Version:  2.0.40 2.2.26 2.4.37 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1

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/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>
 30 #include <asm/tsc.h>
 31 #include <asm/olpc.h>
 32 
 33 #include "olpc_dcon.h"
 34 
 35 /* Module definitions */
 36 
 37 static ushort resumeline = 898;
 38 module_param(resumeline, ushort, 0444);
 39 
 40 static struct dcon_platform_data *pdata;
 41 
 42 /* I2C structures */
 43 
 44 /* Platform devices */
 45 static struct platform_device *dcon_device;
 46 
 47 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
 48 
 49 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
 50 {
 51         return i2c_smbus_write_word_data(dcon->client, reg, val);
 52 }
 53 
 54 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
 55 {
 56         return i2c_smbus_read_word_data(dcon->client, reg);
 57 }
 58 
 59 /* ===== API functions - these are called by a variety of users ==== */
 60 
 61 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
 62 {
 63         uint16_t ver;
 64         int rc = 0;
 65 
 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);
 69                 rc = -ENXIO;
 70                 goto err;
 71         }
 72 
 73         if (is_init) {
 74                 pr_info("Discovered DCON version %x\n", ver & 0xFF);
 75                 rc = pdata->init(dcon);
 76                 if (rc != 0) {
 77                         pr_err("Unable to init.\n");
 78                         goto err;
 79                 }
 80         }
 81 
 82         if (ver < 0xdc02) {
 83                 dev_err(&dcon->client->dev,
 84                                 "DCON v1 is unsupported, giving up..\n");
 85                 rc = -ENODEV;
 86                 goto err;
 87         }
 88 
 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);
 95 
 96         /* Colour swizzle, AA, no passthrough, backlight */
 97         if (is_init) {
 98                 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
 99                                 MODE_CSWIZZLE | MODE_COL_AA;
100         }
101         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
102 
103 
104         /* Set the scanline to interrupt on during resume */
105         dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
106 
107 err:
108         return rc;
109 }
110 
111 /*
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!
119  */
120 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
121 {
122         unsigned long timeout;
123         u8 pm;
124         int x;
125 
126 power_up:
127         if (is_powered_down) {
128                 pm = 1;
129                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
130                 if (x) {
131                         pr_warn("unable to force dcon to power up: %d!\n", x);
132                         return x;
133                 }
134                 usleep_range(10000, 11000);  /* we'll be conservative */
135         }
136 
137         pdata->bus_stabilize_wiggle();
138 
139         for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
140                 usleep_range(1000, 1100);
141                 x = dcon_read(dcon, DCON_REG_ID);
142         }
143         if (x < 0) {
144                 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
145                 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
146                 pm = 0;
147                 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
148                 msleep(100);
149                 is_powered_down = 1;
150                 goto power_up;  /* argh, stupid hardware.. */
151         }
152 
153         if (is_powered_down)
154                 return dcon_hw_init(dcon, 0);
155         return 0;
156 }
157 
158 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
159 {
160         dcon->bl_val = level;
161         dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
162 
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);
170         }
171 }
172 
173 /* Set the output type to either color or mono */
174 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
175 {
176         if (dcon->mono == enable_mono)
177                 return 0;
178 
179         dcon->mono = enable_mono;
180 
181         if (enable_mono) {
182                 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
183                 dcon->disp_mode |= MODE_MONO_LUMA;
184         } else {
185                 dcon->disp_mode &= ~(MODE_MONO_LUMA);
186                 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
187         }
188 
189         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
190         return 0;
191 }
192 
193 /* For now, this will be really stupid - we need to address how
194  * DCONLOAD works in a sleep and account for it accordingly
195  */
196 
197 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
198 {
199         int x;
200 
201         /* Turn off the backlight and put the DCON to sleep */
202 
203         if (dcon->asleep == sleep)
204                 return;
205 
206         if (!olpc_board_at_least(olpc_board(0xc2)))
207                 return;
208 
209         if (sleep) {
210                 u8 pm = 0;
211 
212                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
213                 if (x)
214                         pr_warn("unable to force dcon to power down: %d!\n", x);
215                 else
216                         dcon->asleep = sleep;
217         } else {
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);
222                 if (x)
223                         pr_warn("unable to reinit dcon hardware: %d!\n", x);
224                 else
225                         dcon->asleep = sleep;
226 
227                 /* Restore backlight */
228                 dcon_set_backlight(dcon, dcon->bl_val);
229         }
230 
231         /* We should turn off some stuff in the framebuffer - but what? */
232 }
233 
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
237  * delay here.
