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/interrupt.h>
22 #include <linux/delay.h>
23 #include <linux/module.h>
24 #include <linux/backlight.h>
25 #include <linux/device.h>
26 #include <linux/uaccess.h>
27 #include <linux/ctype.h>
28 #include <linux/reboot.h>
29 #include <linux/olpc-ec.h>
33 #include "olpc_dcon.h"
35 /* Module definitions */
37 static ushort resumeline = 898;
38 module_param(resumeline, ushort, 0444);
40 static struct dcon_platform_data *pdata;
44 /* Platform devices */
45 static struct platform_device *dcon_device;
47 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
49 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
51 return i2c_smbus_write_word_data(dcon->client, reg, val);
54 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
56 return i2c_smbus_read_word_data(dcon->client, reg);
59 /* ===== API functions - these are called by a variety of users ==== */
61 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
66 ver = dcon_read(dcon, DCON_REG_ID);
67 if ((ver >> 8) != 0xDC) {
68 pr_err("DCON ID not 0xDCxx: 0x%04x instead.\n", ver);
74 pr_info("Discovered DCON version %x\n", ver & 0xFF);
75 rc = pdata->init(dcon);
77 pr_err("Unable to init.\n");
83 dev_err(&dcon->client->dev,
84 "DCON v1 is unsupported, giving up..\n");
89 /* SDRAM setup/hold time */
90 dcon_write(dcon, 0x3a, 0xc040);
91 dcon_write(dcon, DCON_REG_MEM_OPT_A, 0x0000); /* clear option bits */
92 dcon_write(dcon, DCON_REG_MEM_OPT_A,
93 MEM_DLL_CLOCK_DELAY | MEM_POWER_DOWN);
94 dcon_write(dcon, DCON_REG_MEM_OPT_B, MEM_SOFT_RESET);
96 /* Colour swizzle, AA, no passthrough, backlight */
98 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
99 MODE_CSWIZZLE | MODE_COL_AA;
101 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
104 /* Set the scanline to interrupt on during resume */
105 dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
112 * The smbus doesn't always come back due to what is believed to be
113 * hardware (power rail) bugs. For older models where this is known to
114 * occur, our solution is to attempt to wait for the bus to stabilize;
115 * if it doesn't happen, cut power to the dcon, repower it, and wait
116 * for the bus to stabilize. Rinse, repeat until we have a working
117 * smbus. For newer models, we simply BUG(); we want to know if this
118 * still happens despite the power fixes that have been made!
120 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
122 unsigned long timeout;
127 if (is_powered_down) {
129 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
131 pr_warn("unable to force dcon to power up: %d!\n", x);
134 usleep_range(10000, 11000); /* we'll be conservative */
137 pdata->bus_stabilize_wiggle();
139 for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
140 usleep_range(1000, 1100);
141 x = dcon_read(dcon, DCON_REG_ID);
144 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
145 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
147 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
150 goto power_up; /* argh, stupid hardware.. */
154 return dcon_hw_init(dcon, 0);
158 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
160 dcon->bl_val = level;
161 dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
163 /* Purposely turn off the backlight when we go to level 0 */
164 if (dcon->bl_val == 0) {
165 dcon->disp_mode &= ~MODE_BL_ENABLE;
166 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
167 } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
168 dcon->disp_mode |= MODE_BL_ENABLE;
169 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
173 /* Set the output type to either color or mono */
174 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
176 if (dcon->mono == enable_mono)
179 dcon->mono = enable_mono;
182 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
183 dcon->disp_mode |= MODE_MONO_LUMA;
185 dcon->disp_mode &= ~(MODE_MONO_LUMA);
186 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
189 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
193 /* For now, this will be really stupid - we need to address how
194 * DCONLOAD works in a sleep and account for it accordingly
197 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
201 /* Turn off the backlight and put the DCON to sleep */
203 if (dcon->asleep == sleep)
206 if (!olpc_board_at_least(olpc_board(0xc2)))
212 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
214 pr_warn("unable to force dcon to power down: %d!\n", x);
216 dcon->asleep = sleep;
218 /* Only re-enable the backlight if the backlight value is set */
219 if (dcon->bl_val != 0)
220 dcon->disp_mode |= MODE_BL_ENABLE;
221 x = dcon_bus_stabilize(dcon, 1);
223 pr_warn("unable to reinit dcon hardware: %d!\n", x);
225 dcon->asleep = sleep;
227 /* Restore backlight */
228 dcon_set_backlight(dcon, dcon->bl_val);
231 /* We should turn off some stuff in the framebuffer - but what? */
234 /* the DCON seems to get confused if we change DCONLOAD too
235 * frequently -- i.e., approximately faster than frame time.
