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);
103 /* Set the scanline to interrupt on during resume */
104 dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
111 * The smbus doesn't always come back due to what is believed to be
112 * hardware (power rail) bugs. For older models where this is known to
113 * occur, our solution is to attempt to wait for the bus to stabilize;
114 * if it doesn't happen, cut power to the dcon, repower it, and wait
115 * for the bus to stabilize. Rinse, repeat until we have a working
116 * smbus. For newer models, we simply BUG(); we want to know if this
117 * still happens despite the power fixes that have been made!
119 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
121 unsigned long timeout;
126 if (is_powered_down) {
128 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
130 pr_warn("unable to force dcon to power up: %d!\n", x);
133 usleep_range(10000, 11000); /* we'll be conservative */
136 pdata->bus_stabilize_wiggle();
138 for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
139 usleep_range(1000, 1100);
140 x = dcon_read(dcon, DCON_REG_ID);
143 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
144 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
146 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
149 goto power_up; /* argh, stupid hardware.. */
153 return dcon_hw_init(dcon, 0);
157 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
159 dcon->bl_val = level;
160 dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
162 /* Purposely turn off the backlight when we go to level 0 */
163 if (dcon->bl_val == 0) {
164 dcon->disp_mode &= ~MODE_BL_ENABLE;
165 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
166 } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
167 dcon->disp_mode |= MODE_BL_ENABLE;
168 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
172 /* Set the output type to either color or mono */
173 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
175 if (dcon->mono == enable_mono)
178 dcon->mono = enable_mono;
181 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
182 dcon->disp_mode |= MODE_MONO_LUMA;
184 dcon->disp_mode &= ~(MODE_MONO_LUMA);
185 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
188 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
192 /* For now, this will be really stupid - we need to address how
193 * DCONLOAD works in a sleep and account for it accordingly
196 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
200 /* Turn off the backlight and put the DCON to sleep */
202 if (dcon->asleep == sleep)
205 if (!olpc_board_at_least(olpc_board(0xc2)))
211 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
213 pr_warn("unable to force dcon to power down: %d!\n", x);
215 dcon->asleep = sleep;
217 /* Only re-enable the backlight if the backlight value is set */
218 if (dcon->bl_val != 0)
219 dcon->disp_mode |= MODE_BL_ENABLE;
220 x = dcon_bus_stabilize(dcon, 1);
222 pr_warn("unable to reinit dcon hardware: %d!\n", x);
224 dcon->asleep = sleep;
226 /* Restore backlight */
227 dcon_set_backlight(dcon, dcon->bl_val);
230 /* We should turn off some stuff in the framebuffer - but what? */
233 /* the DCON seems to get confused if we change DCONLOAD too
234 * frequently -- i.e., approximately faster than frame time.
235 * normally we don't change it this fast, so in general we won't
238 static void dcon_load_holdoff(struct dcon_priv *dcon)
240 ktime_t delta_t, now;
244 delta_t = ktime_sub(now, dcon->load_time);
245 if (ktime_to_ns(delta_t) > NSEC_PER_MSEC * 20)
251 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
256 if (!lock_fb_info(dcon->fbinfo)) {
258 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
262 dcon->ignore_fb_events = true;
263 err = fb_blank(dcon->fbinfo,
264 blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
265 dcon->ignore_fb_events = false;
266 unlock_fb_info(dcon->fbinfo);
270 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
277 /* Set the source of the display (CPU or DCON) */
278 static void dcon_source_switch(struct work_struct *work)
280 struct dcon_priv *dcon = container_of(work, struct dcon_priv,
282 int source = dcon->pending_src;
284 if (dcon->curr_src == source)
287 dcon_load_holdoff(dcon);
289 dcon->switched = false;
292 case DCON_SOURCE_CPU:
293 pr_info("%s to CPU\n", __func__);
294 /* Enable the scanline interrupt bit */
295 if (dcon_write(dcon, DCON_REG_MODE,
296 dcon->disp_mode | MODE_SCAN_INT))
297 pr_err("couldn't enable scanline interrupt!\n");
299 /* Wait up to one second for the scanline interrupt */
300 wait_event_timeout(dcon->waitq, dcon->switched, HZ);
303 pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
305 /* Turn off the scanline interrupt */
306 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
307 pr_err("couldn't disable scanline interrupt!\n");
310 * Ideally we'd like to disable interrupts here so that the
311 * fb unblanking and DCON turn on happen at a known time value;
312 * however, we can't do that right now with fb_blank
313 * messing with semaphores.
315 * For now, we just hope..
