drivers/staging/olpc_dcon/olpc_dcon.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Mainly by David Woodhouse, somewhat modified by Jordan Crouse
   4  *
   5  * Copyright © 2006-2007  Red Hat, Inc.
   6  * Copyright © 2006-2007  Advanced Micro Devices, Inc.
   7  * Copyright © 2009       VIA Technology, Inc.
   8  * Copyright (c) 2010-2011  Andres Salomon <dilinger@queued.net>
   9  */
  10
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/kernel.h>
  14 #include <linux/fb.h>
  15 #include <linux/console.h>
  16 #include <linux/i2c.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/delay.h>
  20 #include <linux/module.h>
  21 #include <linux/backlight.h>
  22 #include <linux/device.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/ctype.h>
  25 #include <linux/panic_notifier.h>
  26 #include <linux/reboot.h>
  27 #include <linux/olpc-ec.h>
  28 #include <asm/tsc.h>
  29 #include <asm/olpc.h>
  30
  31 #include "olpc_dcon.h"
  32
  33 /* Module definitions */
  34
  35 static ushort resumeline = 898;
  36 module_param(resumeline, ushort, 0444);
  37
  38 static struct dcon_platform_data *pdata;
  39
  40 /* I2C structures */
  41
  42 /* Platform devices */
  43 static struct platform_device *dcon_device;
  44
  45 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
  46
  47 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
  48 {
  49         return i2c_smbus_write_word_data(dcon->client, reg, val);
  50 }
  51
  52 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
  53 {
  54         return i2c_smbus_read_word_data(dcon->client, reg);
  55 }
  56
  57 /* ===== API functions - these are called by a variety of users ==== */
  58
  59 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
  60 {
  61         u16 ver;
  62         int rc = 0;
  63
  64         ver = dcon_read(dcon, DCON_REG_ID);
  65         if ((ver >> 8) != 0xDC) {
  66                 pr_err("DCON ID not 0xDCxx: 0x%04x instead.\n", ver);
  67                 rc = -ENXIO;
  68                 goto err;
  69         }
  70
  71         if (is_init) {
  72                 pr_info("Discovered DCON version %x\n", ver & 0xFF);
  73                 rc = pdata->init(dcon);
  74                 if (rc != 0) {
  75                         pr_err("Unable to init.\n");
  76                         goto err;
  77                 }
  78         }
  79
  80         if (ver < 0xdc02) {
  81                 dev_err(&dcon->client->dev,
  82                         "DCON v1 is unsupported, giving up..\n");
  83                 rc = -ENODEV;
  84                 goto err;
  85         }
  86
  87         /* SDRAM setup/hold time */
  88         dcon_write(dcon, 0x3a, 0xc040);
  89         dcon_write(dcon, DCON_REG_MEM_OPT_A, 0x0000);  /* clear option bits */
  90         dcon_write(dcon, DCON_REG_MEM_OPT_A,
  91                    MEM_DLL_CLOCK_DELAY | MEM_POWER_DOWN);
  92         dcon_write(dcon, DCON_REG_MEM_OPT_B, MEM_SOFT_RESET);
  93
  94         /* Colour swizzle, AA, no passthrough, backlight */
  95         if (is_init) {
  96                 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
  97                                 MODE_CSWIZZLE | MODE_COL_AA;
  98         }
  99         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 100
 101         /* Set the scanline to interrupt on during resume */
 102         dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
 103
 104 err:
 105         return rc;
 106 }
 107
 108 /*
 109  * The smbus doesn't always come back due to what is believed to be
 110  * hardware (power rail) bugs.  For older models where this is known to
 111  * occur, our solution is to attempt to wait for the bus to stabilize;
 112  * if it doesn't happen, cut power to the dcon, repower it, and wait
 113  * for the bus to stabilize.  Rinse, repeat until we have a working
 114  * smbus.  For newer models, we simply BUG(); we want to know if this
 115  * still happens despite the power fixes that have been made!
