kernel/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         u16 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         /* Set the scanline to interrupt on during resume */
 104         dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
 105
 106 err:
 107         return rc;
 108 }
 109
 110 /*
 111  * The smbus doesn't always come back due to what is believed to be
 112  * hardware (power rail) bugs.  For older models where this is known to
 113  * occur, our solution is to attempt to wait for the bus to stabilize;
 114  * if it doesn't happen, cut power to the dcon, repower it, and wait
 115  * for the bus to stabilize.  Rinse, repeat until we have a working
 116  * smbus.  For newer models, we simply BUG(); we want to know if this
 117  * still happens despite the power fixes that have been made!
 118  */
 119 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
 120 {
 121         unsigned long timeout;
 122         u8 pm;
 123         int x;
 124
 125 power_up:
 126         if (is_powered_down) {
 127                 pm = 1;
 128                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
 129                 if (x) {
 130                         pr_warn("unable to force dcon to power up: %d!\n", x);
 131                         return x;
 132                 }
 133                 usleep_range(10000, 11000);  /* we'll be conservative */
 134         }
 135
 136         pdata->bus_stabilize_wiggle();
 137
 138         for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
 139                 usleep_range(1000, 1100);
 140                 x = dcon_read(dcon, DCON_REG_ID);
 141         }
 142         if (x < 0) {
 143                 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
 144                 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
 145                 pm = 0;
 146                 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
 147                 msleep(100);
 148                 is_powered_down = 1;
 149                 goto power_up;  /* argh, stupid hardware.. */
 150         }
 151
 152         if (is_powered_down)
 153                 return dcon_hw_init(dcon, 0);
 154         return 0;
 155 }
 156
 157 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
 158 {
 159         dcon->bl_val = level;
 160         dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
 161
 162         /* Purposely turn off the backlight when we go to level 0 */
 163         if (dcon->bl_val == 0) {
 164                 dcon->disp_mode &= ~MODE_BL_ENABLE;
 165                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 166         } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
 167                 dcon->disp_mode |= MODE_BL_ENABLE;
 168                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 169         }
 170 }
 171
 172 /* Set the output type to either color or mono */
 173 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
 174 {
 175         if (dcon->mono == enable_mono)
 176                 return 0;
 177
 178         dcon->mono = enable_mono;
 179
 180         if (enable_mono) {
 181                 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
 182                 dcon->disp_mode |= MODE_MONO_LUMA;
 183         } else {
 184                 dcon->disp_mode &= ~(MODE_MONO_LUMA);
 185                 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
 186         }
 187
 188         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 189         return 0;
 190 }
 191
 192 /* For now, this will be really stupid - we need to address how
 193  * DCONLOAD works in a sleep and account for it accordingly
 194  */
 195
 196 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
 197 {
 198         int x;
 199
 200         /* Turn off the backlight and put the DCON to sleep */
 201
 202         if (dcon->asleep == sleep)
 203                 return;
 204
 205         if (!olpc_board_at_least(olpc_board(0xc2)))
 206                 return;
 207
 208         if (sleep) {
 209                 u8 pm = 0;
 210
 211                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
 212                 if (x)
 213                         pr_warn("unable to force dcon to power down: %d!\n", x);
 214                 else
 215                         dcon->asleep = sleep;
 216         } else {
 217                 /* Only re-enable the backlight if the backlight value is set */
 218                 if (dcon->bl_val != 0)
 219                         dcon->disp_mode |= MODE_BL_ENABLE;
 220                 x = dcon_bus_stabilize(dcon, 1);
 221                 if (x)
 222                         pr_warn("unable to reinit dcon hardware: %d!\n", x);
 223                 else
 224                         dcon->asleep = sleep;
 225
 226                 /* Restore backlight */
 227                 dcon_set_backlight(dcon, dcon->bl_val);
 228         }
 229
 230         /* We should turn off some stuff in the framebuffer - but what? */
 231 }
 232
 233 /* the DCON seems to get confused if we change DCONLOAD too
 234  * frequently -- i.e., approximately faster than frame time.
 235  * normally we don't change it this fast, so in general we won't
 236  * delay here.
