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 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.
15 #include <linux/kernel.h>
17 #include <linux/console.h>
18 #include <linux/i2c.h>
19 #include <linux/platform_device.h>
20 #include <linux/i2c-id.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/backlight.h>
26 #include <linux/device.h>
27 #include <linux/notifier.h>
28 #include <asm/uaccess.h>
29 #include <linux/ctype.h>
30 #include <linux/reboot.h>
31 #include <linux/gpio.h>
35 #include "olpc_dcon.h"
37 /* Module definitions */
39 static int resumeline = 898;
40 module_param(resumeline, int, 0444);
43 module_param(noinit, int, 0444);
45 /* Default off since it doesn't work on DCON ASIC in B-test OLPC board */
47 module_param(useaa, int, 0444);
49 struct dcon_platform_data {
51 void (*bus_stabilize_wiggle)(void);
52 void (*set_dconload)(int);
53 int (*read_status)(void);
56 static struct dcon_platform_data *pdata;
60 static struct i2c_driver dcon_driver;
61 static struct i2c_client *dcon_client;
63 /* Platform devices */
64 static struct platform_device *dcon_device;
66 /* Backlight device */
67 static struct backlight_device *dcon_bl_dev;
69 static struct fb_info *fbinfo;
71 /* set this to 1 while controlling fb blank state from this driver */
72 static int ignore_fb_events = 0;
74 /* Current source, initialized at probe time */
75 static int dcon_source;
78 static int dcon_pending;
80 /* Current output type */
81 static int dcon_output = DCON_OUTPUT_COLOR;
83 /* Current sleep status (not yet implemented) */
84 static int dcon_sleep_val = DCON_ACTIVE;
86 /* Shadow register for the DCON_REG_MODE register */
87 static unsigned short dcon_disp_mode;
89 /* Variables used during switches */
90 static int dcon_switched;
91 static struct timespec dcon_irq_time;
92 static struct timespec dcon_load_time;
94 static DECLARE_WAIT_QUEUE_HEAD(dcon_wait_queue);
96 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
98 #define dcon_write(reg,val) i2c_smbus_write_word_data(dcon_client,reg,val)
99 #define dcon_read(reg) i2c_smbus_read_word_data(dcon_client,reg)
101 /* The current backlight value - this saves us some smbus traffic */
102 static int bl_val = -1;
104 /* ===== API functions - these are called by a variety of users ==== */
106 static int dcon_hw_init(struct i2c_client *client, int is_init)
111 ver = i2c_smbus_read_word_data(client, DCON_REG_ID);
112 if ((ver >> 8) != 0xDC) {
113 printk(KERN_ERR "olpc-dcon: DCON ID not 0xDCxx: 0x%04x "
120 printk(KERN_INFO "olpc-dcon: Discovered DCON version %x\n",
122 if ((rc = pdata->init()) != 0) {
123 printk(KERN_ERR "olpc-dcon: Unable to init.\n");
128 if (ver < 0xdc02 && !noinit) {
129 /* Initialize the DCON registers */
131 /* Start with work-arounds for DCON ASIC */
132 i2c_smbus_write_word_data(client, 0x4b, 0x00cc);
133 i2c_smbus_write_word_data(client, 0x4b, 0x00cc);
134 i2c_smbus_write_word_data(client, 0x4b, 0x00cc);
135 i2c_smbus_write_word_data(client, 0x0b, 0x007a);
136 i2c_smbus_write_word_data(client, 0x36, 0x025c);
137 i2c_smbus_write_word_data(client, 0x37, 0x025e);
139 /* Initialise SDRAM */
141 i2c_smbus_write_word_data(client, 0x3b, 0x002b);
142 i2c_smbus_write_word_data(client, 0x41, 0x0101);
143 i2c_smbus_write_word_data(client, 0x42, 0x0101);
146 /* SDRAM setup/hold time */
147 i2c_smbus_write_word_data(client, 0x3a, 0xc040);
148 i2c_smbus_write_word_data(client, 0x41, 0x0000);
149 i2c_smbus_write_word_data(client, 0x41, 0x0101);
150 i2c_smbus_write_word_data(client, 0x42, 0x0101);
153 /* Colour swizzle, AA, no passthrough, backlight */
155 dcon_disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE | MODE_CSWIZZLE;
157 dcon_disp_mode |= MODE_COL_AA;
159 i2c_smbus_write_word_data(client, DCON_REG_MODE, dcon_disp_mode);
162 /* Set the scanline to interrupt on during resume */
163 i2c_smbus_write_word_data(client, DCON_REG_SCAN_INT, resumeline);
170 * The smbus doesn't always come back due to what is believed to be
171 * hardware (power rail) bugs. For older models where this is known to
172 * occur, our solution is to attempt to wait for the bus to stabilize;
173 * if it doesn't happen, cut power to the dcon, repower it, and wait
174 * for the bus to stabilize. Rinse, repeat until we have a working
175 * smbus. For newer models, we simply BUG(); we want to know if this
176 * still happens despite the power fixes that have been made!