 116  */
 117 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
 118 {
 119         unsigned long timeout;
 120         u8 pm;
 121         int x;
 122
 123 power_up:
 124         if (is_powered_down) {
 125                 pm = 1;
 126                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
 127                 if (x) {
 128                         pr_warn("unable to force dcon to power up: %d!\n", x);
 129                         return x;
 130                 }
 131                 usleep_range(10000, 11000);  /* we'll be conservative */
 132         }
 133
 134         pdata->bus_stabilize_wiggle();
 135
 136         for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
 137                 usleep_range(1000, 1100);
 138                 x = dcon_read(dcon, DCON_REG_ID);
 139         }
 140         if (x < 0) {
 141                 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
 142                 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
 143                 pm = 0;
 144                 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
 145                 msleep(100);
 146                 is_powered_down = 1;
 147                 goto power_up;  /* argh, stupid hardware.. */
 148         }
 149
 150         if (is_powered_down)
 151                 return dcon_hw_init(dcon, 0);
 152         return 0;
 153 }
 154
 155 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
 156 {
 157         dcon->bl_val = level;
 158         dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
 159
 160         /* Purposely turn off the backlight when we go to level 0 */
 161         if (dcon->bl_val == 0) {
 162                 dcon->disp_mode &= ~MODE_BL_ENABLE;
 163                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 164         } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
 165                 dcon->disp_mode |= MODE_BL_ENABLE;
 166                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 167         }
 168 }
 169
 170 /* Set the output type to either color or mono */
 171 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
 172 {
 173         if (dcon->mono == enable_mono)
 174                 return 0;
 175
 176         dcon->mono = enable_mono;
 177
 178         if (enable_mono) {
 179                 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
 180                 dcon->disp_mode |= MODE_MONO_LUMA;
 181         } else {
 182                 dcon->disp_mode &= ~(MODE_MONO_LUMA);
 183                 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
 184         }
 185
 186         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 187         return 0;
 188 }
 189
 190 /* For now, this will be really stupid - we need to address how
 191  * DCONLOAD works in a sleep and account for it accordingly
 192  */
 193
 194 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
 195 {
 196         int x;
 197
 198         /* Turn off the backlight and put the DCON to sleep */
 199
 200         if (dcon->asleep == sleep)
 201                 return;
 202
 203         if (!olpc_board_at_least(olpc_board(0xc2)))
 204                 return;
 205
 206         if (sleep) {
 207                 u8 pm = 0;
 208
 209                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
 210                 if (x)
 211                         pr_warn("unable to force dcon to power down: %d!\n", x);
 212                 else
 213                         dcon->asleep = sleep;
 214         } else {
 215                 /* Only re-enable the backlight if the backlight value is set */
 216                 if (dcon->bl_val != 0)
 217                         dcon->disp_mode |= MODE_BL_ENABLE;
 218                 x = dcon_bus_stabilize(dcon, 1);
 219                 if (x)
 220                         pr_warn("unable to reinit dcon hardware: %d!\n", x);
 221                 else
 222                         dcon->asleep = sleep;
 223
 224                 /* Restore backlight */
 225                 dcon_set_backlight(dcon, dcon->bl_val);
 226         }
 227
 228         /* We should turn off some stuff in the framebuffer - but what? */
 229 }
 230
 231 /* the DCON seems to get confused if we change DCONLOAD too
 232  * frequently -- i.e., approximately faster than frame time.
 233  * normally we don't change it this fast, so in general we won't
 234  * delay here.
 235  */
 236 static void dcon_load_holdoff(struct dcon_priv *dcon)
 237 {
 238         ktime_t delta_t, now;
 239
 240         while (1) {
 241                 now = ktime_get();
 242                 delta_t = ktime_sub(now, dcon->load_time);
 243                 if (ktime_to_ns(delta_t) > NSEC_PER_MSEC * 20)
 244                         break;
 245                 mdelay(4);
 246         }
 247 }
 248
 249 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
 250 {
 251         int err;
 252
 253         console_lock();
 254         lock_fb_info(dcon->fbinfo);
 255
 256         dcon->ignore_fb_events = true;
 257         err = fb_blank(dcon->fbinfo,
 258                        blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
 259         dcon->ignore_fb_events = false;
 260         unlock_fb_info(dcon->fbinfo);
 261         console_unlock();
 262
 263         if (err) {
 264                 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
 265                         blank ? "" : "un");
 266                 return false;
 267         }
 268         return true;
 269 }
 270
 271 /* Set the source of the display (CPU or DCON) */
 272 static void dcon_source_switch(struct work_struct *work)
 273 {
 274         struct dcon_priv *dcon = container_of(work, struct dcon_priv,
 275                         switch_source);
 276         int source = dcon->pending_src;
 277
 278         if (dcon->curr_src == source)
 279                 return;
 280
 281         dcon_load_holdoff(dcon);
 282
 283         dcon->switched = false;
 284
 285         switch (source) {
 286         case DCON_SOURCE_CPU:
 287                 pr_info("%s to CPU\n", __func__);
 288                 /* Enable the scanline interrupt bit */
 289                 if (dcon_write(dcon, DCON_REG_MODE,
 290                                dcon->disp_mode | MODE_SCAN_INT))
 291                         pr_err("couldn't enable scanline interrupt!\n");
 292                 else
 293                         /* Wait up to one second for the scanline interrupt */
 294                         wait_event_timeout(dcon->waitq, dcon->switched, HZ);
 295
 296                 if (!dcon->switched)
 297                         pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
 298
 299                 /* Turn off the scanline interrupt */
 300                 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
 301                         pr_err("couldn't disable scanline interrupt!\n");
 302
 303                 /*
 304                  * Ideally we'd like to disable interrupts here so that the
 305                  * fb unblanking and DCON turn on happen at a known time value;
 306                  * however, we can't do that right now with fb_blank
 307                  * messing with semaphores.
