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, 0x41, 0x0000);
  94         dcon_write(dcon, 0x41, 0x0101);
  95         dcon_write(dcon, 0x42, 0x0101);
  96
  97         /* Colour swizzle, AA, no passthrough, backlight */
  98         if (is_init) {
  99                 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
 100                                 MODE_CSWIZZLE | MODE_COL_AA;
 101         }
 102         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 103
 104
 105         /* Set the scanline to interrupt on during resume */
 106         dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
 107
 108 err:
 109         return rc;
 110 }
 111
 112 /*
 113  * The smbus doesn't always come back due to what is believed to be
 114  * hardware (power rail) bugs.  For older models where this is known to
 115  * occur, our solution is to attempt to wait for the bus to stabilize;
 116  * if it doesn't happen, cut power to the dcon, repower it, and wait
 117  * for the bus to stabilize.  Rinse, repeat until we have a working
 118  * smbus.  For newer models, we simply BUG(); we want to know if this
 119  * still happens despite the power fixes that have been made!
 120  */
 121 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
 122 {
 123         unsigned long timeout;
 124         int x;
 125
 126 power_up:
 127         if (is_powered_down) {
 128                 x = 1;
 129                 x = olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL, 0);
 130                 if (x) {
 131                         pr_warn("unable to force dcon to power up: %d!\n", x);
 132                         return x;
 133                 }
 134                 msleep(10); /* we'll be conservative */
 135         }
 136
 137         pdata->bus_stabilize_wiggle();
 138
 139         for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
 140                 msleep(1);
 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                 x = 0;
 147                 olpc_ec_cmd(0x26, (unsigned char *)&x, 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                 x = 0;
 211                 x = olpc_ec_cmd(0x26, (unsigned char *)&x, 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         struct timespec delta_t, now;
 241         while (1) {
 242                 getnstimeofday(&now);
 243                 delta_t = timespec_sub(now, dcon->load_time);
 244                 if (delta_t.tv_sec != 0 ||
 245                         delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
 246                         break;
 247                 }
 248                 mdelay(4);
 249         }
 250 }
 251
 252 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
 253 {
 254         int err;
 255
 256         if (!lock_fb_info(dcon->fbinfo)) {
 257                 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
 258                 return false;
 259         }
 260         console_lock();
 261         dcon->ignore_fb_events = true;
 262         err = fb_blank(dcon->fbinfo,
 263                         blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
 264         dcon->ignore_fb_events = false;
 265         console_unlock();
 266         unlock_fb_info(dcon->fbinfo);
 267
 268         if (err) {
 269                 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
 270                                 blank ? "" : "un");
 271                 return false;
 272         }
 273         return true;
 274 }
 275
 276 /* Set the source of the display (CPU or DCON) */
 277 static void dcon_source_switch(struct work_struct *work)
 278 {
 279         struct dcon_priv *dcon = container_of(work, struct dcon_priv,
 280                         switch_source);
 281         int source = dcon->pending_src;
 282
 283         if (dcon->curr_src == source)
 284                 return;
 285
 286         dcon_load_holdoff(dcon);
 287
 288         dcon->switched = false;
 289
 290         switch (source) {
 291         case DCON_SOURCE_CPU:
 292                 pr_info("dcon_source_switch to CPU\n");
 293                 /* Enable the scanline interrupt bit */
 294                 if (dcon_write(dcon, DCON_REG_MODE,
 295                                 dcon->disp_mode | MODE_SCAN_INT))
 296                         pr_err("couldn't enable scanline interrupt!\n");
 297                 else
 298                         /* Wait up to one second for the scanline interrupt */
 299                         wait_event_timeout(dcon->waitq, dcon->switched, HZ);
 300
 301                 if (!dcon->switched)
 302                         pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
 303
 304                 /* Turn off the scanline interrupt */
 305                 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
 306                         pr_err("couldn't disable scanline interrupt!\n");
 307
 308                 /*
 309                  * Ideally we'd like to disable interrupts here so that the
 310                  * fb unblanking and DCON turn on happen at a known time value;
 311                  * however, we can't do that right now with fb_blank
 312                  * messing with semaphores.
 313                  *
 314                  * For now, we just hope..