178 static int dcon_bus_stabilize(struct i2c_client *client, int is_powered_down)
180 unsigned long timeout;
184 if (is_powered_down) {
186 if ((x = olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0))) {
187 printk(KERN_WARNING "olpc-dcon: unable to force dcon "
188 "to power up: %d!\n", x);
191 msleep(10); /* we'll be conservative */
194 pdata->bus_stabilize_wiggle();
196 for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
198 x = dcon_read(DCON_REG_ID);
201 printk(KERN_ERR "olpc-dcon: unable to stabilize dcon's "
202 "smbus, reasserting power and praying.\n");
203 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
205 olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0);
208 goto power_up; /* argh, stupid hardware.. */
212 return dcon_hw_init(client, 0);
216 static int dcon_get_backlight(void)
218 if (dcon_client == NULL)
222 bl_val = dcon_read(DCON_REG_BRIGHT) & 0x0F;
228 static void dcon_set_backlight_hw(int level)
230 bl_val = level & 0x0F;
231 dcon_write(DCON_REG_BRIGHT, bl_val);
233 /* Purposely turn off the backlight when we go to level 0 */
235 dcon_disp_mode &= ~MODE_BL_ENABLE;
236 dcon_write(DCON_REG_MODE, dcon_disp_mode);
237 } else if (!(dcon_disp_mode & MODE_BL_ENABLE)) {
238 dcon_disp_mode |= MODE_BL_ENABLE;
239 dcon_write(DCON_REG_MODE, dcon_disp_mode);
243 static void dcon_set_backlight(int level)
245 if (dcon_client == NULL)
248 if (bl_val == (level & 0x0F))
251 dcon_set_backlight_hw(level);
254 /* Set the output type to either color or mono */
256 static int dcon_set_output(int arg)
258 if (dcon_output == arg)
263 if (arg == DCON_OUTPUT_MONO) {
264 dcon_disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
265 dcon_disp_mode |= MODE_MONO_LUMA;
268 dcon_disp_mode &= ~(MODE_MONO_LUMA);
269 dcon_disp_mode |= MODE_CSWIZZLE;
271 dcon_disp_mode |= MODE_COL_AA;
274 dcon_write(DCON_REG_MODE, dcon_disp_mode);
278 /* For now, this will be really stupid - we need to address how
279 * DCONLOAD works in a sleep and account for it accordingly
282 static void dcon_sleep(int state)
286 /* Turn off the backlight and put the DCON to sleep */
288 if (state == dcon_sleep_val)
291 if (!olpc_board_at_least(olpc_board(0xc2)))
294 if (state == DCON_SLEEP) {
296 if ((x = olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0)))
297 printk(KERN_WARNING "olpc-dcon: unable to force dcon "
298 "to power down: %d!\n", x);
300 dcon_sleep_val = state;
303 /* Only re-enable the backlight if the backlight value is set */
305 dcon_disp_mode |= MODE_BL_ENABLE;
307 if ((x=dcon_bus_stabilize(dcon_client, 1)))
308 printk(KERN_WARNING "olpc-dcon: unable to reinit dcon"
309 " hardware: %d!\n", x);
311 dcon_sleep_val = state;
313 /* Restore backlight */
314 dcon_set_backlight_hw(bl_val);
317 /* We should turn off some stuff in the framebuffer - but what? */
320 /* the DCON seems to get confused if we change DCONLOAD too
321 * frequently -- i.e., approximately faster than frame time.