 308                  *
 309                  * For now, we just hope..
 310                  */
 311                 if (!dcon_blank_fb(dcon, false)) {
 312                         pr_err("Failed to enter CPU mode\n");
 313                         dcon->pending_src = DCON_SOURCE_DCON;
 314                         return;
 315                 }
 316
 317                 /* And turn off the DCON */
 318                 pdata->set_dconload(1);
 319                 dcon->load_time = ktime_get();
 320
 321                 pr_info("The CPU has control\n");
 322                 break;
 323         case DCON_SOURCE_DCON:
 324         {
 325                 ktime_t delta_t;
 326
 327                 pr_info("%s to DCON\n", __func__);
 328
 329                 /* Clear DCONLOAD - this implies that the DCON is in control */
 330                 pdata->set_dconload(0);
 331                 dcon->load_time = ktime_get();
 332
 333                 wait_event_timeout(dcon->waitq, dcon->switched, HZ / 2);
 334
 335                 if (!dcon->switched) {
 336                         pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
 337                 } else {
 338                         /* sometimes the DCON doesn't follow its own rules,
 339                          * and doesn't wait for two vsync pulses before
 340                          * ack'ing the frame load with an IRQ.  the result
 341                          * is that the display shows the *previously*
 342                          * loaded frame.  we can detect this by looking at
 343                          * the time between asserting DCONLOAD and the IRQ --
 344                          * if it's less than 20msec, then the DCON couldn't
 345                          * have seen two VSYNC pulses.  in that case we
 346                          * deassert and reassert, and hope for the best.
 347                          * see http://dev.laptop.org/ticket/9664
 348                          */
 349                         delta_t = ktime_sub(dcon->irq_time, dcon->load_time);
 350                         if (dcon->switched && ktime_to_ns(delta_t)
 351                             < NSEC_PER_MSEC * 20) {
 352                                 pr_err("missed loading, retrying\n");
 353                                 pdata->set_dconload(1);
 354                                 mdelay(41);
 355                                 pdata->set_dconload(0);
 356                                 dcon->load_time = ktime_get();
 357                                 mdelay(41);
 358                         }
 359                 }
 360
 361                 dcon_blank_fb(dcon, true);
 362                 pr_info("The DCON has control\n");
 363                 break;
 364         }
 365         default:
 366                 BUG();
 367         }
 368
 369         dcon->curr_src = source;
 370 }
 371
 372 static void dcon_set_source(struct dcon_priv *dcon, int arg)
 373 {
 374         if (dcon->pending_src == arg)
 375                 return;
 376
 377         dcon->pending_src = arg;
 378
 379         if (dcon->curr_src != arg)
 380                 schedule_work(&dcon->switch_source);
 381 }
 382
 383 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
 384 {
 385         dcon_set_source(dcon, arg);
 386         flush_scheduled_work();
 387 }
 388
 389 static ssize_t dcon_mode_show(struct device *dev,
 390                               struct device_attribute *attr,
 391                               char *buf)
 392 {
 393         struct dcon_priv *dcon = dev_get_drvdata(dev);
 394
 395         return sprintf(buf, "%4.4X\n", dcon->disp_mode);
 396 }
 397
 398 static ssize_t dcon_sleep_show(struct device *dev,
 399                                struct device_attribute *attr,
 400                                char *buf)
 401 {
 402         struct dcon_priv *dcon = dev_get_drvdata(dev);
 403
 404         return sprintf(buf, "%d\n", dcon->asleep);
 405 }
 406
 407 static ssize_t dcon_freeze_show(struct device *dev,
 408                                 struct device_attribute *attr,
 409                                 char *buf)
 410 {
 411         struct dcon_priv *dcon = dev_get_drvdata(dev);
 412
 413         return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
 414 }
 415
 416 static ssize_t dcon_mono_show(struct device *dev,
 417                               struct device_attribute *attr,
 418                               char *buf)
 419 {
 420         struct dcon_priv *dcon = dev_get_drvdata(dev);
 421
 422         return sprintf(buf, "%d\n", dcon->mono);
 423 }
 424
 425 static ssize_t dcon_resumeline_show(struct device *dev,
 426                                     struct device_attribute *attr,
 427                                     char *buf)
 428 {
 429         return sprintf(buf, "%d\n", resumeline);
 430 }
 431
 432 static ssize_t dcon_mono_store(struct device *dev,
 433                                struct device_attribute *attr,