236 * normally we don't change it this fast, so in general we won't
239 static void dcon_load_holdoff(struct dcon_priv *dcon)
241 ktime_t delta_t, now;
245 delta_t = ktime_sub(now, dcon->load_time);
246 if (ktime_to_ns(delta_t) > NSEC_PER_MSEC * 20)
252 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
257 if (!lock_fb_info(dcon->fbinfo)) {
259 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
263 dcon->ignore_fb_events = true;
264 err = fb_blank(dcon->fbinfo,
265 blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
266 dcon->ignore_fb_events = false;
267 unlock_fb_info(dcon->fbinfo);
271 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
278 /* Set the source of the display (CPU or DCON) */
279 static void dcon_source_switch(struct work_struct *work)
281 struct dcon_priv *dcon = container_of(work, struct dcon_priv,
283 int source = dcon->pending_src;
285 if (dcon->curr_src == source)
288 dcon_load_holdoff(dcon);
290 dcon->switched = false;
293 case DCON_SOURCE_CPU:
294 pr_info("dcon_source_switch to CPU\n");
295 /* Enable the scanline interrupt bit */
296 if (dcon_write(dcon, DCON_REG_MODE,
297 dcon->disp_mode | MODE_SCAN_INT))
298 pr_err("couldn't enable scanline interrupt!\n");
300 /* Wait up to one second for the scanline interrupt */
301 wait_event_timeout(dcon->waitq, dcon->switched, HZ);
304 pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
306 /* Turn off the scanline interrupt */
307 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
308 pr_err("couldn't disable scanline interrupt!\n");
311 * Ideally we'd like to disable interrupts here so that the
312 * fb unblanking and DCON turn on happen at a known time value;
313 * however, we can't do that right now with fb_blank
314 * messing with semaphores.
316 * For now, we just hope..
318 if (!dcon_blank_fb(dcon, false)) {
319 pr_err("Failed to enter CPU mode\n");
320 dcon->pending_src = DCON_SOURCE_DCON;
324 /* And turn off the DCON */
325 pdata->set_dconload(1);
326 dcon->load_time = ktime_get();
328 pr_info("The CPU has control\n");
330 case DCON_SOURCE_DCON:
334 pr_info("dcon_source_switch to DCON\n");
336 /* Clear DCONLOAD - this implies that the DCON is in control */
337 pdata->set_dconload(0);
338 dcon->load_time = ktime_get();
340 wait_event_timeout(dcon->waitq, dcon->switched, HZ/2);
342 if (!dcon->switched) {
343 pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
345 /* sometimes the DCON doesn't follow its own rules,
346 * and doesn't wait for two vsync pulses before
347 * ack'ing the frame load with an IRQ. the result
348 * is that the display shows the *previously*
349 * loaded frame. we can detect this by looking at
350 * the time between asserting DCONLOAD and the IRQ --
351 * if it's less than 20msec, then the DCON couldn't
352 * have seen two VSYNC pulses. in that case we
353 * deassert and reassert, and hope for the best.
