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/pci.h>
21 #include <linux/pci_ids.h>
22 #include <linux/interrupt.h>
23 #include <linux/delay.h>
24 #include <linux/backlight.h>
25 #include <linux/device.h>
26 #include <linux/notifier.h>
27 #include <asm/uaccess.h>
28 #include <linux/ctype.h>
29 #include <linux/reboot.h>
30 #include <linux/gpio.h>
34 #include "olpc_dcon.h"
36 /* Module definitions */
38 static int resumeline = 898;
39 module_param(resumeline, int, 0444);
42 module_param(noinit, int, 0444);
44 /* Default off since it doesn't work on DCON ASIC in B-test OLPC board */
46 module_param(useaa, int, 0444);
48 struct dcon_platform_data {
50 void (*bus_stabilize_wiggle)(void);
51 void (*set_dconload)(int);
52 int (*read_status)(void);
55 static struct dcon_platform_data *pdata;
59 static struct i2c_driver dcon_driver;
60 static struct i2c_client *dcon_client;
62 /* Platform devices */
63 static struct platform_device *dcon_device;
65 /* Backlight device */
66 static struct backlight_device *dcon_bl_dev;
68 static struct fb_info *fbinfo;
70 /* set this to 1 while controlling fb blank state from this driver */
71 static int ignore_fb_events = 0;
73 /* Current source, initialized at probe time */
74 static int dcon_source;
77 static int dcon_pending;
79 /* Current output type */
80 static int dcon_output = DCON_OUTPUT_COLOR;
82 /* Current sleep status (not yet implemented) */
83 static int dcon_sleep_val = DCON_ACTIVE;
85 /* Shadow register for the DCON_REG_MODE register */
86 static unsigned short dcon_disp_mode;
88 /* Variables used during switches */
89 static int dcon_switched;
90 static struct timespec dcon_irq_time;
91 static struct timespec dcon_load_time;
93 static DECLARE_WAIT_QUEUE_HEAD(dcon_wait_queue);
95 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
97 #define dcon_write(reg,val) i2c_smbus_write_word_data(dcon_client,reg,val)
98 #define dcon_read(reg) i2c_smbus_read_word_data(dcon_client,reg)
100 /* The current backlight value - this saves us some smbus traffic */
101 static int bl_val = -1;
103 /* ===== API functions - these are called by a variety of users ==== */
105 static int dcon_hw_init(struct i2c_client *client, int is_init)
110 ver = i2c_smbus_read_word_data(client, DCON_REG_ID);
111 if ((ver >> 8) != 0xDC) {
112 printk(KERN_ERR "olpc-dcon: DCON ID not 0xDCxx: 0x%04x "
119 printk(KERN_INFO "olpc-dcon: Discovered DCON version %x\n",
121 if ((rc = pdata->init()) != 0) {
122 printk(KERN_ERR "olpc-dcon: Unable to init.\n");
127 if (ver < 0xdc02 && !noinit) {
128 /* Initialize the DCON registers */
130 /* Start with work-arounds for DCON ASIC */
131 i2c_smbus_write_word_data(client, 0x4b, 0x00cc);
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, 0x0b, 0x007a);
135 i2c_smbus_write_word_data(client, 0x36, 0x025c);
136 i2c_smbus_write_word_data(client, 0x37, 0x025e);
138 /* Initialise SDRAM */
140 i2c_smbus_write_word_data(client, 0x3b, 0x002b);
141 i2c_smbus_write_word_data(client, 0x41, 0x0101);
142 i2c_smbus_write_word_data(client, 0x42, 0x0101);
145 /* SDRAM setup/hold time */
146 i2c_smbus_write_word_data(client, 0x3a, 0xc040);
147 i2c_smbus_write_word_data(client, 0x41, 0x0000);
148 i2c_smbus_write_word_data(client, 0x41, 0x0101);
149 i2c_smbus_write_word_data(client, 0x42, 0x0101);
152 /* Colour swizzle, AA, no passthrough, backlight */
154 dcon_disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE | MODE_CSWIZZLE;
156 dcon_disp_mode |= MODE_COL_AA;
158 i2c_smbus_write_word_data(client, DCON_REG_MODE, dcon_disp_mode);
161 /* Set the scanline to interrupt on during resume */
162 i2c_smbus_write_word_data(client, DCON_REG_SCAN_INT, resumeline);
169 * The smbus doesn't always come back due to what is believed to be
170 * hardware (power rail) bugs. For older models where this is known to
171 * occur, our solution is to attempt to wait for the bus to stabilize;
172 * if it doesn't happen, cut power to the dcon, repower it, and wait
173 * for the bus to stabilize. Rinse, repeat until we have a working
174 * smbus. For newer models, we simply BUG(); we want to know if this
175 * still happens despite the power fixes that have been made!