322 * normally we don't change it this fast, so in general we won't
325 void dcon_load_holdoff(void)
327 struct timespec delta_t, now;
329 getnstimeofday(&now);
330 delta_t = timespec_sub(now, dcon_load_time);
331 if (delta_t.tv_sec != 0 ||
332 delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
338 /* Set the source of the display (CPU or DCON) */
340 static void dcon_source_switch(struct work_struct *work)
342 DECLARE_WAITQUEUE(wait, current);
343 int source = dcon_pending;
345 if (dcon_source == source)
353 case DCON_SOURCE_CPU:
354 printk("dcon_source_switch to CPU\n");
355 /* Enable the scanline interrupt bit */
356 if (dcon_write(DCON_REG_MODE, dcon_disp_mode | MODE_SCAN_INT))
357 printk(KERN_ERR "olpc-dcon: couldn't enable scanline interrupt!\n");
359 /* Wait up to one second for the scanline interrupt */
360 wait_event_timeout(dcon_wait_queue, dcon_switched == 1, HZ);
364 printk(KERN_ERR "olpc-dcon: Timeout entering CPU mode; expect a screen glitch.\n");
366 /* Turn off the scanline interrupt */
367 if (dcon_write(DCON_REG_MODE, dcon_disp_mode))
368 printk(KERN_ERR "olpc-dcon: couldn't disable scanline interrupt!\n");
371 * Ideally we'd like to disable interrupts here so that the
372 * fb unblanking and DCON turn on happen at a known time value;
373 * however, we can't do that right now with fb_blank
374 * messing with semaphores.
376 * For now, we just hope..
378 acquire_console_sem();
379 ignore_fb_events = 1;
380 if (fb_blank(fbinfo, FB_BLANK_UNBLANK)) {
381 ignore_fb_events = 0;
382 release_console_sem();
383 printk(KERN_ERR "olpc-dcon: Failed to enter CPU mode\n");
384 dcon_pending = DCON_SOURCE_DCON;
387 ignore_fb_events = 0;
388 release_console_sem();
390 /* And turn off the DCON */
391 pdata->set_dconload(1);
392 getnstimeofday(&dcon_load_time);
394 printk(KERN_INFO "olpc-dcon: The CPU has control\n");
396 case DCON_SOURCE_DCON:
399 struct timespec delta_t;
401 printk("dcon_source_switch to DCON\n");
403 add_wait_queue(&dcon_wait_queue, &wait);
404 set_current_state(TASK_UNINTERRUPTIBLE);
406 /* Clear DCONLOAD - this implies that the DCON is in control */
407 pdata->set_dconload(0);
408 getnstimeofday(&dcon_load_time);
410 t = schedule_timeout(HZ/2);
411 remove_wait_queue(&dcon_wait_queue, &wait);
412 set_current_state(TASK_RUNNING);
414 if (!dcon_switched) {
415 printk(KERN_ERR "olpc-dcon: Timeout entering DCON mode; expect a screen glitch.\n");
417 /* sometimes the DCON doesn't follow its own rules,
418 * and doesn't wait for two vsync pulses before
419 * ack'ing the frame load with an IRQ. the result
420 * is that the display shows the *previously*
421 * loaded frame. we can detect this by looking at
422 * the time between asserting DCONLOAD and the IRQ --
423 * if it's less than 20msec, then the DCON couldn't
424 * have seen two VSYNC pulses. in that case we
425 * deassert and reassert, and hope for the best.
