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
 214                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
 215                 if (x)
 216                         pr_warn("unable to force dcon to power down: %d!\n", x);
 217                 else
 218                         dcon->asleep = sleep;
 219         } else {
 220                 /* Only re-enable the backlight if the backlight value is set */
 221                 if (dcon->bl_val != 0)
 222                         dcon->disp_mode |= MODE_BL_ENABLE;
 223                 x = dcon_bus_stabilize(dcon, 1);
 224                 if (x)
 225                         pr_warn("unable to reinit dcon hardware: %d!\n", x);
 226                 else
 227                         dcon->asleep = sleep;
 228
 229                 /* Restore backlight */
 230                 dcon_set_backlight(dcon, dcon->bl_val);
 231         }
 232
 233         /* We should turn off some stuff in the framebuffer - but what? */
 234 }
 235
 236 /* the DCON seems to get confused if we change DCONLOAD too
 237  * frequently -- i.e., approximately faster than frame time.
 238  * normally we don't change it this fast, so in general we won't
 239  * delay here.
 240  */
 241 static void dcon_load_holdoff(struct dcon_priv *dcon)
 242 {
 243         struct timespec delta_t, now;
 244
 245         while (1) {
 246                 getnstimeofday(&now);
 247                 delta_t = timespec_sub(now, dcon->load_time);
 248                 if (delta_t.tv_sec != 0 ||
 249                         delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
 250                         break;
 251                 }
 252                 mdelay(4);
 253         }
 254 }
 255
 256 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
 257 {
 258         int err;
 259
 260         console_lock();
 261         if (!lock_fb_info(dcon->fbinfo)) {
 262                 console_unlock();
 263                 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
 264                 return false;
 265         }
 266
 267         dcon->ignore_fb_events = true;
 268         err = fb_blank(dcon->fbinfo,
 269                         blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
 270         dcon->ignore_fb_events = false;
 271         unlock_fb_info(dcon->fbinfo);
 272         console_unlock();
 273
 274         if (err) {
 275                 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
 276                                 blank ? "" : "un");
 277                 return false;
 278         }
 279         return true;
 280 }
 281
 282 /* Set the source of the display (CPU or DCON) */
 283 static void dcon_source_switch(struct work_struct *work)
 284 {
 285         struct dcon_priv *dcon = container_of(work, struct dcon_priv,
 286                         switch_source);
 287         int source = dcon->pending_src;
 288
 289         if (dcon->curr_src == source)
 290                 return;
 291
 292         dcon_load_holdoff(dcon);
 293
 294         dcon->switched = false;
 295
 296         switch (source) {
 297         case DCON_SOURCE_CPU:
 298                 pr_info("dcon_source_switch to CPU\n");
 299                 /* Enable the scanline interrupt bit */
 300                 if (dcon_write(dcon, DCON_REG_MODE,
 301                                 dcon->disp_mode | MODE_SCAN_INT))
 302                         pr_err("couldn't enable scanline interrupt!\n");
 303                 else
 304                         /* Wait up to one second for the scanline interrupt */
 305                         wait_event_timeout(dcon->waitq, dcon->switched, HZ);
 306
 307                 if (!dcon->switched)
 308                         pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
 309
 310                 /* Turn off the scanline interrupt */
 311                 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
 312                         pr_err("couldn't disable scanline interrupt!\n");
 313
 314                 /*
 315                  * Ideally we'd like to disable interrupts here so that the
 316                  * fb unblanking and DCON turn on happen at a known time value;
 317                  * however, we can't do that right now with fb_blank
 318                  * messing with semaphores.
 319                  *
 320                  * For now, we just hope..