317 if (!dcon_blank_fb(dcon, false)) {
318 pr_err("Failed to enter CPU mode\n");
319 dcon->pending_src = DCON_SOURCE_DCON;
323 /* And turn off the DCON */
324 pdata->set_dconload(1);
325 dcon->load_time = ktime_get();
327 pr_info("The CPU has control\n");
329 case DCON_SOURCE_DCON:
333 pr_info("%s to DCON\n", __func__);
335 /* Clear DCONLOAD - this implies that the DCON is in control */
336 pdata->set_dconload(0);
337 dcon->load_time = ktime_get();
339 wait_event_timeout(dcon->waitq, dcon->switched, HZ / 2);
341 if (!dcon->switched) {
342 pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
344 /* sometimes the DCON doesn't follow its own rules,
345 * and doesn't wait for two vsync pulses before
346 * ack'ing the frame load with an IRQ. the result
347 * is that the display shows the *previously*
348 * loaded frame. we can detect this by looking at
349 * the time between asserting DCONLOAD and the IRQ --
350 * if it's less than 20msec, then the DCON couldn't
351 * have seen two VSYNC pulses. in that case we
352 * deassert and reassert, and hope for the best.
353 * see http://dev.laptop.org/ticket/9664
355 delta_t = ktime_sub(dcon->irq_time, dcon->load_time);
356 if (dcon->switched && ktime_to_ns(delta_t)
357 < NSEC_PER_MSEC * 20) {
358 pr_err("missed loading, retrying\n");
359 pdata->set_dconload(1);
361 pdata->set_dconload(0);
362 dcon->load_time = ktime_get();
367 dcon_blank_fb(dcon, true);
368 pr_info("The DCON has control\n");
375 dcon->curr_src = source;
378 static void dcon_set_source(struct dcon_priv *dcon, int arg)
380 if (dcon->pending_src == arg)
383 dcon->pending_src = arg;
385 if (dcon->curr_src != arg)
386 schedule_work(&dcon->switch_source);
389 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
391 dcon_set_source(dcon, arg);
392 flush_scheduled_work();
395 static ssize_t dcon_mode_show(struct device *dev,
396 struct device_attribute *attr,
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,
408 struct dcon_priv *dcon = dev_get_drvdata(dev);
410 return sprintf(buf, "%d\n", dcon->asleep);
413 static ssize_t dcon_freeze_show(struct device *dev,
414 struct device_attribute *attr,
417 struct dcon_priv *dcon = dev_get_drvdata(dev);
419 return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
422 static ssize_t dcon_mono_show(struct device *dev,
423 struct device_attribute *attr,
426 struct dcon_priv *dcon = dev_get_drvdata(dev);
428 return sprintf(buf, "%d\n", dcon->mono);
431 static ssize_t dcon_resumeline_show(struct device *dev,
432 struct device_attribute *attr,
435 return sprintf(buf, "%d\n", resumeline);
438 static ssize_t dcon_mono_store(struct device *dev,
439 struct device_attribute *attr,
440 const char *buf, size_t count)
442 unsigned long enable_mono;
445 rc = kstrtoul(buf, 10, &enable_mono);
449 dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
454 static ssize_t dcon_freeze_store(struct device *dev,
455 struct device_attribute *attr,
456 const char *buf, size_t count)
458 struct dcon_priv *dcon = dev_get_drvdata(dev);
459 unsigned long output;
462 ret = kstrtoul(buf, 10, &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,
485 const char *buf, size_t count)
490 rc = kstrtou16(buf, 10, &rl);
495 dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
500 static ssize_t dcon_sleep_store(struct device *dev,
501 struct device_attribute *attr,
502 const char *buf, size_t count)
504 unsigned long output;
507 ret = kstrtoul(buf, 10, &output);
511 dcon_sleep(dev_get_drvdata(dev), output ? true : false);
515 static struct device_attribute dcon_device_files[] = {
516 __ATTR(mode, 0444, dcon_mode_show, NULL),
517 __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
518 __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
519 __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
520 __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
523 static int dcon_bl_update(struct backlight_device *dev)
525 struct dcon_priv *dcon = bl_get_data(dev);
526 u8 level = dev->props.brightness & 0x0F;
528 if (dev->props.power != FB_BLANK_UNBLANK)
531 if (level != dcon->bl_val)
532 dcon_set_backlight(dcon, level);
534 /* power down the DCON when the screen is blanked */
535 if (!dcon->ignore_fb_events)
536 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
541 static int dcon_bl_get(struct backlight_device *dev)
543 struct dcon_priv *dcon = bl_get_data(dev);
548 static const struct backlight_ops dcon_bl_ops = {
549 .update_status = dcon_bl_update,
550 .get_brightness = dcon_bl_get,
553 static struct backlight_properties dcon_bl_props = {
554 .max_brightness = 15,
555 .type = BACKLIGHT_RAW,
556 .power = FB_BLANK_UNBLANK,
559 static int dcon_reboot_notify(struct notifier_block *nb,
560 unsigned long foo, void *bar)
562 struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
564 if (!dcon || !dcon->client)