 237  */
 238 static void dcon_load_holdoff(struct dcon_priv *dcon)
 239 {
 240         ktime_t delta_t, now;
 241
 242         while (1) {
 243                 now = ktime_get();
 244                 delta_t = ktime_sub(now, dcon->load_time);
 245                 if (ktime_to_ns(delta_t) > NSEC_PER_MSEC * 20)
 246                         break;
 247                 mdelay(4);
 248         }
 249 }
 250
 251 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
 252 {
 253         int err;
 254
 255         console_lock();
 256         if (!lock_fb_info(dcon->fbinfo)) {
 257                 console_unlock();
 258                 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
 259                 return false;
 260         }
 261
 262         dcon->ignore_fb_events = true;
 263         err = fb_blank(dcon->fbinfo,
 264                         blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
 265         dcon->ignore_fb_events = false;
 266         unlock_fb_info(dcon->fbinfo);
 267         console_unlock();
 268
 269         if (err) {
 270                 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
 271                                 blank ? "" : "un");
 272                 return false;
 273         }
 274         return true;
 275 }
 276
 277 /* Set the source of the display (CPU or DCON) */
 278 static void dcon_source_switch(struct work_struct *work)
 279 {
 280         struct dcon_priv *dcon = container_of(work, struct dcon_priv,
 281                         switch_source);
 282         int source = dcon->pending_src;
 283
 284         if (dcon->curr_src == source)
 285                 return;
 286
 287         dcon_load_holdoff(dcon);
 288
 289         dcon->switched = false;
 290
 291         switch (source) {
 292         case DCON_SOURCE_CPU:
 293                 pr_info("dcon_source_switch to CPU\n");
 294                 /* Enable the scanline interrupt bit */
 295                 if (dcon_write(dcon, DCON_REG_MODE,
 296                                 dcon->disp_mode | MODE_SCAN_INT))
 297                         pr_err("couldn't enable scanline interrupt!\n");
 298                 else
 299                         /* Wait up to one second for the scanline interrupt */
 300                         wait_event_timeout(dcon->waitq, dcon->switched, HZ);
 301
 302                 if (!dcon->switched)
 303                         pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
 304
 305                 /* Turn off the scanline interrupt */
 306                 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
 307                         pr_err("couldn't disable scanline interrupt!\n");
 308
 309                 /*
 310                  * Ideally we'd like to disable interrupts here so that the
 311                  * fb unblanking and DCON turn on happen at a known time value;
 312                  * however, we can't do that right now with fb_blank
 313                  * messing with semaphores.
 314                  *
 315                  * For now, we just hope..
 316                  */
 317                 if (!dcon_blank_fb(dcon, false)) {
 318                         pr_err("Failed to enter CPU mode\n");
 319                         dcon->pending_src = DCON_SOURCE_DCON;
 320                         return;
 321                 }
 322
 323                 /* And turn off the DCON */
 324                 pdata->set_dconload(1);
 325                 dcon->load_time = ktime_get();
 326
 327                 pr_info("The CPU has control\n");
 328                 break;
 329         case DCON_SOURCE_DCON:
 330         {
 331                 ktime_t delta_t;
 332
 333                 pr_info("dcon_source_switch to DCON\n");
 334
 335                 /* Clear DCONLOAD - this implies that the DCON is in control */
 336                 pdata->set_dconload(0);
 337                 dcon->load_time = ktime_get();
 338
 339                 wait_event_timeout(dcon->waitq, dcon->switched, HZ/2);
 340
 341                 if (!dcon->switched) {
 342                         pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
 343                 } else {
 344                         /* sometimes the DCON doesn't follow its own rules,
 345                          * and doesn't wait for two vsync pulses before
 346                          * ack'ing the frame load with an IRQ.  the result
 347                          * is that the display shows the *previously*
 348                          * loaded frame.  we can detect this by looking at
 349                          * the time between asserting DCONLOAD and the IRQ --
 350                          * if it's less than 20msec, then the DCON couldn't
 351                          * have seen two VSYNC pulses.  in that case we
 352                          * deassert and reassert, and hope for the best.
