfo,
269 blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
270 dcon->ignore_fb_events = false;
271 unlock_fb_info(dcon->fbinfo);
275 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
282 /* Set the source of the display (CPU or DCON) */
283 static void dcon_source_switch(struct work_struct *work)
285 struct dcon_priv *dcon = container_of(work, struct dcon_priv,
287 int source = dcon->pending_src;
289 if (dcon->curr_src == source)
292 dcon_load_holdoff(dcon);
294 dcon->switched = false;
297 case DCON_SOURCE_CPU:
298 pr_info("dcon_source_switch to CPU\n");
299 /* Enable the scanline interrupt bit */
300 if (dcon_write(dcon, DCON_REG_MODE,
301 dcon->disp_mode | MODE_SCAN_INT))
302 pr_err("couldn't enable scanline interrupt!\n");
304 /* Wait up to one second for the scanline interrupt */
305 wait_event_timeout(dcon->waitq, dcon->switched, HZ);
308 pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
310 /* Turn off the scanline interrupt */
311 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
312 pr_err("couldn't disable scanline interrupt!\n");
315 * Ideally we'd like to disable interrupts here so that the
316 * fb unblanking and DCON turn on happen at a known time value;
317 * however, we can't do that right now with fb_blank
318 * messing with semaphores.
320 * For now, we just hope..
322 if (!dcon_blank_fb(dcon, false)) {
323 pr_err("Failed to enter CPU mode\n");
324 dcon->pending_src = DCON_SOURCE_DCON;
328 /* And turn off the DCON */
329 pdata->set_dconload(1);
330 getnstimeofday(&dcon->load_time);
332 pr_info("The CPU has control\n");
334 case DCON_SOURCE_DCON:
336 struct timespec delta_t;
338 pr_info("dcon_source_switch to DCON\n");
340 /* Clear DCONLOAD - this implies that the DCON is in control */
341 pdata->set_dconload(0);
342 getnstimeofday(&dcon->load_time);
344 wait_event_timeout(dcon->waitq, dcon->switched, HZ/2);
346 if (!dcon->switched) {
347 pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
349 /* sometimes the DCON doesn't follow its own rules,
350 * and doesn't wait for two vsync pulses before
351 * ack'ing the frame load with an IRQ. the result
352 * is that the display shows the *previously*
353 * loaded frame. we can detect this by looking at
354 * the time between asserting DCONLOAD and the IRQ --
355 * if it's less than 20msec, then the DCON couldn't
356 * have seen two VSYNC pulses. in that case we
357 * deassert and reassert, and hope for the best.
358 * see http://dev.laptop.org/ticket/9664
360 delta_t = timespec_sub(dcon->irq_time, dcon->load_time);
361 if (dcon->switched && delta_t.tv_sec == 0 &&
362 delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
363 pr_err("missed loading, retrying\n");
364 pdata->set_dconload(1);
366 pdata->set_dconload(0);
367 getnstimeofday(&dcon->load_time);
372 dcon_blank_fb(dcon, true);
373 pr_info("The DCON has control\n");
380 dcon->curr_src = source;
383 static void dcon_set_source(struct dcon_priv *dcon, int arg)
385 if (dcon->pending_src == arg)
388 dcon->pending_src = arg;
390 if (dcon->curr_src != arg)
391 schedule_work(&dcon->switch_source);
394 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
396 dcon_set_source(dcon, arg);
397 flush_scheduled_work();
400 static ssize_t dcon_mode_show(struct device *dev,
401 struct device_attribute *attr, char *buf)
403 struct dcon_priv *dcon = dev_get_drvdata(dev);
405 return sprintf(buf, "%4.4X\n", dcon->disp_mode);
408 static ssize_t dcon_sleep_show(struct device *dev,
409 struct device_attribute *attr, char *buf)
411 struct dcon_priv *dcon = dev_get_drvdata(dev);
413 return sprintf(buf, "%d\n", dcon->asleep);
416 static ssize_t dcon_freeze_show(struct device *dev,
417 struct device_attribute *attr, char *buf)
419 struct dcon_priv *dcon = dev_get_drvdata(dev);
421 return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
424 static ssize_t dcon_mono_show(struct device *dev,