567 /* Turn off the DCON. Entirely. */
568 dcon_write(dcon, DCON_REG_MODE, 0x39);
569 dcon_write(dcon, DCON_REG_MODE, 0x32);
573 static int unfreeze_on_panic(struct notifier_block *nb,
574 unsigned long e, void *p)
576 pdata->set_dconload(1);
580 static struct notifier_block dcon_panic_nb = {
581 .notifier_call = unfreeze_on_panic,
584 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
586 strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
591 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
593 struct dcon_priv *dcon;
599 dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
603 dcon->client = client;
604 init_waitqueue_head(&dcon->waitq);
605 INIT_WORK(&dcon->switch_source, dcon_source_switch);
606 dcon->reboot_nb.notifier_call = dcon_reboot_notify;
607 dcon->reboot_nb.priority = -1;
609 i2c_set_clientdata(client, dcon);
611 if (num_registered_fb < 1) {
612 dev_err(&client->dev, "DCON driver requires a registered fb\n");
616 dcon->fbinfo = registered_fb[0];
618 rc = dcon_hw_init(dcon, 1);
622 /* Add the DCON device */
624 dcon_device = platform_device_alloc("dcon", -1);
627 pr_err("Unable to create the DCON device\n");
631 rc = platform_device_add(dcon_device);
632 platform_set_drvdata(dcon_device, dcon);
635 pr_err("Unable to add the DCON device\n");
639 for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
640 rc = device_create_file(&dcon_device->dev,
641 &dcon_device_files[i]);
643 dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
648 dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
650 /* Add the backlight device for the DCON */
651 dcon_bl_props.brightness = dcon->bl_val;
652 dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
655 if (IS_ERR(dcon->bl_dev)) {
656 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
657 PTR_ERR(dcon->bl_dev));
661 register_reboot_notifier(&dcon->reboot_nb);
662 atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
667 for (j = 0; j < i; j++)
668 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
670 platform_device_unregister(dcon_device);
673 free_irq(DCON_IRQ, dcon);
679 static int dcon_remove(struct i2c_client *client)
681 struct dcon_priv *dcon = i2c_get_clientdata(client);
683 unregister_reboot_notifier(&dcon->reboot_nb);
684 atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
686 free_irq(DCON_IRQ, dcon);
688 backlight_device_unregister(dcon->bl_dev);
691 platform_device_unregister(dcon_device);
692 cancel_work_sync(&dcon->switch_source);
700 static int dcon_suspend(struct device *dev)
702 struct i2c_client *client = to_i2c_client(dev);
703 struct dcon_priv *dcon = i2c_get_clientdata(client);
706 /* Set up the DCON to have the source */
707 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
713 static int dcon_resume(struct device *dev)
715 struct i2c_client *client = to_i2c_client(dev);
716 struct dcon_priv *dcon = i2c_get_clientdata(client);
719 dcon_bus_stabilize(dcon, 0);
720 dcon_set_source(dcon, DCON_SOURCE_CPU);
728 #define dcon_suspend NULL
729 #define dcon_resume NULL
731 #endif /* CONFIG_PM */
733 irqreturn_t dcon_interrupt(int irq, void *id)
735 struct dcon_priv *dcon = id;
738 if (pdata->read_status(&status))
741 switch (status & 3) {
743 pr_debug("DCONLOAD_MISSED interrupt\n");
746 case 2: /* switch to DCON mode */
747 case 1: /* switch to CPU mode */
748 dcon->switched = true;
749 dcon->irq_time = ktime_get();
750 wake_up(&dcon->waitq);
754 /* workaround resume case: the DCON (on 1.5) doesn't
755 * ever assert status 0x01 when switching to CPU mode
756 * during resume. this is because DCONLOAD is de-asserted
757 * _immediately_ upon exiting S3, so the actual release
758 * of the DCON happened long before this point.
759 * see http://dev.laptop.org/ticket/9869
761 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
762 dcon->switched = true;
763 dcon->irq_time = ktime_get();
764 wake_up(&dcon->waitq);
765 pr_debug("switching w/ status 0/0\n");
767 pr_debug("scanline interrupt w/CPU\n");
774 static const struct dev_pm_ops dcon_pm_ops = {
775 .suspend = dcon_suspend,
776 .resume = dcon_resume,
779 static const struct i2c_device_id dcon_idtable[] = {
783 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
785 static struct i2c_driver dcon_driver = {
790 .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
791 .id_table = dcon_idtable,
793 .remove = dcon_remove,
794 .detect = dcon_detect,
795 .address_list = normal_i2c,
798 static int __init olpc_dcon_init(void)
800 #ifdef CONFIG_FB_OLPC_DCON_1_5
802 if (olpc_board_at_least(olpc_board(0xd0)))
803 pdata = &dcon_pdata_xo_1_5;
805 #ifdef CONFIG_FB_OLPC_DCON_1
807 pdata = &dcon_pdata_xo_1;
810 return i2c_add_driver(&dcon_driver);
813 static void __exit olpc_dcon_exit(void)
815 i2c_del_driver(&dcon_driver);
818 module_init(olpc_dcon_init);
819 module_exit(olpc_dcon_exit);
821 MODULE_LICENSE("GPL");