 353                          * see http://dev.laptop.org/ticket/9664
 354                          */
 355                         delta_t = ktime_sub(dcon->irq_time, dcon->load_time);
 356                         if (dcon->switched && ktime_to_ns(delta_t)
 357                             < NSEC_PER_MSEC * 20) {
 358                                 pr_err("missed loading, retrying\n");
 359                                 pdata->set_dconload(1);
 360                                 mdelay(41);
 361                                 pdata->set_dconload(0);
 362                                 dcon->load_time = ktime_get();
 363                                 mdelay(41);
 364                         }
 365                 }
 366
 367                 dcon_blank_fb(dcon, true);
 368                 pr_info("The DCON has control\n");
 369                 break;
 370         }
 371         default:
 372                 BUG();
 373         }
 374
 375         dcon->curr_src = source;
 376 }
 377
 378 static void dcon_set_source(struct dcon_priv *dcon, int arg)
 379 {
 380         if (dcon->pending_src == arg)
 381                 return;
 382
 383         dcon->pending_src = arg;
 384
 385         if (dcon->curr_src != arg)
 386                 schedule_work(&dcon->switch_source);
 387 }
 388
 389 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
 390 {
 391         dcon_set_source(dcon, arg);
 392         flush_scheduled_work();
 393 }
 394
 395 static ssize_t dcon_mode_show(struct device *dev,
 396         struct device_attribute *attr, char *buf)
 397 {
 398         struct dcon_priv *dcon = dev_get_drvdata(dev);
 399
 400         return sprintf(buf, "%4.4X\n", dcon->disp_mode);
 401 }
 402
 403 static ssize_t dcon_sleep_show(struct device *dev,
 404         struct device_attribute *attr, char *buf)
 405 {
 406         struct dcon_priv *dcon = dev_get_drvdata(dev);
 407
 408         return sprintf(buf, "%d\n", dcon->asleep);
 409 }
 410
 411 static ssize_t dcon_freeze_show(struct device *dev,
 412         struct device_attribute *attr, char *buf)
 413 {
 414         struct dcon_priv *dcon = dev_get_drvdata(dev);
 415
 416         return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
 417 }
 418
 419 static ssize_t dcon_mono_show(struct device *dev,
 420         struct device_attribute *attr, char *buf)
 421 {
 422         struct dcon_priv *dcon = dev_get_drvdata(dev);
 423
 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
 538         return dcon->bl_val;
 539 }
 540
 541 static const struct backlight_ops dcon_bl_ops = {
 542         .update_status = dcon_bl_update,
 543         .get_brightness = dcon_bl_get,
 544 };
 545
 546 static struct backlight_properties dcon_bl_props = {
 547         .max_brightness = 15,
 548         .type = BACKLIGHT_RAW,
 549         .power = FB_BLANK_UNBLANK,
 550 };
 551
 552 static int dcon_reboot_notify(struct notifier_block *nb,
 553                               unsigned long foo, void *bar)
 554 {
 555         struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
 556
 557         if (!dcon || !dcon->client)
 558                 return NOTIFY_DONE;
 559
 560         /* Turn off the DCON. Entirely. */
 561         dcon_write(dcon, DCON_REG_MODE, 0x39);
 562         dcon_write(dcon, DCON_REG_MODE, 0x32);
 563         return NOTIFY_DONE;
 564 }
 565
 566 static int unfreeze_on_panic(struct notifier_block *nb,
 567                              unsigned long e, void *p)
 568 {
 569         pdata->set_dconload(1);
 570         return NOTIFY_DONE;
 571 }
 572
 573 static struct notifier_block dcon_panic_nb = {
 574         .notifier_call = unfreeze_on_panic,
 575 };
 576
 577 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
 578 {
 579         strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
 580
 581         return 0;
 582 }
 583
 584 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
 585 {
 586         struct dcon_priv *dcon;
 587         int rc, i, j;
 588
 589         if (!pdata)
 590                 return -ENXIO;
 591
 592         dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
 593         if (!dcon)
 594                 return -ENOMEM;
 595
 596         dcon->client = client;
 597         init_waitqueue_head(&dcon->waitq);
 598         INIT_WORK(&dcon->switch_source, dcon_source_switch);
 599         dcon->reboot_nb.notifier_call = dcon_reboot_notify;
 600         dcon->reboot_nb.priority = -1;
 601
 602         i2c_set_clientdata(client, dcon);
 603
 604         if (num_registered_fb < 1) {
 605                 dev_err(&client->dev, "DCON driver requires a registered fb\n");
 606                 rc = -EIO;
 607                 goto einit;
 608         }
 609         dcon->fbinfo = registered_fb[0];
 610
 611         rc = dcon_hw_init(dcon, 1);
 612         if (rc)
 613                 goto einit;
 614
 615         /* Add the DCON device */
 616
 617         dcon_device = platform_device_alloc("dcon", -1);
 618
 619         if (!dcon_device) {
 620                 pr_err("Unable to create the DCON device\n");
 621                 rc = -ENOMEM;
 622                 goto eirq;
 623         }