177 static int dcon_bus_stabilize(struct i2c_client *client, int is_powered_down)
179 unsigned long timeout;
183 if (is_powered_down) {
185 if ((x = olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0))) {
186 printk(KERN_WARNING "olpc-dcon: unable to force dcon "
187 "to power up: %d!\n", x);
190 msleep(10); /* we'll be conservative */
193 pdata->bus_stabilize_wiggle();
195 for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
197 x = dcon_read(DCON_REG_ID);
200 printk(KERN_ERR "olpc-dcon: unable to stabilize dcon's "
201 "smbus, reasserting power and praying.\n");
202 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
204 olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0);
207 goto power_up; /* argh, stupid hardware.. */
211 return dcon_hw_init(client, 0);
215 static int dcon_get_backlight(void)
217 if (dcon_client == NULL)
221 bl_val = dcon_read(DCON_REG_BRIGHT) & 0x0F;
227 static void dcon_set_backlight_hw(int level)
229 bl_val = level & 0x0F;
230 dcon_write(DCON_REG_BRIGHT, bl_val);
232 /* Purposely turn off the backlight when we go to level 0 */
234 dcon_disp_mode &= ~MODE_BL_ENABLE;
235 dcon_write(DCON_REG_MODE, dcon_disp_mode);
236 } else if (!(dcon_disp_mode & MODE_BL_ENABLE)) {
237 dcon_disp_mode |= MODE_BL_ENABLE;
238 dcon_write(DCON_REG_MODE, dcon_disp_mode);
242 static void dcon_set_backlight(int level)
244 if (dcon_client == NULL)
247 if (bl_val == (level & 0x0F))
250 dcon_set_backlight_hw(level);
253 /* Set the output type to either color or mono */
255 static int dcon_set_output(int arg)
257 if (dcon_output == arg)
262 if (arg == DCON_OUTPUT_MONO) {
263 dcon_disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
264 dcon_disp_mode |= MODE_MONO_LUMA;
267 dcon_disp_mode &= ~(MODE_MONO_LUMA);
268 dcon_disp_mode |= MODE_CSWIZZLE;
270 dcon_disp_mode |= MODE_COL_AA;
273 dcon_write(DCON_REG_MODE, dcon_disp_mode);
277 /* For now, this will be really stupid - we need to address how
278 * DCONLOAD works in a sleep and account for it accordingly
281 static void dcon_sleep(int state)
285 /* Turn off the backlight and put the DCON to sleep */
287 if (state == dcon_sleep_val)
290 if (!olpc_board_at_least(olpc_board(0xc2)))
293 if (state == DCON_SLEEP) {
295 if ((x = olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0)))
296 printk(KERN_WARNING "olpc-dcon: unable to force dcon "
297 "to power down: %d!\n", x);
299 dcon_sleep_val = state;
302 /* Only re-enable the backlight if the backlight value is set */
304 dcon_disp_mode |= MODE_BL_ENABLE;
306 if ((x=dcon_bus_stabilize(dcon_client, 1)))
307 printk(KERN_WARNING "olpc-dcon: unable to reinit dcon"
308 " hardware: %d!\n", x);
310 dcon_sleep_val = state;
312 /* Restore backlight */
313 dcon_set_backlight_hw(bl_val);
316 /* We should turn off some stuff in the framebuffer - but what? */
319 /* the DCON seems to get confused if we change DCONLOAD too
320 * frequently -- i.e., approximately faster than frame time.