 321                  */
 322                 if (!dcon_blank_fb(dcon, false)) {
 323                         pr_err("Failed to enter CPU mode\n");
 324                         dcon->pending_src = DCON_SOURCE_DCON;
 325                         return;
 326                 }
 327
 328                 /* And turn off the DCON */
 329                 pdata->set_dconload(1);
 330                 getnstimeofday(&dcon->load_time);
 331
 332                 pr_info("The CPU has control\n");
 333                 break;
 334         case DCON_SOURCE_DCON:
 335         {
 336                 struct timespec delta_t;
 337
 338                 pr_info("dcon_source_switch to DCON\n");
 339
 340                 /* Clear DCONLOAD - this implies that the DCON is in control */
 341                 pdata->set_dconload(0);
 342                 getnstimeofday(&dcon->load_time);
 343
 344                 wait_event_timeout(dcon->waitq, dcon->switched, HZ/2);
 345
 346                 if (!dcon->switched) {
 347                         pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
 348                 } else {
 349                         /* sometimes the DCON doesn't follow its own rules,
 350                          * and doesn't wait for two vsync pulses before
 351                          * ack'ing the frame load with an IRQ.  the result
 352                          * is that the display shows the *previously*
 353                          * loaded frame.  we can detect this by looking at
 354                          * the time between asserting DCONLOAD and the IRQ --
 355                          * if it's less than 20msec, then the DCON couldn't
 356                          * have seen two VSYNC pulses.  in that case we
 357                          * deassert and reassert, and hope for the best.
 358                          * see http://dev.laptop.org/ticket/9664
 359                          */
 360                         delta_t = timespec_sub(dcon->irq_time, dcon->load_time);
 361                         if (dcon->switched && delta_t.tv_sec == 0 &&
 362                                         delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
 363                                 pr_err("missed loading, retrying\n");
 364                                 pdata->set_dconload(1);
 365                                 mdelay(41);
 366                                 pdata->set_dconload(0);
 367                                 getnstimeofday(&dcon->load_time);
 368                                 mdelay(41);
 369                         }
 370                 }
 371
 372                 dcon_blank_fb(dcon, true);
 373                 pr_info("The DCON has control\n");
 374                 break;
 375         }
 376         default:
 377                 BUG();
 378         }
 379
 380         dcon->curr_src = source;
 381 }
 382
 383 static void dcon_set_source(struct dcon_priv *dcon, int arg)
 384 {
 385         if (dcon->pending_src == arg)
 386                 return;
 387
 388         dcon->pending_src = arg;
 389
 390         if (dcon->curr_src != arg)
 391                 schedule_work(&dcon->switch_source);
 392 }
 393
 394 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
 395 {
 396         dcon_set_source(dcon, arg);
 397         flush_scheduled_work();
 398 }
 399
 400 static ssize_t dcon_mode_show(struct device *dev,
 401         struct device_attribute *attr, char *buf)
 402 {
 403         struct dcon_priv *dcon = dev_get_drvdata(dev);
 404
 405         return sprintf(buf, "%4.4X\n", dcon->disp_mode);
 406 }
 407
 408 static ssize_t dcon_sleep_show(struct device *dev,
 409         struct device_attribute *attr, char *buf)
 410 {
 411         struct dcon_priv *dcon = dev_get_drvdata(dev);
 412
 413         return sprintf(buf, "%d\n", dcon->asleep);
 414 }
 415
 416 static ssize_t dcon_freeze_show(struct device *dev,
 417         struct device_attribute *attr, char *buf)
 418 {
 419         struct dcon_priv *dcon = dev_get_drvdata(dev);
 420
 421         return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
 422 }
 423
 424 static ssize_t dcon_mono_show(struct device *dev,
 425         struct device_attribute *attr, char *buf)
