Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

Linux/drivers/staging/olpc_dcon/olpc_dcon.c

  1 /*
  2  * Mainly by David Woodhouse, somewhat modified by Jordan Crouse
  3  *
  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>
  8  *
  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.
 12  */
 13 
 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 15 
 16 #include <linux/kernel.h>
 17 #include <linux/fb.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>
 32 #include <asm/tsc.h>
 33 #include <asm/olpc.h>
 34 
 35 #include "olpc_dcon.h"
 36 
 37 /* Module definitions */
 38 
 39 static ushort resumeline = 898;
 40 module_param(resumeline, ushort, 0444);
 41 
 42 static struct dcon_platform_data *pdata;
 43 
 44 /* I2C structures */
 45 
 46 /* Platform devices */
 47 static struct platform_device *dcon_device;
 48 
 49 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
 50 
 51 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
 52 {
 53         return i2c_smbus_write_word_data(dcon->client, reg, val);
 54 }
 55 
 56 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
 57 {
 58         return i2c_smbus_read_word_data(dcon->client, reg);
 59 }
 60 
 61 /* ===== API functions - these are called by a variety of users ==== */
 62 
 63 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
 64 {
 65         uint16_t ver;
 66         int rc = 0;
 67 
 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);
 71                 rc = -ENXIO;
 72                 goto err;
 73         }
 74 
 75         if (is_init) {
 76                 pr_info("Discovered DCON version %x\n", ver & 0xFF);
 77                 rc = pdata->init(dcon);
 78                 if (rc != 0) {
 79                         pr_err("Unable to init.\n");
 80                         goto err;
 81                 }
 82         }
 83 
 84         if (ver < 0xdc02) {
 85                 dev_err(&dcon->client->dev,
 86                                 "DCON v1 is unsupported, giving up..\n");
 87                 rc = -ENODEV;
 88                 goto err;
 89         }
 90 
 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);
 97 
 98         /* Colour swizzle, AA, no passthrough, backlight */
 99         if (is_init) {
100                 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
101                                 MODE_CSWIZZLE | MODE_COL_AA;
102         }
103         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
104 
105 
106         /* Set the scanline to interrupt on during resume */
107         dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
108 
109 err:
110         return rc;
111 }
112 
113 /*
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!
121  */
122 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
123 {
124         unsigned long timeout;
125         u8 pm;
126         int x;
127 
128 power_up:
129         if (is_powered_down) {
130                 pm = 1;
131                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
132                 if (x) {
133                         pr_warn("unable to force dcon to power up: %d!\n", x);
134                         return x;
135                 }
136                 usleep_range(10000, 11000);  /* we'll be conservative */
137         }
138 
139         pdata->bus_stabilize_wiggle();
140 
141         for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
142                 usleep_range(1000, 1100);
143                 x = dcon_read(dcon, DCON_REG_ID);
144         }
145         if (x < 0) {
146                 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
147                 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
148                 pm = 0;
149                 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
150                 msleep(100);
151                 is_powered_down = 1;
152                 goto power_up;  /* argh, stupid hardware.. */
153         }
154 
155         if (is_powered_down)
156                 return dcon_hw_init(dcon, 0);
157         return 0;
158 }
159 
160 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
161 {
162         dcon->bl_val = level;
163         dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
164 
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);
172         }
173 }
174 
175 /* Set the output type to either color or mono */
176 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
177 {
178         if (dcon->mono == enable_mono)
179                 return 0;
180 
181         dcon->mono = enable_mono;
182 
183         if (enable_mono) {
184                 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
185                 dcon->disp_mode |= MODE_MONO_LUMA;
186         } else {
187                 dcon->disp_mode &= ~(MODE_MONO_LUMA);
188                 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
189         }
190 
191         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
192         return 0;
193 }
194 
195 /* For now, this will be really stupid - we need to address how
196  * DCONLOAD works in a sleep and account for it accordingly
197  */
198 
199 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
200 {
201         int x;
202 
203         /* Turn off the backlight and put the DCON to sleep */
204 
205         if (dcon->asleep == sleep)
206                 return;
207 
208         if (!olpc_board_at_least(olpc_board(0xc2)))
209                 return;
210 
211         if (sleep) {
212                 u8 pm = 0;
213                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
214                 if (x)
215                         pr_warn("unable to force dcon to power down: %d!\n", x);
216                 else
217                         dcon->asleep = sleep;
218         } else {
219                 /* Only re-enable the backlight if the backlight value is set */
220                 if (dcon->bl_val != 0)
221                         dcon->disp_mode |= MODE_BL_ENABLE;
222                 x = dcon_bus_stabilize(dcon, 1);
223                 if (x)
224                         pr_warn("unable to reinit dcon hardware: %d!\n", x);
225                 else
226                         dcon->asleep = sleep;
227 
228                 /* Restore backlight */
229                 dcon_set_backlight(dcon, dcon->bl_val);
230         }
231 
232         /* We should turn off some stuff in the framebuffer - but what? */
233 }
234 
235 /* the DCON seems to get confused if we change DCONLOAD too
236  * frequently -- i.e., approximately faster than frame time.