 434                                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,
 450                                  const char *buf, size_t count)
 451 {
 452         struct dcon_priv *dcon = dev_get_drvdata(dev);
 453         unsigned long output;
 454         int ret;
 455
 456         ret = kstrtoul(buf, 10, &output);
 457         if (ret)
 458                 return ret;
 459
 460         switch (output) {
 461         case 0:
 462                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 463                 break;
 464         case 1:
 465                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 466                 break;
 467         case 2:  /* normally unused */
 468                 dcon_set_source(dcon, DCON_SOURCE_DCON);
 469                 break;
 470         default:
 471                 return -EINVAL;
 472         }
 473
 474         return count;
 475 }
 476
 477 static ssize_t dcon_resumeline_store(struct device *dev,
 478                                      struct device_attribute *attr,
 479                                      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,
 496                                 const char *buf, size_t count)
 497 {
 498         unsigned long output;
 499         int ret;
 500
 501         ret = kstrtoul(buf, 10, &output);
 502         if (ret)
 503                 return ret;
 504
 505         dcon_sleep(dev_get_drvdata(dev), output ? true : false);
 506         return count;
 507 }
 508
 509 static struct device_attribute dcon_device_files[] = {
 510         __ATTR(mode, 0444, dcon_mode_show, NULL),
 511         __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
 512         __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
 513         __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
 514         __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
 515 };
 516
 517 static int dcon_bl_update(struct backlight_device *dev)
 518 {
 519         struct dcon_priv *dcon = bl_get_data(dev);
 520         u8 level = dev->props.brightness & 0x0F;
 521
 522         if (dev->props.power != FB_BLANK_UNBLANK)
 523                 level = 0;
 524
 525         if (level != dcon->bl_val)
 526                 dcon_set_backlight(dcon, level);
 527
 528         /* power down the DCON when the screen is blanked */
 529         if (!dcon->ignore_fb_events)
 530                 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
 531
 532         return 0;
 533 }
 534
 535 static int dcon_bl_get(struct backlight_device *dev)
 536 {
 537         struct dcon_priv *dcon = bl_get_data(dev);
 538
 539         return dcon->bl_val;
 540 }
 541
 542 static const struct backlight_ops dcon_bl_ops = {
 543         .update_status = dcon_bl_update,
 544         .get_brightness = dcon_bl_get,
 545 };
 546
 547 static struct backlight_properties dcon_bl_props = {
 548         .max_brightness = 15,
 549         .type = BACKLIGHT_RAW,
 550         .power = FB_BLANK_UNBLANK,
 551 };
 552
 553 static int dcon_reboot_notify(struct notifier_block *nb,
 554                               unsigned long foo, void *bar)
 555 {
 556         struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
 557
 558         if (!dcon || !dcon->client)
 559                 return NOTIFY_DONE;
 560
 561         /* Turn off the DCON. Entirely. */
 562         dcon_write(dcon, DCON_REG_MODE, 0x39);
 563         dcon_write(dcon, DCON_REG_MODE, 0x32);
 564         return NOTIFY_DONE;
 565 }
 566
 567 static int unfreeze_on_panic(struct notifier_block *nb,
 568                              unsigned long e, void *p)
 569 {
 570         pdata->set_dconload(1);
 571         return NOTIFY_DONE;
 572 }
 573
 574 static struct notifier_block dcon_panic_nb = {
 575         .notifier_call = unfreeze_on_panic,
 576 };
 577
 578 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
 579 {
 580         strscpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
 581
 582         return 0;
 583 }
 584
 585 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
 586 {
 587         struct dcon_priv *dcon;
 588         int rc, i, j;
 589
 590         if (!pdata)
 591                 return -ENXIO;
 592
 593         dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
 594         if (!dcon)
 595                 return -ENOMEM;
 596
 597         dcon->client = client;
 598         init_waitqueue_head(&dcon->waitq);
 599         INIT_WORK(&dcon->switch_source, dcon_source_switch);
 600         dcon->reboot_nb.notifier_call = dcon_reboot_notify;
 601         dcon->reboot_nb.priority = -1;
 602
 603         i2c_set_clientdata(client, dcon);
 604
 605         if (num_registered_fb < 1) {
 606                 dev_err(&client->dev, "DCON driver requires a registered fb\n");
 607                 rc = -EIO;
 608                 goto einit;
 609         }
 610         dcon->fbinfo = registered_fb[0];
 611
 612         rc = dcon_hw_init(dcon, 1);
 613         if (rc)