 426 {
 427         struct dcon_priv *dcon = dev_get_drvdata(dev);
 428
 429         return sprintf(buf, "%d\n", dcon->mono);
 430 }
 431
 432 static ssize_t dcon_resumeline_show(struct device *dev,
 433         struct device_attribute *attr, char *buf)
 434 {
 435         return sprintf(buf, "%d\n", resumeline);
 436 }
 437
 438 static ssize_t dcon_mono_store(struct device *dev,
 439         struct device_attribute *attr, const char *buf, size_t count)
 440 {
 441         unsigned long enable_mono;
 442         int rc;
 443
 444         rc = kstrtoul(buf, 10, &enable_mono);
 445         if (rc)
 446                 return rc;
 447
 448         dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
 449
 450         return count;
 451 }
 452
 453 static ssize_t dcon_freeze_store(struct device *dev,
 454         struct device_attribute *attr, const char *buf, size_t count)
 455 {
 456         struct dcon_priv *dcon = dev_get_drvdata(dev);
 457         unsigned long output;
 458         int ret;
 459
 460         ret = kstrtoul(buf, 10, &output);
 461         if (ret)
 462                 return ret;
 463
 464         pr_info("dcon_freeze_store: %lu\n", output);
 465
 466         switch (output) {
 467         case 0:
 468                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 469                 break;
 470         case 1:
 471                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 472                 break;
 473         case 2:  /* normally unused */
 474                 dcon_set_source(dcon, DCON_SOURCE_DCON);
 475                 break;
 476         default:
 477                 return -EINVAL;
 478         }
 479
 480         return count;
 481 }
 482
 483 static ssize_t dcon_resumeline_store(struct device *dev,
 484         struct device_attribute *attr, const char *buf, size_t count)
 485 {
 486         unsigned short rl;
 487         int rc;
 488
 489         rc = kstrtou16(buf, 10, &rl);
 490         if (rc)
 491                 return rc;
 492
 493         resumeline = rl;
 494         dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
 495
 496         return count;
 497 }
 498
 499 static ssize_t dcon_sleep_store(struct device *dev,
 500         struct device_attribute *attr, const char *buf, size_t count)
 501 {
 502         unsigned long output;
 503         int ret;
 504
 505         ret = kstrtoul(buf, 10, &output);
 506         if (ret)
 507                 return ret;
 508
 509         dcon_sleep(dev_get_drvdata(dev), output ? true : false);
 510         return count;
 511 }
 512
 513 static struct device_attribute dcon_device_files[] = {
 514         __ATTR(mode, 0444, dcon_mode_show, NULL),
 515         __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
 516         __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
 517         __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
 518         __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
 519 };
 520
 521 static int dcon_bl_update(struct backlight_device *dev)
 522 {
 523         struct dcon_priv *dcon = bl_get_data(dev);
 524         u8 level = dev->props.brightness & 0x0F;
 525
 526         if (dev->props.power != FB_BLANK_UNBLANK)
 527                 level = 0;
 528
 529         if (level != dcon->bl_val)
 530                 dcon_set_backlight(dcon, level);
 531
 532         /* power down the DCON when the screen is blanked */
 533         if (!dcon->ignore_fb_events)
 534                 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
 535
 536         return 0;
 537 }
 538
 539 static int dcon_bl_get(struct backlight_device *dev)
 540 {
 541         struct dcon_priv *dcon = bl_get_data(dev);
 542
 543         return dcon->bl_val;
 544 }
 545
 546 static const struct backlight_ops dcon_bl_ops = {
 547         .update_status = dcon_bl_update,
 548         .get_brightness = dcon_bl_get,
 549 };
 550
 551 static struct backlight_properties dcon_bl_props = {
 552         .max_brightness = 15,
 553         .type = BACKLIGHT_RAW,
 554         .power = FB_BLANK_UNBLANK,
 555 };
 556
 557 static int dcon_reboot_notify(struct notifier_block *nb,
 558                               unsigned long foo, void *bar)
 559 {