425 struct device_attribute *attr, char *buf)
427 struct dcon_priv *dcon = dev_get_drvdata(dev);
429 return sprintf(buf, "%d\n", dcon->mono);
432 static ssize_t dcon_resumeline_show(struct device *dev,
433 struct device_attribute *attr, char *buf)
435 return sprintf(buf, "%d\n", resumeline);
438 static ssize_t dcon_mono_store(struct device *dev,
439 struct device_attribute *attr, const char *buf, size_t count)
441 unsigned long enable_mono;
444 rc = kstrtoul(buf, 10, &enable_mono);
448 dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
453 static ssize_t dcon_freeze_store(struct device *dev,
454 struct device_attribute *attr, const char *buf, size_t count)
456 struct dcon_priv *dcon = dev_get_drvdata(dev);
457 unsigned long output;
460 ret = kstrtoul(buf, 10, &output);
464 pr_info("dcon_freeze_store: %lu\n", output);
468 dcon_set_source(dcon, DCON_SOURCE_CPU);
471 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
473 case 2: /* normally unused */
474 dcon_set_source(dcon, DCON_SOURCE_DCON);
483 static ssize_t dcon_resumeline_store(struct device *dev,
484 struct device_attribute *attr, const char *buf, size_t count)
489 rc = kstrtou16(buf, 10, &rl);
494 dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
499 static ssize_t dcon_sleep_store(struct device *dev,
500 struct device_attribute *attr, const char *buf, size_t count)
502 unsigned long output;
505 ret = kstrtoul(buf, 10, &output);
509 dcon_sleep(dev_get_drvdata(dev), output ? true : false);
513 static struct device_attribute dcon_device_files[] = {
514 __ATTR(mode, 0444, dcon_mode_show, NULL),
515 __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
516 __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
517 __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
518 __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
521 static int dcon_bl_update(struct backlight_device *dev)
523 struct dcon_priv *dcon = bl_get_data(dev);
524 u8 level = dev->props.brightness & 0x0F;
526 if (dev->props.power != FB_BLANK_UNBLANK)
529 if (level != dcon->bl_val)
530 dcon_set_backlight(dcon, level);
532 /* power down the DCON when the screen is blanked */
533 if (!dcon->ignore_fb_events)
534 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
539 static int dcon_bl_get(struct backlight_device *dev)
541 struct dcon_priv *dcon = bl_get_data(dev);
546 static const struct backlight_ops dcon_bl_ops = {
547 .update_status = dcon_bl_update,
548 .get_brightness = dcon_bl_get,
551 static struct backlight_properties dcon_bl_props = {
552 .max_brightness = 15,
553 .type = BACKLIGHT_RAW,
554 .power = FB_BLANK_UNBLANK,
557 static int dcon_reboot_notify(struct notifier_block *nb,
558 unsigned long foo, void *bar)
560 struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
562 if (!dcon || !dcon->client)
565 /* Turn off the DCON. Entirely. */
566 dcon_write(dcon, DCON_REG_MODE, 0x39);
567 dcon_write(dcon, DCON_REG_MODE, 0x32);
571 static int unfreeze_on_panic(struct notifier_block *nb,
572 unsigned long e, void *p)
574 pdata->set_dconload(1);
578 static struct notifier_block dcon_panic_nb = {
579 .notifier_call = unfreeze_on_panic,
582 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
584 strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
589 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
591 struct dcon_priv *dcon;
597 dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
601 dcon->client = client;
602 init_waitqueue_head(&dcon->waitq);
603 INIT_WORK(&dcon->switch_source, dcon_source_switch);
604 dcon->reboot_nb.notifier_call = dcon_reboot_notify;
605 dcon->reboot_nb.priority = -1;
607 i2c_set_clientdata(client, dcon);
609 if (num_registered_fb < 1) {
610 dev_err(&client->dev, "DCON driver requires a registered fb\n");
614 dcon->fbinfo = registered_fb[0];
616 rc = dcon_hw_init(dcon, 1);
620 /* Add the DCON device */