237  * normally we don't change it this fast, so in general we won't
238  * delay here.
239  */
240 static void dcon_load_holdoff(struct dcon_priv *dcon)
241 {
242         struct timespec delta_t, now;
243         while (1) {
244                 getnstimeofday(&now);
245                 delta_t = timespec_sub(now, dcon->load_time);
246                 if (delta_t.tv_sec != 0 ||
247                         delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
248                         break;
249                 }
250                 mdelay(4);
251         }
252 }
253 
254 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
255 {
256         int err;
257 
258         console_lock();
259         if (!lock_fb_info(dcon->fbinfo)) {
260                 console_unlock();
261                 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
262                 return false;
263         }
264 
265         dcon->ignore_fb_events = true;
266         err = fb_blank(dcon->fbinfo,
267                         blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
268         dcon->ignore_fb_events = false;
269         unlock_fb_info(dcon->fbinfo);
270         console_unlock();
271 
272         if (err) {
273                 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
274                                 blank ? "" : "un");
275                 return false;
276         }
277         return true;
278 }
279 
280 /* Set the source of the display (CPU or DCON) */
281 static void dcon_source_switch(struct work_struct *work)
282 {
283         struct dcon_priv *dcon = container_of(work, struct dcon_priv,
284                         switch_source);
285         int source = dcon->pending_src;
286 
287         if (dcon->curr_src == source)
288                 return;
289 
290         dcon_load_holdoff(dcon);
291 
292         dcon->switched = false;
293 
294         switch (source) {
295         case DCON_SOURCE_CPU:
296                 pr_info("dcon_source_switch to CPU\n");
297                 /* Enable the scanline interrupt bit */
298                 if (dcon_write(dcon, DCON_REG_MODE,
299                                 dcon->disp_mode | MODE_SCAN_INT))
300                         pr_err("couldn't enable scanline interrupt!\n");
301                 else
302                         /* Wait up to one second for the scanline interrupt */
303                         wait_event_timeout(dcon->waitq, dcon->switched, HZ);
304 
305                 if (!dcon->switched)
306                         pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
307 
308                 /* Turn off the scanline interrupt */
309                 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
310                         pr_err("couldn't disable scanline interrupt!\n");
311 
312                 /*
313                  * Ideally we'd like to disable interrupts here so that the
314                  * fb unblanking and DCON turn on happen at a known time value;
315                  * however, we can't do that right now with fb_blank
316                  * messing with semaphores.
317                  *
318                  * For now, we just hope..
319                  */
320                 if (!dcon_blank_fb(dcon, false)) {
321                         pr_err("Failed to enter CPU mode\n");
322                         dcon->pending_src = DCON_SOURCE_DCON;
323                         return;
324                 }
325 
326                 /* And turn off the DCON */
327                 pdata->set_dconload(1);
328                 getnstimeofday(&dcon->load_time);
329 
330                 pr_info("The CPU has control\n");
331                 break;
332         case DCON_SOURCE_DCON:
333         {
334                 struct timespec delta_t;
335 
336                 pr_info("dcon_source_switch to DCON\n");
337 
338                 /* Clear DCONLOAD - this implies that the DCON is in control */
339                 pdata->set_dconload(0);
340                 getnstimeofday(&dcon->load_time);
341 
342                 wait_event_timeout(dcon->waitq, dcon->switched, HZ/2);
343 
344                 if (!dcon->switched) {
345                         pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
346                 } else {
347                         /* sometimes the DCON doesn't follow its own rules,
348                          * and doesn't wait for two vsync pulses before
349                          * ack'ing the frame load with an IRQ.  the result
350                          * is that the display shows the *previously*
351                          * loaded frame.  we can detect this by looking at
352                          * the time between asserting DCONLOAD and the IRQ --
353                          * if it's less than 20msec, then the DCON couldn't
354                          * have seen two VSYNC pulses.  in that case we
355                          * deassert and reassert, and hope for the best.