238  */
239 static void dcon_load_holdoff(struct dcon_priv *dcon)
240 {
241         struct timespec delta_t, now;
242 
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 
403         return sprintf(buf, "%4.4X\n", dcon->disp_mode);
404 }
405 
406 static ssize_t dcon_sleep_show(struct device *dev,
407         struct device_attribute *attr, char *buf)
408 {
409         struct dcon_priv *dcon = dev_get_drvdata(dev);
410 
411         return sprintf(buf, "%d\n", dcon->asleep);
412 }
413 
414 static ssize_t dcon_freeze_show(struct device *dev,
415         struct device_attribute *attr, char *buf)
416 {
417         struct dcon_priv *dcon = dev_get_drvdata(dev);
418 
419         return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
420 }
421 
422 static ssize_t dcon_mono_show(struct device *dev,
423         struct device_attribute *attr, char *buf)
424 {
425         struct dcon_priv *dcon = dev_get_drvdata(dev);
426 
427         return sprintf(buf, "%d\n", dcon->mono);
428 }
429 
430 static ssize_t dcon_resumeline_show(struct device *dev,
431         struct device_attribute *attr, char *buf)
432 {
433         return sprintf(buf, "%d\n", resumeline);
434 }
435 
436 static ssize_t dcon_mono_store(struct device *dev,
437         struct device_attribute *attr, const char *buf, size_t count)
438 {
439         unsigned long enable_mono;
440         int rc;
441 
442         rc = kstrtoul(buf, 10, &enable_mono);
443         if (rc)
444                 return rc;
445 
446         dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
447 
448         return count;
449 }
450 
451 static ssize_t dcon_freeze_store(struct device *dev,
452         struct device_attribute *attr, const char *buf, size_t count)
453 {
454         struct dcon_priv *dcon = dev_get_drvdata(dev);
455         unsigned long output;
456         int ret;
457 
458         ret = kstrtoul(buf, 10, &output);
459         if (ret)
460                 return ret;
461 
462         pr_info("dcon_freeze_store: %lu\n", output);
463 
464         switch (output) {
465         case 0:
466                 dcon_set_source(dcon, DCON_SOURCE_CPU);
467                 break;
468         case 1:
469                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
470                 break;
471         case 2:  /* normally unused */
472                 dcon_set_source(dcon, DCON_SOURCE_DCON);
473                 break;
474         default:
475                 return -EINVAL;
476         }
477 
478         return count;
479 }
480 
481 static ssize_t dcon_resumeline_store(struct device *dev,
482         struct device_attribute *attr, const char *buf, size_t count)
483 {
484         unsigned short rl;
485         int rc;
486 
487         rc = kstrtou16(buf, 10, &rl);
488         if (rc)
489                 return rc;
490 
491         resumeline = rl;
492         dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
493 
494         return count;
495 }
496 
497 static ssize_t dcon_sleep_store(struct device *dev,
498         struct device_attribute *attr, const char *buf, size_t count)
499 {
500         unsigned long output;
501         int ret;
502 
503         ret = kstrtoul(buf, 10, &output);
504         if (ret)
505                 return ret;
506 
507         dcon_sleep(dev_get_drvdata(dev), output ? true : false);
508         return count;
509 }
510 
511 static struct device_attribute dcon_device_files[] = {
512         __ATTR(mode, 0444, dcon_mode_show, NULL),
513         __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
514         __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
515         __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
516         __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
517 };
518 
519 static int dcon_bl_update(struct backlight_device *dev)
520 {
521         struct dcon_priv *dcon = bl_get_data(dev);
522         u8 level = dev->props.brightness & 0x0F;
523 
524         if (dev->props.power != FB_BLANK_UNBLANK)
525                 level = 0;
526 
527         if (level != dcon->bl_val)
528                 dcon_set_backlight(dcon, level);
529 
530         /* power down the DCON when the screen is blanked */
531         if (!dcon->ignore_fb_events)
532                 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
533 
534         return 0;
535 }
536 
537 static int dcon_bl_get(struct backlight_device *dev)
538 {