321 * normally we don't change it this fast, so in general we won't
324 void dcon_load_holdoff(void)
326 struct timespec delta_t, now;
328 getnstimeofday(&now);
329 delta_t = timespec_sub(now, dcon_load_time);
330 if (delta_t.tv_sec != 0 ||
331 delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
337 /* Set the source of the display (CPU or DCON) */
339 static void dcon_source_switch(struct work_struct *work)
341 DECLARE_WAITQUEUE(wait, current);
342 int source = dcon_pending;
344 if (dcon_source == source)
352 case DCON_SOURCE_CPU:
353 printk("dcon_source_switch to CPU\n");
354 /* Enable the scanline interrupt bit */
355 if (dcon_write(DCON_REG_MODE, dcon_disp_mode | MODE_SCAN_INT))
356 printk(KERN_ERR "olpc-dcon: couldn't enable scanline interrupt!\n");
358 /* Wait up to one second for the scanline interrupt */
359 wait_event_timeout(dcon_wait_queue, dcon_switched == 1, HZ);
363 printk(KERN_ERR "olpc-dcon: Timeout entering CPU mode; expect a screen glitch.\n");
365 /* Turn off the scanline interrupt */
366 if (dcon_write(DCON_REG_MODE, dcon_disp_mode))
367 printk(KERN_ERR "olpc-dcon: couldn't disable scanline interrupt!\n");
370 * Ideally we'd like to disable interrupts here so that the
371 * fb unblanking and DCON turn on happen at a known time value;
372 * however, we can't do that right now with fb_blank
373 * messing with semaphores.
375 * For now, we just hope..
377 acquire_console_sem();
378 ignore_fb_events = 1;
379 if (fb_blank(fbinfo, FB_BLANK_UNBLANK)) {
380 ignore_fb_events = 0;
381 release_console_sem();
382 printk(KERN_ERR "olpc-dcon: Failed to enter CPU mode\n");
383 dcon_pending = DCON_SOURCE_DCON;
386 ignore_fb_events = 0;
387 release_console_sem();
389 /* And turn off the DCON */
390 pdata->set_dconload(1);
391 getnstimeofday(&dcon_load_time);
393 printk(KERN_INFO "olpc-dcon: The CPU has control\n");
395 case DCON_SOURCE_DCON:
398 struct timespec delta_t;
400 printk("dcon_source_switch to DCON\n");
402 add_wait_queue(&dcon_wait_queue, &wait);
403 set_current_state(TASK_UNINTERRUPTIBLE);
405 /* Clear DCONLOAD - this implies that the DCON is in control */
406 pdata->set_dconload(0);
407 getnstimeofday(&dcon_load_time);
409 t = schedule_timeout(HZ/2);
410 remove_wait_queue(&dcon_wait_queue, &wait);
411 set_current_state(TASK_RUNNING);
413 if (!dcon_switched) {
414 printk(KERN_ERR "olpc-dcon: Timeout entering DCON mode; expect a screen glitch.\n");
416 /* sometimes the DCON doesn't follow its own rules,
417 * and doesn't wait for two vsync pulses before
418 * ack'ing the frame load with an IRQ. the result
419 * is that the display shows the *previously*
420 * loaded frame. we can detect this by looking at
421 * the time between asserting DCONLOAD and the IRQ --
422 * if it's less than 20msec, then the DCON couldn't
423 * have seen two VSYNC pulses. in that case we
424 * deassert and reassert, and hope for the best.
425 * see http://dev.laptop.org/ticket/9664
427 delta_t = timespec_sub(dcon_irq_time, dcon_load_time);
428 if (dcon_switched && delta_t.tv_sec == 0 &&
429 delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
430 printk(KERN_ERR "olpc-dcon: missed loading, retrying\n");
431 pdata->set_dconload(1);
433 pdata->set_dconload(0);
434 getnstimeofday(&dcon_load_time);
439 acquire_console_sem();
440 ignore_fb_events = 1;
441 if (fb_blank(fbinfo, FB_BLANK_POWERDOWN))
442 printk(KERN_ERR "olpc-dcon: couldn't blank fb!\n");
443 ignore_fb_events = 0;
444 release_console_sem();
446 printk(KERN_INFO "olpc-dcon: The DCON has control\n");
453 dcon_source = source;
456 static DECLARE_WORK(dcon_work, dcon_source_switch);
458 static void dcon_set_source(int arg)