356                          * see http://dev.laptop.org/ticket/9664
357                          */
358                         delta_t = timespec_sub(dcon->irq_time, dcon->load_time);
359                         if (dcon->switched && delta_t.tv_sec == 0 &&
360                                         delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
361                                 pr_err("missed loading, retrying\n");
362                                 pdata->set_dconload(1);
363                                 mdelay(41);
364                                 pdata->set_dconload(0);
365                                 getnstimeofday(&dcon->load_time);
366                                 mdelay(41);
367                         }
368                 }
369 
370                 dcon_blank_fb(dcon, true);
371                 pr_info("The DCON has control\n");
372                 break;
373         }
374         default:
375                 BUG();
376         }
377 
378         dcon->curr_src = source;
379 }
380 
381 static void dcon_set_source(struct dcon_priv *dcon, int arg)
382 {
383         if (dcon->pending_src == arg)
384                 return;
385 
386         dcon->pending_src = arg;
387 
388         if (dcon->curr_src != arg)
389                 schedule_work(&dcon->switch_source);
390 }
391 
392 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
393 {
394         dcon_set_source(dcon, arg);
395         flush_scheduled_work();
396 }
397 
398 static ssize_t dcon_mode_show(struct device *dev,
399         struct device_attribute *attr, char *buf)
400 {
401         struct dcon_priv *dcon = dev_get_drvdata(dev);
402         return sprintf(buf, "%4.4X\n", dcon->disp_mode);
403 }
404 
405 static ssize_t dcon_sleep_show(struct device *dev,
406         struct device_attribute *attr, char *buf)
407 {
408 
409         struct dcon_priv *dcon = dev_get_drvdata(dev);
410         return sprintf(buf, "%d\n", dcon->asleep);
411 }
412 
413 static ssize_t dcon_freeze_show(struct device *dev,
414         struct device_attribute *attr, char *buf)
415 {
416         struct dcon_priv *dcon = dev_get_drvdata(dev);
417         return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
418 }
419 
420 static ssize_t dcon_mono_show(struct device *dev,
421         struct device_attribute *attr, char *buf)
422 {
423         struct dcon_priv *dcon = dev_get_drvdata(dev);
424         return sprintf(buf, "%d\n", dcon->mono);
425 }
426 
427 static ssize_t dcon_resumeline_show(struct device *dev,
428         struct device_attribute *attr, char *buf)
429 {
430         return sprintf(buf, "%d\n", resumeline);
431 }
432 
433 static ssize_t dcon_mono_store(struct device *dev,
434         struct device_attribute *attr, const char *buf, size_t count)
435 {
436         unsigned long enable_mono;
437         int rc;
438 
439         rc = kstrtoul(buf, 10, &enable_mono);
440         if (rc)
441                 return rc;
442 
443         dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
444 
445         return count;
446 }
447 
448 static ssize_t dcon_freeze_store(struct device *dev,
449         struct device_attribute *attr, const char *buf, size_t count)
450 {
451         struct dcon_priv *dcon = dev_get_drvdata(dev);
452         unsigned long output;
453         int ret;
454 
455         ret = kstrtoul(buf, 10, &output);
456         if (ret)
457                 return ret;
458 
459         pr_info("dcon_freeze_store: %lu\n", output);
460 
461         switch (output) {
462         case 0:
463                 dcon_set_source(dcon, DCON_SOURCE_CPU);
464                 break;
465         case 1:
466                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
467                 break;
468         case 2:  /* normally unused */
469                 dcon_set_source(dcon, DCON_SOURCE_DCON);
470                 break;
471         default:
472                 return -EINVAL;
473         }
474 
475         return count;
476 }
477 
478 static ssize_t dcon_resumeline_store(struct device *dev,
479         struct device_attribute *attr, const char *buf, size_t count)
480 {
481         unsigned short rl;
482         int rc;
483 
484         rc = kstrtou16(buf, 10, &rl);
485         if (rc)
486                 return rc;
487 
488         resumeline = rl;
489         dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
490 
491         return count;
492 }
493 
494 static ssize_t dcon_sleep_store(struct device *dev,
495         struct device_attribute *attr, const char *buf, size_t count)
496 {
497         unsigned long output;
498         int ret;
499 
500         ret = kstrtoul(buf, 10, &output);
501         if (ret)
502                 return ret;
503 
504         dcon_sleep(dev_get_drvdata(dev), output ? true : false);
505         return count;
506 }
507 
508 static struct device_attribute dcon_device_files[] = {