622 dcon_device = platform_device_alloc("dcon", -1);
624 if (dcon_device == NULL) {
625 pr_err("Unable to create the DCON device\n");
629 rc = platform_device_add(dcon_device);
630 platform_set_drvdata(dcon_device, dcon);
633 pr_err("Unable to add the DCON device\n");
637 for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
638 rc = device_create_file(&dcon_device->dev,
639 &dcon_device_files[i]);
641 dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
646 dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
648 /* Add the backlight device for the DCON */
649 dcon_bl_props.brightness = dcon->bl_val;
650 dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
651 dcon, &dcon_bl_ops, &dcon_bl_props);
652 if (IS_ERR(dcon->bl_dev)) {
653 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
654 PTR_ERR(dcon->bl_dev));
658 register_reboot_notifier(&dcon->reboot_nb);
659 atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
664 for (j = 0; j < i; j++)
665 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
667 platform_device_unregister(dcon_device);
670 free_irq(DCON_IRQ, dcon);
676 static int dcon_remove(struct i2c_client *client)
678 struct dcon_priv *dcon = i2c_get_clientdata(client);
680 unregister_reboot_notifier(&dcon->reboot_nb);
681 atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
683 free_irq(DCON_IRQ, dcon);
686 backlight_device_unregister(dcon->bl_dev);
688 if (dcon_device != NULL)
689 platform_device_unregister(dcon_device);
690 cancel_work_sync(&dcon->switch_source);
698 static int dcon_suspend(struct device *dev)
700 struct i2c_client *client = to_i2c_client(dev);
701 struct dcon_priv *dcon = i2c_get_clientdata(client);
704 /* Set up the DCON to have the source */
705 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
711 static int dcon_resume(struct device *dev)
713 struct i2c_client *client = to_i2c_client(dev);
714 struct dcon_priv *dcon = i2c_get_clientdata(client);
717 dcon_bus_stabilize(dcon, 0);
718 dcon_set_source(dcon, DCON_SOURCE_CPU);
726 #define dcon_suspend NULL
727 #define dcon_resume NULL
729 #endif /* CONFIG_PM */
732 irqreturn_t dcon_interrupt(int irq, void *id)
734 struct dcon_priv *dcon = id;
737 if (pdata->read_status(&status))
740 switch (status & 3) {
742 pr_debug("DCONLOAD_MISSED interrupt\n");
745 case 2: /* switch to DCON mode */
746 case 1: /* switch to CPU mode */
747 dcon->switched = true;
748 getnstimeofday(&dcon->irq_time);
749 wake_up(&dcon->waitq);
753 /* workaround resume case: the DCON (on 1.5) doesn't
754 * ever assert status 0x01 when switching to CPU mode
755 * during resume. this is because DCONLOAD is de-asserted
756 * _immediately_ upon exiting S3, so the actual release
757 * of the DCON happened long before this point.
758 * see http://dev.laptop.org/ticket/9869
760 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
761 dcon->switched = true;
762 getnstimeofday(&dcon->irq_time);
763 wake_up(&dcon->waitq);
764 pr_debug("switching w/ status 0/0\n");
766 pr_debug("scanline interrupt w/CPU\n");
773 static const struct dev_pm_ops dcon_pm_ops = {
774 .suspend = dcon_suspend,
775 .resume = dcon_resume,
778 static const struct i2c_device_id dcon_idtable[] = {
782 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
784 struct i2c_driver dcon_driver = {
789 .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
790 .id_table = dcon_idtable,
792 .remove = dcon_remove,
793 .detect = dcon_detect,
794 .address_list = normal_i2c,
797 static int __init olpc_dcon_init(void)
799 #ifdef CONFIG_FB_OLPC_DCON_1_5
801 if (olpc_board_at_least(olpc_board(0xd0)))
802 pdata = &dcon_pdata_xo_1_5;
804 #ifdef CONFIG_FB_OLPC_DCON_1
806 pdata = &dcon_pdata_xo_1;
809 return i2c_add_driver(&dcon_driver);
812 static void __exit olpc_dcon_exit(void)
814 i2c_del_driver(&dcon_driver);
817 module_init(olpc_dcon_init);
818 module_exit(olpc_dcon_exit);
820 MODULE_LICENSE("GPL");