460 if (dcon_pending == arg)
465 if ((dcon_source != arg) && !work_pending(&dcon_work))
466 schedule_work(&dcon_work);
469 static void dcon_set_source_sync(int arg)
471 dcon_set_source(arg);
472 flush_scheduled_work();
475 static int dconbl_set(struct backlight_device *dev) {
477 int level = dev->props.brightness;
479 if (dev->props.power != FB_BLANK_UNBLANK)
482 dcon_set_backlight(level);
486 static int dconbl_get(struct backlight_device *dev) {
487 return dcon_get_backlight();
490 static ssize_t dcon_mode_show(struct device *dev,
491 struct device_attribute *attr, char *buf)
493 return sprintf(buf, "%4.4X\n", dcon_disp_mode);
496 static ssize_t dcon_sleep_show(struct device *dev,
497 struct device_attribute *attr, char *buf)
500 return sprintf(buf, "%d\n", dcon_sleep_val);
503 static ssize_t dcon_freeze_show(struct device *dev,
504 struct device_attribute *attr, char *buf)
506 return sprintf(buf, "%d\n", dcon_source == DCON_SOURCE_DCON ? 1 : 0);
509 static ssize_t dcon_output_show(struct device *dev,
510 struct device_attribute *attr, char *buf)
512 return sprintf(buf, "%d\n", dcon_output);
515 static ssize_t dcon_resumeline_show(struct device *dev,
516 struct device_attribute *attr, char *buf)
518 return sprintf(buf, "%d\n", resumeline);
521 static int _strtoul(const char *buf, int len, unsigned int *val)
525 unsigned int output = simple_strtoul(buf, &endp, 0);
526 int size = endp - buf;
528 if (*endp && isspace(*endp))
538 static ssize_t dcon_output_store(struct device *dev,
539 struct device_attribute *attr, const char *buf, size_t count)
544 if (_strtoul(buf, count, &output))
547 if (output == DCON_OUTPUT_COLOR || output == DCON_OUTPUT_MONO) {
548 dcon_set_output(output);
555 static ssize_t dcon_freeze_store(struct device *dev,
556 struct device_attribute *attr, const char *buf, size_t count)
560 if (_strtoul(buf, count, &output))
563 printk("dcon_freeze_store: %d\n", output);
567 dcon_set_source(DCON_SOURCE_CPU);
570 dcon_set_source_sync(DCON_SOURCE_DCON);
572 case 2: // normally unused
573 dcon_set_source(DCON_SOURCE_DCON);
582 static ssize_t dcon_resumeline_store(struct device *dev,
583 struct device_attribute *attr, const char *buf, size_t count)
588 if (_strtoul(buf, count, &rl))
592 dcon_write(DCON_REG_SCAN_INT, resumeline);
598 static ssize_t dcon_sleep_store(struct device *dev,
599 struct device_attribute *attr, const char *buf, size_t count)
603 if (_strtoul(buf, count, &output))
606 dcon_sleep(output ? DCON_SLEEP : DCON_ACTIVE);
610 static struct device_attribute dcon_device_files[] = {
611 __ATTR(mode, 0444, dcon_mode_show, NULL),
612 __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
613 __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
614 __ATTR(output, 0644, dcon_output_show, dcon_output_store),
615 __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
618 static struct backlight_ops dcon_bl_ops = {
619 .get_brightness = dconbl_get,
620 .update_status = dconbl_set
624 static int dcon_reboot_notify(struct notifier_block *nb, unsigned long foo, void *bar)
626 if (dcon_client == NULL)
629 /* Turn off the DCON. Entirely. */
630 dcon_write(DCON_REG_MODE, 0x39);
631 dcon_write(DCON_REG_MODE, 0x32);
635 static struct notifier_block dcon_nb = {
636 .notifier_call = dcon_reboot_notify,
640 static int unfreeze_on_panic(struct notifier_block *nb, unsigned long e, void *p)
642 pdata->set_dconload(1);
646 static struct notifier_block dcon_panic_nb = {
647 .notifier_call = unfreeze_on_panic,
651 * When the framebuffer sleeps due to external sources (e.g. user idle), power
652 * down the DCON as well. Power it back up when the fb comes back to life.