509         __ATTR(mode, 0444, dcon_mode_show, NULL),
510         __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
511         __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
512         __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
513         __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
514 };
515 
516 static int dcon_bl_update(struct backlight_device *dev)
517 {
518         struct dcon_priv *dcon = bl_get_data(dev);
519         u8 level = dev->props.brightness & 0x0F;
520 
521         if (dev->props.power != FB_BLANK_UNBLANK)
522                 level = 0;
523 
524         if (level != dcon->bl_val)
525                 dcon_set_backlight(dcon, level);
526 
527         /* power down the DCON when the screen is blanked */
528         if (!dcon->ignore_fb_events)
529                 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
530 
531         return 0;
532 }
533 
534 static int dcon_bl_get(struct backlight_device *dev)
535 {
536         struct dcon_priv *dcon = bl_get_data(dev);
537         return dcon->bl_val;
538 }
539 
540 static const struct backlight_ops dcon_bl_ops = {
541         .update_status = dcon_bl_update,
542         .get_brightness = dcon_bl_get,
543 };
544 
545 static struct backlight_properties dcon_bl_props = {
546         .max_brightness = 15,
547         .type = BACKLIGHT_RAW,
548         .power = FB_BLANK_UNBLANK,
549 };
550 
551 static int dcon_reboot_notify(struct notifier_block *nb,
552                               unsigned long foo, void *bar)
553 {
554         struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
555 
556         if (!dcon || !dcon->client)
557                 return NOTIFY_DONE;
558 
559         /* Turn off the DCON. Entirely. */
560         dcon_write(dcon, DCON_REG_MODE, 0x39);
561         dcon_write(dcon, DCON_REG_MODE, 0x32);
562         return NOTIFY_DONE;
563 }
564 
565 static int unfreeze_on_panic(struct notifier_block *nb,
566                              unsigned long e, void *p)
567 {
568         pdata->set_dconload(1);
569         return NOTIFY_DONE;
570 }
571 
572 static struct notifier_block dcon_panic_nb = {
573         .notifier_call = unfreeze_on_panic,
574 };
575 
576 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
577 {
578         strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
579 
580         return 0;
581 }
582 
583 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
584 {
585         struct dcon_priv *dcon;
586         int rc, i, j;
587 
588         if (!pdata)
589                 return -ENXIO;
590 
591         dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
592         if (!dcon)
593                 return -ENOMEM;
594 
595         dcon->client = client;
596         init_waitqueue_head(&dcon->waitq);
597         INIT_WORK(&dcon->switch_source, dcon_source_switch);
598         dcon->reboot_nb.notifier_call = dcon_reboot_notify;
599         dcon->reboot_nb.priority = -1;
600 
601         i2c_set_clientdata(client, dcon);
602 
603         if (num_registered_fb < 1) {
604                 dev_err(&client->dev, "DCON driver requires a registered fb\n");
605                 rc = -EIO;
606                 goto einit;
607         }
608         dcon->fbinfo = registered_fb[0];
609 
610         rc = dcon_hw_init(dcon, 1);
611         if (rc)
612                 goto einit;
613 
614         /* Add the DCON device */
615 
616         dcon_device = platform_device_alloc("dcon", -1);
617 
618         if (dcon_device == NULL) {
619                 pr_err("Unable to create the DCON device\n");
620                 rc = -ENOMEM;
621                 goto eirq;
622         }
623         rc = platform_device_add(dcon_device);
624         platform_set_drvdata(dcon_device, dcon);
625 
626         if (rc) {
627                 pr_err("Unable to add the DCON device\n");
628                 goto edev;
629         }
630 
631         for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
632                 rc = device_create_file(&dcon_device->dev,
633                                         &dcon_device_files[i]);
634                 if (rc) {
635                         dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
636                         goto ecreate;
637                 }
638         }
639 
640         dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
641 
642         /* Add the backlight device for the DCON */
643         dcon_bl_props.brightness = dcon->bl_val;
644         dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
645                 dcon, &dcon_bl_ops, &dcon_bl_props);
646         if (IS_ERR(dcon->bl_dev)) {
647                 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
648                                 PTR_ERR(dcon->bl_dev));
649                 dcon->bl_dev = NULL;
650         }
651 
652         register_reboot_notifier(&dcon->reboot_nb);
653         atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