354 * see http://dev.laptop.org/ticket/9664
356 delta_t = ktime_sub(dcon->irq_time, dcon->load_time);
357 if (dcon->switched && ktime_to_ns(delta_t)
358 < NSEC_PER_MSEC * 20) {
359 pr_err("missed loading, retrying\n");
360 pdata->set_dconload(1);
362 pdata->set_dconload(0);
363 dcon->load_time = ktime_get();
368 dcon_blank_fb(dcon, true);
369 pr_info("The DCON has control\n");
376 dcon->curr_src = source;
379 static void dcon_set_source(struct dcon_priv *dcon, int arg)
381 if (dcon->pending_src == arg)
384 dcon->pending_src = arg;
386 if (dcon->curr_src != arg)
387 schedule_work(&dcon->switch_source);
390 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
392 dcon_set_source(dcon, arg);
393 flush_scheduled_work();
396 static ssize_t dcon_mode_show(struct device *dev,
397 struct device_attribute *attr, char *buf)
399 struct dcon_priv *dcon = dev_get_drvdata(dev);
401 return sprintf(buf, "%4.4X\n", dcon->disp_mode);
404 static ssize_t dcon_sleep_show(struct device *dev,
405 struct device_attribute *attr, char *buf)
407 struct dcon_priv *dcon = dev_get_drvdata(dev);
409 return sprintf(buf, "%d\n", dcon->asleep);
412 static ssize_t dcon_freeze_show(struct device *dev,
413 struct device_attribute *attr, char *buf)
415 struct dcon_priv *dcon = dev_get_drvdata(dev);
417 return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
420 static ssize_t dcon_mono_show(struct device *dev,
421 struct device_attribute *attr, char *buf)
423 struct dcon_priv *dcon = dev_get_drvdata(dev);
425 return sprintf(buf, "%d\n", dcon->mono);
428 static ssize_t dcon_resumeline_show(struct device *dev,
429 struct device_attribute *attr, char *buf)
431 return sprintf(buf, "%d\n", resumeline);
434 static ssize_t dcon_mono_store(struct device *dev,
435 struct device_attribute *attr, const char *buf, size_t count)
437 unsigned long enable_mono;
440 rc = kstrtoul(buf, 10, &enable_mono);
444 dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
449 static ssize_t dcon_freeze_store(struct device *dev,
450 struct device_attribute *attr, const char *buf, size_t count)
452 struct dcon_priv *dcon = dev_get_drvdata(dev);
453 unsigned long output;
456 ret = kstrtoul(buf, 10, &output);
460 pr_info("dcon_freeze_store: %lu\n", output);
464 dcon_set_source(dcon, DCON_SOURCE_CPU);
467 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
469 case 2: /* normally unused */
470 dcon_set_source(dcon, DCON_SOURCE_DCON);
479 static ssize_t dcon_resumeline_store(struct device *dev,
480 struct device_attribute *attr, const char *buf, size_t count)
485 rc = kstrtou16(buf, 10, &rl);
490 dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
495 static ssize_t dcon_sleep_store(struct device *dev,
496 struct device_attribute *attr, const char *buf, size_t count)
498 unsigned long output;
501 ret = kstrtoul(buf, 10, &output);
505 dcon_sleep(dev_get_drvdata(dev), output ? true : false);
509 static struct device_attribute dcon_device_files[] = {
510 __ATTR(mode, 0444, dcon_mode_show, NULL),
511 __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
512 __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
513 __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
514 __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
517 static int dcon_bl_update(struct backlight_device *dev)
519 struct dcon_priv *dcon = bl_get_data(dev);
520 u8 level = dev->props.brightness & 0x0F;
522 if (dev->props.power != FB_BLANK_UNBLANK)
525 if (level != dcon->bl_val)
526 dcon_set_backlight(dcon, level);
528 /* power down the DCON when the screen is blanked */
529 if (!dcon->ignore_fb_events)
530 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
535 static int dcon_bl_get(struct backlight_device *dev)
537 struct dcon_priv *dcon = bl_get_data(dev);
542 static const struct backlight_ops dcon_bl_ops = {
543 .update_status = dcon_bl_update,
544 .get_brightness = dcon_bl_get,
547 static struct backlight_properties dcon_bl_props = {
548 .max_brightness = 15,
549 .type = BACKLIGHT_RAW,
550 .power = FB_BLANK_UNBLANK,
553 static int dcon_reboot_notify(struct notifier_block *nb,
554 unsigned long foo, void *bar)
556 struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
558 if (!dcon || !dcon->client)
561 /* Turn off the DCON. Entirely. */
562 dcon_write(dcon, DCON_REG_MODE, 0x39);
563 dcon_write(dcon, DCON_REG_MODE, 0x32);
567 static int unfreeze_on_panic(struct notifier_block *nb,
568 unsigned long e, void *p)
570 pdata->set_dconload(1);
574 static struct notifier_block dcon_panic_nb = {
575 .notifier_call = unfreeze_on_panic,
578 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