 560         struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
 561
 562         if (!dcon || !dcon->client)
 563                 return NOTIFY_DONE;
 564
 565         /* Turn off the DCON. Entirely. */
 566         dcon_write(dcon, DCON_REG_MODE, 0x39);
 567         dcon_write(dcon, DCON_REG_MODE, 0x32);
 568         return NOTIFY_DONE;
 569 }
 570
 571 static int unfreeze_on_panic(struct notifier_block *nb,
 572                              unsigned long e, void *p)
 573 {
 574         pdata->set_dconload(1);
 575         return NOTIFY_DONE;
 576 }
 577
 578 static struct notifier_block dcon_panic_nb = {
 579         .notifier_call = unfreeze_on_panic,
 580 };
 581
 582 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
 583 {
 584         strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
 585
 586         return 0;
 587 }
 588
 589 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
 590 {
 591         struct dcon_priv *dcon;
 592         int rc, i, j;
 593
 594         if (!pdata)
 595                 return -ENXIO;
 596
 597         dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
 598         if (!dcon)
 599                 return -ENOMEM;
 600
 601         dcon->client = client;
 602         init_waitqueue_head(&dcon->waitq);
 603         INIT_WORK(&dcon->switch_source, dcon_source_switch);
 604         dcon->reboot_nb.notifier_call = dcon_reboot_notify;
 605         dcon->reboot_nb.priority = -1;
 606
 607         i2c_set_clientdata(client, dcon);
 608
 609         if (num_registered_fb < 1) {
 610                 dev_err(&client->dev, "DCON driver requires a registered fb\n");
 611                 rc = -EIO;
 612                 goto einit;
 613         }
 614         dcon->fbinfo = registered_fb[0];
 615
 616         rc = dcon_hw_init(dcon, 1);
 617         if (rc)
 618                 goto einit;
 619
 620         /* Add the DCON device */
 621
 622         dcon_device = platform_device_alloc("dcon", -1);
 623
 624         if (dcon_device == NULL) {
 625                 pr_err("Unable to create the DCON device\n");
 626                 rc = -ENOMEM;
 627                 goto eirq;
 628         }
 629         rc = platform_device_add(dcon_device);
 630         platform_set_drvdata(dcon_device, dcon);
 631
 632         if (rc) {
 633                 pr_err("Unable to add the DCON device\n");
 634                 goto edev;
 635         }
 636
 637         for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
 638                 rc = device_create_file(&dcon_device->dev,
 639                                         &dcon_device_files[i]);
 640                 if (rc) {
 641                         dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
 642                         goto ecreate;
 643                 }
 644         }
 645
 646         dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
 647
 648         /* Add the backlight device for the DCON */
 649         dcon_bl_props.brightness = dcon->bl_val;
 650         dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
 651                 dcon, &dcon_bl_ops, &dcon_bl_props);
 652         if (IS_ERR(dcon->bl_dev)) {
 653                 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
 654                                 PTR_ERR(dcon->bl_dev));
 655                 dcon->bl_dev = NULL;
 656         }
 657
 658         register_reboot_notifier(&dcon->reboot_nb);
 659         atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
 660
 661         return 0;
 662
 663  ecreate:
 664         for (j = 0; j < i; j++)
 665                 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
 666  edev:
 667         platform_device_unregister(dcon_device);
 668         dcon_device = NULL;
 669  eirq:
 670         free_irq(DCON_IRQ, dcon);
 671  einit:
 672         kfree(dcon);
 673         return rc;
 674 }
 675
 676 static int dcon_remove(struct i2c_client *client)
 677 {
 678         struct dcon_priv *dcon = i2c_get_clientdata(client);
 679
 680         unregister_reboot_notifier(&dcon->reboot_nb);
 681         atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
 682
 683         free_irq(DCON_IRQ, dcon);
 684
 685         if (dcon->bl_dev)