539         struct dcon_priv *dcon = bl_get_data(dev);
540 
541         return dcon->bl_val;
542 }
543 
544 static const struct backlight_ops dcon_bl_ops = {
545         .update_status = dcon_bl_update,
546         .get_brightness = dcon_bl_get,
547 };
548 
549 static struct backlight_properties dcon_bl_props = {
550         .max_brightness = 15,
551         .type = BACKLIGHT_RAW,
552         .power = FB_BLANK_UNBLANK,
553 };
554 
555 static int dcon_reboot_notify(struct notifier_block *nb,
556                               unsigned long foo, void *bar)
557 {
558         struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
559 
560         if (!dcon || !dcon->client)
561                 return NOTIFY_DONE;
562 
563         /* Turn off the DCON. Entirely. */
564         dcon_write(dcon, DCON_REG_MODE, 0x39);
565         dcon_write(dcon, DCON_REG_MODE, 0x32);
566         return NOTIFY_DONE;
567 }
568 
569 static int unfreeze_on_panic(struct notifier_block *nb,
570                              unsigned long e, void *p)
571 {
572         pdata->set_dconload(1);
573         return NOTIFY_DONE;
574 }
575 
576 static struct notifier_block dcon_panic_nb = {
577         .notifier_call = unfreeze_on_panic,
578 };
579 
580 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
581 {
582         strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
583 
584         return 0;
585 }
586 
587 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
588 {
589         struct dcon_priv *dcon;
590         int rc, i, j;
591 
592         if (!pdata)
593                 return -ENXIO;
594 
595         dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
596         if (!dcon)
597                 return -ENOMEM;
598 
599         dcon->client = client;
600         init_waitqueue_head(&dcon->waitq);
601         INIT_WORK(&dcon->switch_source, dcon_source_switch);
602         dcon->reboot_nb.notifier_call = dcon_reboot_notify;
603         dcon->reboot_nb.priority = -1;
604 
605         i2c_set_clientdata(client, dcon);
606 
607         if (num_registered_fb < 1) {
608                 dev_err(&client->dev, "DCON driver requires a registered fb\n");
609                 rc = -EIO;
610                 goto einit;
611         }
612         dcon->fbinfo = registered_fb[0];
613 
614         rc = dcon_hw_init(dcon, 1);
615         if (rc)
616                 goto einit;
617 
618         /* Add the DCON device */
619 
620         dcon_device = platform_device_alloc("dcon", -1);
621 
622         if (dcon_device == NULL) {
623                 pr_err("Unable to create the DCON device\n");
624                 rc = -ENOMEM;
625                 goto eirq;
626         }
627         rc = platform_device_add(dcon_device);
628         platform_set_drvdata(dcon_device, dcon);
629 
630         if (rc) {
631                 pr_err("Unable to add the DCON device\n");
632                 goto edev;
633         }
634 
635         for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
636                 rc = device_create_file(&dcon_device->dev,
637                                         &dcon_device_files[i]);
638                 if (rc) {
639                         dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
640                         goto ecreate;
641                 }
642         }
643 
644         dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
645 
646         /* Add the backlight device for the DCON */
647         dcon_bl_props.brightness = dcon->bl_val;
648         dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
649                 dcon, &dcon_bl_ops, &dcon_bl_props);
650         if (IS_ERR(dcon->bl_dev)) {
651                 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
652                                 PTR_ERR(dcon->bl_dev));
653                 dcon->bl_dev = NULL;
654         }
655 
656         register_reboot_notifier(&dcon->reboot_nb);
657         atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
658 
659         return 0;
660 
661  ecreate:
662         for (j = 0; j < i; j++)
663                 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
664  edev:
665         platform_device_unregister(dcon_device);
666         dcon_device = NULL;
667  eirq:
668         free_irq(DCON_IRQ, dcon);
669  einit:
670         kfree(dcon);
671         return rc;
672 }
673 
674 static int dcon_remove(struct i2c_client *client)
675 {