426 * see http://dev.laptop.org/ticket/9664
428 delta_t = timespec_sub(dcon_irq_time, dcon_load_time);
429 if (dcon_switched && delta_t.tv_sec == 0 &&
430 delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
431 printk(KERN_ERR "olpc-dcon: missed loading, retrying\n");
432 pdata->set_dconload(1);
434 pdata->set_dconload(0);
435 getnstimeofday(&dcon_load_time);
440 acquire_console_sem();
441 ignore_fb_events = 1;
442 if (fb_blank(fbinfo, FB_BLANK_POWERDOWN))
443 printk(KERN_ERR "olpc-dcon: couldn't blank fb!\n");
444 ignore_fb_events = 0;
445 release_console_sem();
447 printk(KERN_INFO "olpc-dcon: The DCON has control\n");
454 dcon_source = source;
457 static DECLARE_WORK(dcon_work, dcon_source_switch);
459 static void dcon_set_source(int arg)
461 if (dcon_pending == arg)
466 if ((dcon_source != arg) && !work_pending(&dcon_work))
467 schedule_work(&dcon_work);
470 static void dcon_set_source_sync(int arg)
472 dcon_set_source(arg);
473 flush_scheduled_work();
476 static int dconbl_set(struct backlight_device *dev) {
478 int level = dev->props.brightness;
480 if (dev->props.power != FB_BLANK_UNBLANK)
483 dcon_set_backlight(level);
487 static int dconbl_get(struct backlight_device *dev) {
488 return dcon_get_backlight();
491 static ssize_t dcon_mode_show(struct device *dev,
492 struct device_attribute *attr, char *buf)
494 return sprintf(buf, "%4.4X\n", dcon_disp_mode);
497 static ssize_t dcon_sleep_show(struct device *dev,
498 struct device_attribute *attr, char *buf)
501 return sprintf(buf, "%d\n", dcon_sleep_val);
504 static ssize_t dcon_freeze_show(struct device *dev,
505 struct device_attribute *attr, char *buf)
507 return sprintf(buf, "%d\n", dcon_source == DCON_SOURCE_DCON ? 1 : 0);
510 static ssize_t dcon_output_show(struct device *dev,
511 struct device_attribute *attr, char *buf)
513 return sprintf(buf, "%d\n", dcon_output);
516 static ssize_t dcon_resumeline_show(struct device *dev,
517 struct device_attribute *attr, char *buf)
519 return sprintf(buf, "%d\n", resumeline);
522 static int _strtoul(const char *buf, int len, unsigned int *val)
526 unsigned int output = simple_strtoul(buf, &endp, 0);
527 int size = endp - buf;
529 if (*endp && isspace(*endp))
539 static ssize_t dcon_output_store(struct device *dev,
540 struct device_attribute *attr, const char *buf, size_t count)
545 if (_strtoul(buf, count, &output))
548 if (output == DCON_OUTPUT_COLOR || output == DCON_OUTPUT_MONO) {
549 dcon_set_output(output);
556 static ssize_t dcon_freeze_store(struct device *dev,
557 struct device_attribute *attr, const char *buf, size_t count)
561 if (_strtoul(buf, count, &output))
564 printk("dcon_freeze_store: %d\n", output);
568 dcon_set_source(DCON_SOURCE_CPU);
571 dcon_set_source_sync(DCON_SOURCE_DCON);
573 case 2: // normally unused
574 dcon_set_source(DCON_SOURCE_DCON);
583 static ssize_t dcon_resumeline_store(struct device *dev,
584 struct device_attribute *attr, const char *buf, size_t count)
589 if (_strtoul(buf, count, &rl))
593 dcon_write(DCON_REG_SCAN_INT, resumeline);
599 static ssize_t dcon_sleep_store(struct device *dev,
600 struct device_attribute *attr, const char *buf, size_t count)
604 if (_strtoul(buf, count, &output))
607 dcon_sleep(output ? DCON_SLEEP : DCON_ACTIVE);
611 static struct device_attribute dcon_device_files[] = {
612 __ATTR(mode, 0444, dcon_mode_show, NULL),
613 __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
614 __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
615 __ATTR(output, 0644, dcon_output_show, dcon_output_store),
616 __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
619 static struct backlight_ops dcon_bl_ops = {
620 .get_brightness = dconbl_get,
621 .update_status = dconbl_set
625 static int dcon_reboot_notify(struct notifier_block *nb, unsigned long foo, void *bar)
627 if (dcon_client == NULL)
630 /* Turn off the DCON. Entirely. */
631 dcon_write(DCON_REG_MODE, 0x39);
632 dcon_write(DCON_REG_MODE, 0x32);
636 static struct notifier_block dcon_nb = {
637 .notifier_call = dcon_reboot_notify,
641 static int unfreeze_on_panic(struct notifier_block *nb, unsigned long e, void *p)
643 pdata->set_dconload(1);
647 static struct notifier_block dcon_panic_nb = {
648 .notifier_call = unfreeze_on_panic,
652 * When the framebuffer sleeps due to external sources (e.g. user idle), power
653 * down the DCON as well. Power it back up when the fb comes back to life.