 614                 goto einit;
 615
 616         /* Add the DCON device */
 617
 618         dcon_device = platform_device_alloc("dcon", -1);
 619
 620         if (!dcon_device) {
 621                 pr_err("Unable to create the DCON device\n");
 622                 rc = -ENOMEM;
 623                 goto eirq;
 624         }
 625         rc = platform_device_add(dcon_device);
 626         platform_set_drvdata(dcon_device, dcon);
 627
 628         if (rc) {
 629                 pr_err("Unable to add the DCON device\n");
 630                 goto edev;
 631         }
 632
 633         for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
 634                 rc = device_create_file(&dcon_device->dev,
 635                                         &dcon_device_files[i]);
 636                 if (rc) {
 637                         dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
 638                         goto ecreate;
 639                 }
 640         }
 641
 642         dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
 643
 644         /* Add the backlight device for the DCON */
 645         dcon_bl_props.brightness = dcon->bl_val;
 646         dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
 647                                                  dcon, &dcon_bl_ops,
 648                                                  &dcon_bl_props);
 649         if (IS_ERR(dcon->bl_dev)) {
 650                 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
 651                         PTR_ERR(dcon->bl_dev));
 652                 dcon->bl_dev = NULL;
 653         }
 654
 655         register_reboot_notifier(&dcon->reboot_nb);
 656         atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
 657
 658         return 0;
 659
 660  ecreate:
 661         for (j = 0; j < i; j++)
 662                 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
 663         platform_device_del(dcon_device);
 664  edev:
 665         platform_device_put(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)
 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 irqreturn_t dcon_interrupt(int irq, void *id)
 729 {
 730         struct dcon_priv *dcon = id;
 731         u8 status;
 732
 733         if (pdata->read_status(&status))
 734                 return IRQ_NONE;
 735
 736         switch (status & 3) {
 737         case 3:
 738                 pr_debug("DCONLOAD_MISSED interrupt\n");
 739                 break;
 740
 741         case 2: /* switch to DCON mode */
 742         case 1: /* switch to CPU mode */
 743                 dcon->switched = true;
 744                 dcon->irq_time = ktime_get();
 745                 wake_up(&dcon->waitq);
 746                 break;
 747
 748         case 0:
 749                 /* workaround resume case:  the DCON (on 1.5) doesn't
 750                  * ever assert status 0x01 when switching to CPU mode
 751                  * during resume.  this is because DCONLOAD is de-asserted
 752                  * _immediately_ upon exiting S3, so the actual release
 753                  * of the DCON happened long before this point.
 754                  * see http://dev.laptop.org/ticket/9869
 755                  */
 756                 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
 757                         dcon->switched = true;
 758                         dcon->irq_time = ktime_get();
 759                         wake_up(&dcon->waitq);
 760                         pr_debug("switching w/ status 0/0\n");
 761                 } else {
 762                         pr_debug("scanline interrupt w/CPU\n");
 763                 }
 764         }
 765
 766         return IRQ_HANDLED;
 767 }
 768
 769 static const struct dev_pm_ops dcon_pm_ops = {
 770         .suspend = dcon_suspend,
 771         .resume = dcon_resume,
 772 };
 773
 774 static const struct i2c_device_id dcon_idtable[] = {
 775         { "olpc_dcon",  0 },
 776         { }
 777 };
 778 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
 779
 780 static struct i2c_driver dcon_driver = {
 781         .driver = {
 782                 .name   = "olpc_dcon",
 783                 .pm = &dcon_pm_ops,
 784         },
 785         .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
 786         .id_table = dcon_idtable,
 787         .probe = dcon_probe,
 788         .remove = dcon_remove,
 789         .detect = dcon_detect,
 790         .address_list = normal_i2c,
 791 };
 792
 793 static int __init olpc_dcon_init(void)
 794 {
 795         /* XO-1.5 */
 796         if (olpc_board_at_least(olpc_board(0xd0)))
 797                 pdata = &dcon_pdata_xo_1_5;
 798         else
 799                 pdata = &dcon_pdata_xo_1;
 800
 801         return i2c_add_driver(&dcon_driver);
 802 }
 803
 804 static void __exit olpc_dcon_exit(void)
 805 {
 806         i2c_del_driver(&dcon_driver);
 807 }
 808
 809 module_init(olpc_dcon_init);
 810 module_exit(olpc_dcon_exit);
 811
 812 MODULE_LICENSE("GPL");