676         struct dcon_priv *dcon = i2c_get_clientdata(client);
677 
678         unregister_reboot_notifier(&dcon->reboot_nb);
679         atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
680 
681         free_irq(DCON_IRQ, dcon);
682 
683         backlight_device_unregister(dcon->bl_dev);
684 
685         if (dcon_device != NULL)
686                 platform_device_unregister(dcon_device);
687         cancel_work_sync(&dcon->switch_source);
688 
689         kfree(dcon);
690 
691         return 0;
692 }
693 
694 #ifdef CONFIG_PM
695 static int dcon_suspend(struct device *dev)
696 {
697         struct i2c_client *client = to_i2c_client(dev);
698         struct dcon_priv *dcon = i2c_get_clientdata(client);
699 
700         if (!dcon->asleep) {
701                 /* Set up the DCON to have the source */
702                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
703         }
704 
705         return 0;
706 }
707 
708 static int dcon_resume(struct device *dev)
709 {
710         struct i2c_client *client = to_i2c_client(dev);
711         struct dcon_priv *dcon = i2c_get_clientdata(client);
712 
713         if (!dcon->asleep) {
714                 dcon_bus_stabilize(dcon, 0);
715                 dcon_set_source(dcon, DCON_SOURCE_CPU);
716         }
717 
718         return 0;
719 }
720 
721 #else
722 
723 #define dcon_suspend NULL
724 #define dcon_resume NULL
725 
726 #endif /* CONFIG_PM */
727 
728 
729 irqreturn_t dcon_interrupt(int irq, void *id)
730 {
731         struct dcon_priv *dcon = id;
732         u8 status;
733 
734         if (pdata->read_status(&status))
735                 return IRQ_NONE;
736 
737         switch (status & 3) {
738         case 3:
739                 pr_debug("DCONLOAD_MISSED interrupt\n");
740                 break;
741 
742         case 2: /* switch to DCON mode */
743         case 1: /* switch to CPU mode */
744                 dcon->switched = true;
745                 getnstimeofday(&dcon->irq_time);
746                 wake_up(&dcon->waitq);
747                 break;
748 
749         case 0:
750                 /* workaround resume case:  the DCON (on 1.5) doesn't
751                  * ever assert status 0x01 when switching to CPU mode
752                  * during resume.  this is because DCONLOAD is de-asserted
753                  * _immediately_ upon exiting S3, so the actual release
754                  * of the DCON happened long before this point.
755                  * see http://dev.laptop.org/ticket/9869
756                  */
757                 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
758                         dcon->switched = true;
759                         getnstimeofday(&dcon->irq_time);
760                         wake_up(&dcon->waitq);
761                         pr_debug("switching w/ status 0/0\n");
762                 } else {
763                         pr_debug("scanline interrupt w/CPU\n");
764                 }
765         }
766 
767         return IRQ_HANDLED;
768 }
769 
770 static const struct dev_pm_ops dcon_pm_ops = {
771         .suspend = dcon_suspend,
772         .resume = dcon_resume,
773 };
774 
775 static const struct i2c_device_id dcon_idtable[] = {
776         { "olpc_dcon",  0 },
777         { }
778 };
779 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
780 
781 static struct i2c_driver dcon_driver = {
782         .driver = {
783                 .name   = "olpc_dcon",
784                 .pm = &dcon_pm_ops,
785         },
786         .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
787         .id_table = dcon_idtable,
788         .probe = dcon_probe,
789         .remove = dcon_remove,
790         .detect = dcon_detect,
791         .address_list = normal_i2c,
792 };
793 
794 static int __init olpc_dcon_init(void)
795 {
796 #ifdef CONFIG_FB_OLPC_DCON_1_5
797         /* XO-1.5 */
798         if (olpc_board_at_least(olpc_board(0xd0)))
799                 pdata = &dcon_pdata_xo_1_5;
800 #endif
801 #ifdef CONFIG_FB_OLPC_DCON_1
802         if (!pdata)
803                 pdata = &dcon_pdata_xo_1;
804 #endif
805 
806         return i2c_add_driver(&dcon_driver);
807 }
808 
809 static void __exit olpc_dcon_exit(void)
810 {
811         i2c_del_driver(&dcon_driver);
812 }
813 
814 module_init(olpc_dcon_init);
815 module_exit(olpc_dcon_exit);
816 
817 MODULE_LICENSE("GPL");
818 

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