655 static int fb_notifier_callback(struct notifier_block *self, unsigned long event, void *data)
657 struct fb_event *evdata = data;
658 int *blank = (int *) evdata->data;
659 if (((event != FB_EVENT_BLANK) && (event != FB_EVENT_CONBLANK)) ||
662 dcon_sleep((*blank) ? DCON_SLEEP : DCON_ACTIVE);
666 static struct notifier_block fb_nb = {
667 .notifier_call = fb_notifier_callback,
670 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
672 strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
677 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
681 if (num_registered_fb >= 1)
682 fbinfo = registered_fb[0];
684 rc = dcon_hw_init(client, 1);
688 /* Add the DCON device */
690 dcon_device = platform_device_alloc("dcon", -1);
692 if (dcon_device == NULL) {
693 printk("dcon: Unable to create the DCON device\n");
698 i2c_set_clientdata(client, dcon_device);
700 if ((rc = platform_device_add(dcon_device))) {
701 printk("dcon: Unable to add the DCON device\n");
705 for(i = 0; i < ARRAY_SIZE(dcon_device_files); i++)
706 device_create_file(&dcon_device->dev, &dcon_device_files[i]);
708 /* Add the backlight device for the DCON */
710 dcon_client = client;
712 dcon_bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
713 NULL, &dcon_bl_ops, NULL);
715 if (IS_ERR(dcon_bl_dev)) {
716 printk("Could not register the backlight device for the DCON (%ld)\n", PTR_ERR(dcon_bl_dev));
720 dcon_bl_dev->props.max_brightness = 15;
721 dcon_bl_dev->props.power = FB_BLANK_UNBLANK;
722 dcon_bl_dev->props.brightness = dcon_get_backlight();
724 backlight_update_status(dcon_bl_dev);
727 register_reboot_notifier(&dcon_nb);
728 atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
729 fb_register_client(&fb_nb);
734 platform_device_unregister(dcon_device);
736 i2c_set_clientdata(client, NULL);
738 free_irq(DCON_IRQ, &dcon_driver);
743 static int dcon_remove(struct i2c_client *client)
747 fb_unregister_client(&fb_nb);
748 unregister_reboot_notifier(&dcon_nb);
749 atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
751 free_irq(DCON_IRQ, &dcon_driver);
753 if (dcon_bl_dev != NULL)
754 backlight_device_unregister(dcon_bl_dev);
756 if (dcon_device != NULL)
757 platform_device_unregister(dcon_device);
758 cancel_work_sync(&dcon_work);
760 i2c_set_clientdata(client, NULL);
766 static int dcon_suspend(struct i2c_client *client, pm_message_t state)
768 if (dcon_sleep_val == DCON_ACTIVE) {
769 /* Set up the DCON to have the source */
770 dcon_set_source_sync(DCON_SOURCE_DCON);
776 static int dcon_resume(struct i2c_client *client)
778 if (dcon_sleep_val == DCON_ACTIVE) {
779 dcon_bus_stabilize(client, 0);
780 dcon_set_source(DCON_SOURCE_CPU);
789 static irqreturn_t dcon_interrupt(int irq, void *id)
791 int status = pdata->read_status();
796 switch (status & 3) {
798 printk(KERN_DEBUG "olpc-dcon: DCONLOAD_MISSED interrupt\n");
801 case 2: /* switch to DCON mode */
802 case 1: /* switch to CPU mode */
804 getnstimeofday(&dcon_irq_time);
805 wake_up(&dcon_wait_queue);
809 /* workaround resume case: the DCON (on 1.5) doesn't
810 * ever assert status 0x01 when switching to CPU mode
811 * during resume. this is because DCONLOAD is de-asserted
812 * _immediately_ upon exiting S3, so the actual release
813 * of the DCON happened long before this point.
814 * see http://dev.laptop.org/ticket/9869
816 if (dcon_source != dcon_pending && !dcon_switched) {
818 getnstimeofday(&dcon_irq_time);
819 wake_up(&dcon_wait_queue);
820 printk(KERN_DEBUG "olpc-dcon: switching w/ status 0/0\n");
822 printk(KERN_DEBUG "olpc-dcon: scanline interrupt w/CPU\n");
829 static struct i2c_device_id dcon_idtable[] = {
834 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
836 static struct i2c_driver dcon_driver = {
840 .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
841 .id_table = dcon_idtable,
843 .remove = __devexit_p(dcon_remove),
844 .detect = dcon_detect,
845 .address_list = normal_i2c,
847 .suspend = dcon_suspend,
848 .resume = dcon_resume,
852 #include "olpc_dcon_xo_1.c"
854 static int __init olpc_dcon_init(void)
856 pdata = &dcon_pdata_xo_1;
858 i2c_add_driver(&dcon_driver);
862 static void __exit olpc_dcon_exit(void)
864 i2c_del_driver(&dcon_driver);
867 module_init(olpc_dcon_init);
868 module_exit(olpc_dcon_exit);
870 MODULE_LICENSE("GPL");