 686                 backlight_device_unregister(dcon->bl_dev);
 687
 688         if (dcon_device != NULL)
 689                 platform_device_unregister(dcon_device);
 690         cancel_work_sync(&dcon->switch_source);
 691
 692         kfree(dcon);
 693
 694         return 0;
 695 }
 696
 697 #ifdef CONFIG_PM
 698 static int dcon_suspend(struct device *dev)
 699 {
 700         struct i2c_client *client = to_i2c_client(dev);
 701         struct dcon_priv *dcon = i2c_get_clientdata(client);
 702
 703         if (!dcon->asleep) {
 704                 /* Set up the DCON to have the source */
 705                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 706         }
 707
 708         return 0;
 709 }
 710
 711 static int dcon_resume(struct device *dev)
 712 {
 713         struct i2c_client *client = to_i2c_client(dev);
 714         struct dcon_priv *dcon = i2c_get_clientdata(client);
 715
 716         if (!dcon->asleep) {
 717                 dcon_bus_stabilize(dcon, 0);
 718                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 719         }
 720
 721         return 0;
 722 }
 723
 724 #else
 725
 726 #define dcon_suspend NULL
 727 #define dcon_resume NULL
 728
 729 #endif /* CONFIG_PM */
 730
 731
 732 irqreturn_t dcon_interrupt(int irq, void *id)
 733 {
 734         struct dcon_priv *dcon = id;
 735         u8 status;
 736
 737         if (pdata->read_status(&status))
 738                 return IRQ_NONE;
 739
 740         switch (status & 3) {
 741         case 3:
 742                 pr_debug("DCONLOAD_MISSED interrupt\n");
 743                 break;
 744
 745         case 2: /* switch to DCON mode */
 746         case 1: /* switch to CPU mode */
 747                 dcon->switched = true;
 748                 getnstimeofday(&dcon->irq_time);
 749                 wake_up(&dcon->waitq);
 750                 break;
 751
 752         case 0:
 753                 /* workaround resume case:  the DCON (on 1.5) doesn't
 754                  * ever assert status 0x01 when switching to CPU mode
 755                  * during resume.  this is because DCONLOAD is de-asserted
 756                  * _immediately_ upon exiting S3, so the actual release
 757                  * of the DCON happened long before this point.
 758                  * see http://dev.laptop.org/ticket/9869
 759                  */
 760                 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
 761                         dcon->switched = true;
 762                         getnstimeofday(&dcon->irq_time);
 763                         wake_up(&dcon->waitq);
 764                         pr_debug("switching w/ status 0/0\n");
 765                 } else {
 766                         pr_debug("scanline interrupt w/CPU\n");
 767                 }
 768         }
 769
 770         return IRQ_HANDLED;
 771 }
 772
 773 static const struct dev_pm_ops dcon_pm_ops = {
 774         .suspend = dcon_suspend,
 775         .resume = dcon_resume,
 776 };
 777
 778 static const struct i2c_device_id dcon_idtable[] = {
 779         { "olpc_dcon",  0 },
 780         { }
 781 };
 782 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
 783
 784 struct i2c_driver dcon_driver = {
 785         .driver = {
 786                 .name   = "olpc_dcon",
 787                 .pm = &dcon_pm_ops,
 788         },
 789         .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
 790         .id_table = dcon_idtable,
 791         .probe = dcon_probe,
 792         .remove = dcon_remove,
 793         .detect = dcon_detect,
 794         .address_list = normal_i2c,
 795 };
 796
 797 static int __init olpc_dcon_init(void)
 798 {
 799 #ifdef CONFIG_FB_OLPC_DCON_1_5
 800         /* XO-1.5 */
 801         if (olpc_board_at_least(olpc_board(0xd0)))
 802                 pdata = &dcon_pdata_xo_1_5;
 803 #endif
 804 #ifdef CONFIG_FB_OLPC_DCON_1
 805         if (!pdata)
 806                 pdata = &dcon_pdata_xo_1;
 807 #endif
 808
 809         return i2c_add_driver(&dcon_driver);
 810 }
 811
 812 static void __exit olpc_dcon_exit(void)
 813 {
 814         i2c_del_driver(&dcon_driver);
 815 }
 816
 817 module_init(olpc_dcon_init);
 818 module_exit(olpc_dcon_exit);
 819
 820 MODULE_LICENSE("GPL");