 315                  */
 316                 if (!dcon_blank_fb(dcon, false)) {
 317                         pr_err("Failed to enter CPU mode\n");
 318                         dcon->pending_src = DCON_SOURCE_DCON;
 319                         return;
 320                 }
 321
 322                 /* And turn off the DCON */
 323                 pdata->set_dconload(1);
 324                 getnstimeofday(&dcon->load_time);
 325
 326                 pr_info("The CPU has control\n");
 327                 break;
 328         case DCON_SOURCE_DCON:
 329         {
 330                 struct timespec delta_t;
 331
 332                 pr_info("dcon_source_switch to DCON\n");
 333
 334                 /* Clear DCONLOAD - this implies that the DCON is in control */
 335                 pdata->set_dconload(0);
 336                 getnstimeofday(&dcon->load_time);
 337
 338                 wait_event_timeout(dcon->waitq, dcon->switched, HZ/2);
 339
 340                 if (!dcon->switched) {
 341                         pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
 342                 } else {
 343                         /* sometimes the DCON doesn't follow its own rules,
 344                          * and doesn't wait for two vsync pulses before
 345                          * ack'ing the frame load with an IRQ.  the result
 346                          * is that the display shows the *previously*
 347                          * loaded frame.  we can detect this by looking at
 348                          * the time between asserting DCONLOAD and the IRQ --
 349                          * if it's less than 20msec, then the DCON couldn't
 350                          * have seen two VSYNC pulses.  in that case we
 351                          * deassert and reassert, and hope for the best.
 352                          * see http://dev.laptop.org/ticket/9664
 353                          */
 354                         delta_t = timespec_sub(dcon->irq_time, dcon->load_time);
 355                         if (dcon->switched && delta_t.tv_sec == 0 &&
 356                                         delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
 357                                 pr_err("missed loading, retrying\n");
 358                                 pdata->set_dconload(1);
 359                                 mdelay(41);
 360                                 pdata->set_dconload(0);
 361                                 getnstimeofday(&dcon->load_time);
 362                                 mdelay(41);
 363                         }
 364                 }
 365
 366                 dcon_blank_fb(dcon, true);
 367                 pr_info("The DCON has control\n");
 368                 break;
 369         }
 370         default:
 371                 BUG();
 372         }
 373
 374         dcon->curr_src = source;
 375 }
 376
 377 static void dcon_set_source(struct dcon_priv *dcon, int arg)
 378 {
 379         if (dcon->pending_src == arg)
 380                 return;
 381
 382         dcon->pending_src = arg;
 383
 384         if ((dcon->curr_src != arg) && !work_pending(&dcon->switch_source))
 385                 schedule_work(&dcon->switch_source);
 386 }
 387
 388 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
 389 {
 390         dcon_set_source(dcon, arg);
 391         flush_scheduled_work();
 392 }
 393
 394 static ssize_t dcon_mode_show(struct device *dev,
 395         struct device_attribute *attr, char *buf)
 396 {
 397         struct dcon_priv *dcon = dev_get_drvdata(dev);
 398         return sprintf(buf, "%4.4X\n", dcon->disp_mode);
 399 }
 400
 401 static ssize_t dcon_sleep_show(struct device *dev,
 402         struct device_attribute *attr, char *buf)
 403 {
 404
 405         struct dcon_priv *dcon = dev_get_drvdata(dev);
 406         return sprintf(buf, "%d\n", dcon->asleep);
 407 }
 408
 409 static ssize_t dcon_freeze_show(struct device *dev,
 410         struct device_attribute *attr, char *buf)
 411 {
 412         struct dcon_priv *dcon = dev_get_drvdata(dev);
 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, char *buf)
 418 {
 419         struct dcon_priv *dcon = dev_get_drvdata(dev);
 420         return sprintf(buf, "%d\n", dcon->mono);
 421 }
 422
 423 static ssize_t dcon_resumeline_show(struct device *dev,
 424         struct device_attribute *attr, char *buf)
 425 {
 426         return sprintf(buf, "%d\n", resumeline);
 427 }
 428
 429 static ssize_t dcon_mono_store(struct device *dev,
 430         struct device_attribute *attr, const char *buf, size_t count)
 431 {
 432         unsigned long enable_mono;
 433         int rc;
 434
 435         rc = kstrtoul(buf, 10, &enable_mono);
 436         if (rc)
 437                 return rc;
 438
 439         dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
 440
 441         return count;
 442 }
 443
 444 static ssize_t dcon_freeze_store(struct device *dev,
 445         struct device_attribute *attr, const char *buf, size_t count)
 446 {
 447         struct dcon_priv *dcon = dev_get_drvdata(dev);
 448         unsigned long output;
 449         int ret;
 450
 451         ret = kstrtoul(buf, 10, &output);
 452         if (ret)
 453                 return ret;
 454
 455         pr_info("dcon_freeze_store: %lu\n", output);
 456
 457         switch (output) {
 458         case 0:
 459                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 460                 break;