 624         rc = platform_device_add(dcon_device);
 625         platform_set_drvdata(dcon_device, dcon);
 626
 627         if (rc) {
 628                 pr_err("Unable to add the DCON device\n");
 629                 goto edev;
 630         }
 631
 632         for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
 633                 rc = device_create_file(&dcon_device->dev,
 634                                         &dcon_device_files[i]);
 635                 if (rc) {
 636                         dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
 637                         goto ecreate;
 638                 }
 639         }
 640
 641         dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
 642
 643         /* Add the backlight device for the DCON */
 644         dcon_bl_props.brightness = dcon->bl_val;
 645         dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
 646                 dcon, &dcon_bl_ops, &dcon_bl_props);
 647         if (IS_ERR(dcon->bl_dev)) {
 648                 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
 649                                 PTR_ERR(dcon->bl_dev));
 650                 dcon->bl_dev = NULL;
 651         }
 652
 653         register_reboot_notifier(&dcon->reboot_nb);
 654         atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
 655
 656         return 0;
 657
 658  ecreate:
 659         for (j = 0; j < i; j++)
 660                 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
 661  edev:
 662         platform_device_unregister(dcon_device);
 663         dcon_device = NULL;
 664  eirq:
 665         free_irq(DCON_IRQ, dcon);
 666  einit:
 667         kfree(dcon);
 668         return rc;
 669 }
 670
 671 static int dcon_remove(struct i2c_client *client)
 672 {
 673         struct dcon_priv *dcon = i2c_get_clientdata(client);
 674
 675         unregister_reboot_notifier(&dcon->reboot_nb);
 676         atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
 677
 678         free_irq(DCON_IRQ, dcon);
 679
 680         backlight_device_unregister(dcon->bl_dev);
 681
 682         if (dcon_device)
 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 irqreturn_t dcon_interrupt(int irq, void *id)
 726 {
 727         struct dcon_priv *dcon = id;
 728         u8 status;
 729
 730         if (pdata->read_status(&status))
 731                 return IRQ_NONE;
 732
 733         switch (status & 3) {
 734         case 3:
 735                 pr_debug("DCONLOAD_MISSED interrupt\n");
 736                 break;
 737
 738         case 2: /* switch to DCON mode */
 739         case 1: /* switch to CPU mode */
 740                 dcon->switched = true;
 741                 dcon->irq_time = ktime_get();
 742                 wake_up(&dcon->waitq);
 743                 break;
 744
 745         case 0:
 746                 /* workaround resume case:  the DCON (on 1.5) doesn't
 747                  * ever assert status 0x01 when switching to CPU mode
 748                  * during resume.  this is because DCONLOAD is de-asserted
 749                  * _immediately_ upon exiting S3, so the actual release
 750                  * of the DCON happened long before this point.
 751                  * see http://dev.laptop.org/ticket/9869
 752                  */
 753                 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
 754                         dcon->switched = true;
 755                         dcon->irq_time = ktime_get();
 756                         wake_up(&dcon->waitq);
 757                         pr_debug("switching w/ status 0/0\n");
 758                 } else {
 759                         pr_debug("scanline interrupt w/CPU\n");
 760                 }
 761         }
 762
 763         return IRQ_HANDLED;
 764 }
 765
 766 static const struct dev_pm_ops dcon_pm_ops = {
 767         .suspend = dcon_suspend,
 768         .resume = dcon_resume,
 769 };
 770
 771 static const struct i2c_device_id dcon_idtable[] = {
 772         { "olpc_dcon",  0 },
 773         { }
 774 };
 775 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
 776
 777 static struct i2c_driver dcon_driver = {
 778         .driver = {
 779                 .name   = "olpc_dcon",
 780                 .pm = &dcon_pm_ops,
 781         },
 782         .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
 783         .id_table = dcon_idtable,
 784         .probe = dcon_probe,
 785         .remove = dcon_remove,
 786         .detect = dcon_detect,
 787         .address_list = normal_i2c,
 788 };
 789
 790 static int __init olpc_dcon_init(void)
 791 {
 792 #ifdef CONFIG_FB_OLPC_DCON_1_5
 793         /* XO-1.5 */
 794         if (olpc_board_at_least(olpc_board(0xd0)))
 795                 pdata = &dcon_pdata_xo_1_5;
 796 #endif
 797 #ifdef CONFIG_FB_OLPC_DCON_1
 798         if (!pdata)
 799                 pdata = &dcon_pdata_xo_1;
 800 #endif
 801
 802         return i2c_add_driver(&dcon_driver);
 803 }
 804
 805 static void __exit olpc_dcon_exit(void)
 806 {
 807         i2c_del_driver(&dcon_driver);
 808 }
 809
 810 module_init(olpc_dcon_init);
 811 module_exit(olpc_dcon_exit);
 812
 813 MODULE_LICENSE("GPL");