654 static int fb_notifier_callback(struct notifier_block *self, unsigned long event, void *data)
656 struct fb_event *evdata = data;
657 int *blank = (int *) evdata->data;
658 if (((event != FB_EVENT_BLANK) && (event != FB_EVENT_CONBLANK)) ||
661 dcon_sleep((*blank) ? DCON_SLEEP : DCON_ACTIVE);
665 static struct notifier_block fb_nb = {
666 .notifier_call = fb_notifier_callback,
669 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
671 strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
676 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
680 if (num_registered_fb >= 1)
681 fbinfo = registered_fb[0];
683 rc = dcon_hw_init(client, 1);
687 /* Add the DCON device */
689 dcon_device = platform_device_alloc("dcon", -1);
691 if (dcon_device == NULL) {
692 printk("dcon: Unable to create the DCON device\n");
697 i2c_set_clientdata(client, dcon_device);
699 if ((rc = platform_device_add(dcon_device))) {
700 printk("dcon: Unable to add the DCON device\n");
704 for(i = 0; i < ARRAY_SIZE(dcon_device_files); i++)
705 device_create_file(&dcon_device->dev, &dcon_device_files[i]);
707 /* Add the backlight device for the DCON */
709 dcon_client = client;
711 dcon_bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
712 NULL, &dcon_bl_ops, NULL);
714 if (IS_ERR(dcon_bl_dev)) {
715 printk("Could not register the backlight device for the DCON (%ld)\n", PTR_ERR(dcon_bl_dev));
719 dcon_bl_dev->props.max_brightness = 15;
720 dcon_bl_dev->props.power = FB_BLANK_UNBLANK;
721 dcon_bl_dev->props.brightness = dcon_get_backlight();
723 backlight_update_status(dcon_bl_dev);
726 register_reboot_notifier(&dcon_nb);
727 atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
728 fb_register_client(&fb_nb);
733 platform_device_unregister(dcon_device);
736 free_irq(DCON_IRQ, &dcon_driver);
741 static int dcon_remove(struct i2c_client *client)
745 fb_unregister_client(&fb_nb);
746 unregister_reboot_notifier(&dcon_nb);
747 atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
749 free_irq(DCON_IRQ, &dcon_driver);
751 if (dcon_bl_dev != NULL)
752 backlight_device_unregister(dcon_bl_dev);
754 if (dcon_device != NULL)
755 platform_device_unregister(dcon_device);
756 cancel_work_sync(&dcon_work);
762 static int dcon_suspend(struct i2c_client *client, pm_message_t state)
764 if (dcon_sleep_val == DCON_ACTIVE) {
765 /* Set up the DCON to have the source */
766 dcon_set_source_sync(DCON_SOURCE_DCON);
772 static int dcon_resume(struct i2c_client *client)
774 if (dcon_sleep_val == DCON_ACTIVE) {
775 dcon_bus_stabilize(client, 0);
776 dcon_set_source(DCON_SOURCE_CPU);
785 static irqreturn_t dcon_interrupt(int irq, void *id)
787 int status = pdata->read_status();
792 switch (status & 3) {
794 printk(KERN_DEBUG "olpc-dcon: DCONLOAD_MISSED interrupt\n");
797 case 2: /* switch to DCON mode */
798 case 1: /* switch to CPU mode */
800 getnstimeofday(&dcon_irq_time);
801 wake_up(&dcon_wait_queue);
805 /* workaround resume case: the DCON (on 1.5) doesn't
806 * ever assert status 0x01 when switching to CPU mode
807 * during resume. this is because DCONLOAD is de-asserted
808 * _immediately_ upon exiting S3, so the actual release
809 * of the DCON happened long before this point.
810 * see http://dev.laptop.org/ticket/9869
812 if (dcon_source != dcon_pending && !dcon_switched) {
814 getnstimeofday(&dcon_irq_time);
815 wake_up(&dcon_wait_queue);
816 printk(KERN_DEBUG "olpc-dcon: switching w/ status 0/0\n");
818 printk(KERN_DEBUG "olpc-dcon: scanline interrupt w/CPU\n");
825 static struct i2c_device_id dcon_idtable[] = {
830 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
832 static struct i2c_driver dcon_driver = {
836 .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
837 .id_table = dcon_idtable,
839 .remove = __devexit_p(dcon_remove),
840 .detect = dcon_detect,
841 .address_list = normal_i2c,
843 .suspend = dcon_suspend,
844 .resume = dcon_resume,
848 #include "olpc_dcon_xo_1.c"
850 static int __init olpc_dcon_init(void)
852 pdata = &dcon_pdata_xo_1;
854 i2c_add_driver(&dcon_driver);
858 static void __exit olpc_dcon_exit(void)
860 i2c_del_driver(&dcon_driver);
863 module_init(olpc_dcon_init);
864 module_exit(olpc_dcon_exit);
866 MODULE_LICENSE("GPL");