580 strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
585 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
587 struct dcon_priv *dcon;
593 dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
597 dcon->client = client;
598 init_waitqueue_head(&dcon->waitq);
599 INIT_WORK(&dcon->switch_source, dcon_source_switch);
600 dcon->reboot_nb.notifier_call = dcon_reboot_notify;
601 dcon->reboot_nb.priority = -1;
603 i2c_set_clientdata(client, dcon);
605 if (num_registered_fb < 1) {
606 dev_err(&client->dev, "DCON driver requires a registered fb\n");
610 dcon->fbinfo = registered_fb[0];
612 rc = dcon_hw_init(dcon, 1);
616 /* Add the DCON device */
618 dcon_device = platform_device_alloc("dcon", -1);
620 if (dcon_device == NULL) {
621 pr_err("Unable to create the DCON device\n");
625 rc = platform_device_add(dcon_device);
626 platform_set_drvdata(dcon_device, dcon);
629 pr_err("Unable to add the DCON device\n");
633 for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
634 rc = device_create_file(&dcon_device->dev,
635 &dcon_device_files[i]);
637 dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
642 dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
644 /* Add the backlight device for the DCON */
645 dcon_bl_props.brightness = dcon->bl_val;
646 dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
647 dcon, &dcon_bl_ops, &dcon_bl_props);
648 if (IS_ERR(dcon->bl_dev)) {
649 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
650 PTR_ERR(dcon->bl_dev));
654 register_reboot_notifier(&dcon->reboot_nb);
655 atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
660 for (j = 0; j < i; j++)
661 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
663 platform_device_unregister(dcon_device);
666 free_irq(DCON_IRQ, dcon);
672 static int dcon_remove(struct i2c_client *client)
674 struct dcon_priv *dcon = i2c_get_clientdata(client);
676 unregister_reboot_notifier(&dcon->reboot_nb);
677 atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
679 free_irq(DCON_IRQ, dcon);
681 backlight_device_unregister(dcon->bl_dev);
683 if (dcon_device != NULL)
684 platform_device_unregister(dcon_device);
685 cancel_work_sync(&dcon->switch_source);
693 static int dcon_suspend(struct device *dev)
695 struct i2c_client *client = to_i2c_client(dev);
696 struct dcon_priv *dcon = i2c_get_clientdata(client);
699 /* Set up the DCON to have the source */
700 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
706 static int dcon_resume(struct device *dev)
708 struct i2c_client *client = to_i2c_client(dev);
709 struct dcon_priv *dcon = i2c_get_clientdata(client);
712 dcon_bus_stabilize(dcon, 0);
713 dcon_set_source(dcon, DCON_SOURCE_CPU);
721 #define dcon_suspend NULL
722 #define dcon_resume NULL
724 #endif /* CONFIG_PM */
727 irqreturn_t dcon_interrupt(int irq, void *id)
729 struct dcon_priv *dcon = id;
732 if (pdata->read_status(&status))
735 switch (status & 3) {
737 pr_debug("DCONLOAD_MISSED interrupt\n");
740 case 2: /* switch to DCON mode */
741 case 1: /* switch to CPU mode */
742 dcon->switched = true;
743 dcon->irq_time = ktime_get();
744 wake_up(&dcon->waitq);
748 /* workaround resume case: the DCON (on 1.5) doesn't
749 * ever assert status 0x01 when switching to CPU mode
750 * during resume. this is because DCONLOAD is de-asserted
751 * _immediately_ upon exiting S3, so the actual release
752 * of the DCON happened long before this point.
753 * see http://dev.laptop.org/ticket/9869
755 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
756 dcon->switched = true;
757 dcon->irq_time = ktime_get();
758 wake_up(&dcon->waitq);
759 pr_debug("switching w/ status 0/0\n");
761 pr_debug("scanline interrupt w/CPU\n");
768 static const struct dev_pm_ops dcon_pm_ops = {
769 .suspend = dcon_suspend,
770 .resume = dcon_resume,
773 static const struct i2c_device_id dcon_idtable[] = {
777 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
779 static struct i2c_driver dcon_driver = {
784 .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
785 .id_table = dcon_idtable,
787 .remove = dcon_remove,
788 .detect = dcon_detect,
789 .address_list = normal_i2c,
792 static int __init olpc_dcon_init(void)
794 #ifdef CONFIG_FB_OLPC_DCON_1_5
796 if (olpc_board_at_least(olpc_board(0xd0)))
797 pdata = &dcon_pdata_xo_1_5;
799 #ifdef CONFIG_FB_OLPC_DCON_1
801 pdata = &dcon_pdata_xo_1;
804 return i2c_add_driver(&dcon_driver);
807 static void __exit olpc_dcon_exit(void)
809 i2c_del_driver(&dcon_driver);
812 module_init(olpc_dcon_init);
813 module_exit(olpc_dcon_exit);
815 MODULE_LICENSE("GPL");