654 
655         return 0;
656 
657  ecreate:
658         for (j = 0; j < i; j++)
659                 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
660  edev:
661         platform_device_unregister(dcon_device);
662         dcon_device = NULL;
663  eirq:
664         free_irq(DCON_IRQ, dcon);
665  einit:
666         kfree(dcon);
667         return rc;
668 }
669 
670 static int dcon_remove(struct i2c_client *client)
671 {
672         struct dcon_priv *dcon = i2c_get_clientdata(client);
673 
674         unregister_reboot_notifier(&dcon->reboot_nb);
675         atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
676 
677         free_irq(DCON_IRQ, dcon);
678 
679         if (dcon->bl_dev)
680                 backlight_device_unregister(dcon->bl_dev);
681 
682         if (dcon_device != NULL)
683                 platform_device_unregister(dcon_device);
684         cancel_work_sync(&dcon->switch_source);
685 
686         kfree(dcon);
687 
688         return 0;
689 }
690 
691 #ifdef CONFIG_PM
692 static int dcon_suspend(struct device *dev)
693 {
694         struct i2c_client *client = to_i2c_client(dev);
695         struct dcon_priv *dcon = i2c_get_clientdata(client);
696 
697         if (!dcon->asleep) {
698                 /* Set up the DCON to have the source */
699                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
700         }
701 
702         return 0;
703 }
704 
705 static int dcon_resume(struct device *dev)
706 {
707         struct i2c_client *client = to_i2c_client(dev);
708         struct dcon_priv *dcon = i2c_get_clientdata(client);
709 
710         if (!dcon->asleep) {
711                 dcon_bus_stabilize(dcon, 0);
712                 dcon_set_source(dcon, DCON_SOURCE_CPU);
713         }
714 
715         return 0;
716 }
717 
718 #else
719 
720 #define dcon_suspend NULL
721 #define dcon_resume NULL
722 
723 #endif /* CONFIG_PM */
724 
725 
726 irqreturn_t dcon_interrupt(int irq, void *id)
727 {
728         struct dcon_priv *dcon = id;
729         u8 status;
730 
731         if (pdata->read_status(&status))
732                 return IRQ_NONE;
733 
734         switch (status & 3) {
735         case 3:
736                 pr_debug("DCONLOAD_MISSED interrupt\n");
737                 break;
738 
739         case 2: /* switch to DCON mode */
740         case 1: /* switch to CPU mode */
741                 dcon->switched = true;
742                 getnstimeofday(&dcon->irq_time);
743                 wake_up(&dcon->waitq);
744                 break;
745 
746         case 0:
747                 /* workaround resume case:  the DCON (on 1.5) doesn't
748                  * ever assert status 0x01 when switching to CPU mode
749                  * during resume.  this is because DCONLOAD is de-asserted
750                  * _immediately_ upon exiting S3, so the actual release
751                  * of the DCON happened long before this point.
752                  * see http://dev.laptop.org/ticket/9869
753                  */
754                 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
755                         dcon->switched = true;
756                         getnstimeofday(&dcon->irq_time);
757                         wake_up(&dcon->waitq);
758                         pr_debug("switching w/ status 0/0\n");
759                 } else {
760                         pr_debug("scanline interrupt w/CPU\n");
761                 }
762         }
763 
764         return IRQ_HANDLED;
765 }
766 
767 static const struct dev_pm_ops dcon_pm_ops = {
768         .suspend = dcon_suspend,
769         .resume = dcon_resume,
770 };
771 
772 static const struct i2c_device_id dcon_idtable[] = {
773         { "olpc_dcon",  0 },
774         { }
775 };
776 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
777 
778 struct i2c_driver dcon_driver = {
779         .driver = {
780                 .name   = "olpc_dcon",
781                 .pm = &dcon_pm_ops,
782         },
783         .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
784         .id_table = dcon_idtable,
785         .probe = dcon_probe,
786         .remove = dcon_remove,
787         .detect = dcon_detect,
788         .address_list = normal_i2c,
789 };
790 
791 static int __init olpc_dcon_init(void)
792 {
793 #ifdef CONFIG_FB_OLPC_DCON_1_5
794         /* XO-1.5 */
795         if (olpc_board_at_least(olpc_board(0xd0)))
796                 pdata = &dcon_pdata_xo_1_5;
797 #endif
798 #ifdef CONFIG_FB_OLPC_DCON_1
799         if (!pdata)
800                 pdata = &dcon_pdata_xo_1;
801 #endif
802 
803         return i2c_add_driver(&dcon_driver);
804 }
805 
806 static void __exit olpc_dcon_exit(void)
807 {
808         i2c_del_driver(&dcon_driver);
809 }
810 
811 module_init(olpc_dcon_init);
812 module_exit(olpc_dcon_exit);
813 
814 MODULE_LICENSE("GPL");
815 

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