 461         case 1:
 462                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 463                 break;
 464         case 2:  /* normally unused */
 465                 dcon_set_source(dcon, DCON_SOURCE_DCON);
 466                 break;
 467         default:
 468                 return -EINVAL;
 469         }
 470
 471         return count;
 472 }
 473
 474 static ssize_t dcon_resumeline_store(struct device *dev,
 475         struct device_attribute *attr, const char *buf, size_t count)
 476 {
 477         unsigned short rl;
 478         int rc;
 479
 480         rc = kstrtou16(buf, 10, &rl);
 481         if (rc)
 482                 return rc;
 483
 484         resumeline = rl;
 485         dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
 486
 487         return count;
 488 }
 489
 490 static ssize_t dcon_sleep_store(struct device *dev,
 491         struct device_attribute *attr, const char *buf, size_t count)
 492 {
 493         unsigned long output;
 494         int ret;
 495
 496         ret = kstrtoul(buf, 10, &output);
 497         if (ret)
 498                 return ret;
 499
 500         dcon_sleep(dev_get_drvdata(dev), output ? true : false);
 501         return count;
 502 }
 503
 504 static struct device_attribute dcon_device_files[] = {
 505         __ATTR(mode, 0444, dcon_mode_show, NULL),
 506         __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
 507         __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
 508         __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
 509         __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
 510 };
 511
 512 static int dcon_bl_update(struct backlight_device *dev)
 513 {
 514         struct dcon_priv *dcon = bl_get_data(dev);
 515         u8 level = dev->props.brightness & 0x0F;
 516
 517         if (dev->props.power != FB_BLANK_UNBLANK)
 518                 level = 0;
 519
 520         if (level != dcon->bl_val)
 521                 dcon_set_backlight(dcon, level);
 522
 523         /* power down the DCON when the screen is blanked */
 524         if (!dcon->ignore_fb_events)
 525                 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
 526
 527         return 0;
 528 }
 529
 530 static int dcon_bl_get(struct backlight_device *dev)
 531 {
 532         struct dcon_priv *dcon = bl_get_data(dev);
 533         return dcon->bl_val;
 534 }
 535
 536 static const struct backlight_ops dcon_bl_ops = {
 537         .update_status = dcon_bl_update,
 538         .get_brightness = dcon_bl_get,
 539 };
 540
 541 static struct backlight_properties dcon_bl_props = {
 542         .max_brightness = 15,
 543         .type = BACKLIGHT_RAW,
 544         .power = FB_BLANK_UNBLANK,
 545 };
 546
 547 static int dcon_reboot_notify(struct notifier_block *nb,
 548                               unsigned long foo, void *bar)
 549 {
 550         struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
 551
 552         if (!dcon || !dcon->client)
 553                 return 0;
 554
 555         /* Turn off the DCON. Entirely. */
 556         dcon_write(dcon, DCON_REG_MODE, 0x39);
 557         dcon_write(dcon, DCON_REG_MODE, 0x32);
 558         return 0;
 559 }
 560
 561 static int unfreeze_on_panic(struct notifier_block *nb,
 562                              unsigned long e, void *p)
 563 {
 564         pdata->set_dconload(1);
 565         return NOTIFY_DONE;
 566 }
 567
 568 static struct notifier_block dcon_panic_nb = {
 569         .notifier_call = unfreeze_on_panic,
 570 };
 571
 572 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
 573 {
 574         strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
 575
 576         return 0;
 577 }
 578
 579 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
 580 {
 581         struct dcon_priv *dcon;
 582         int rc, i, j;
 583
 584         if (!pdata)
 585                 return -ENXIO;
 586
 587         dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
 588         if (!dcon)
 589                 return -ENOMEM;
 590
 591         dcon->client = client;
 592         init_waitqueue_head(&dcon->waitq);
 593         INIT_WORK(&dcon->switch_source, dcon_source_switch);
 594         dcon->reboot_nb.notifier_call = dcon_reboot_notify;
 595         dcon->reboot_nb.priority = -1;
 596
 597         i2c_set_clientdata(client, dcon);
 598
 599         if (num_registered_fb < 1) {
 600                 dev_err(&client->dev, "DCON driver requires a registered fb\n");
 601                 rc = -EIO;
 602                 goto einit;
 603         }
 604         dcon->fbinfo = registered_fb[0];
 605
 606         rc = dcon_hw_init(dcon, 1);
 607         if (rc)
 608                 goto einit;
 609
 610         /* Add the DCON device */
 611
 612         dcon_device = platform_device_alloc("dcon", -1);
 613
 614         if (dcon_device == NULL) {
 615                 pr_err("Unable to create the DCON device\n");
 616                 rc = -ENOMEM;
 617                 goto eirq;
 618         }
 619         rc = platform_device_add(dcon_device);
 620         platform_set_drvdata(dcon_device, dcon);
 621
 622         if (rc) {
 623                 pr_err("Unable to add the DCON device\n");
 624                 goto edev;
 625         }
 626
 627         for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
 628                 rc = device_create_file(&dcon_device->dev,
 629                                         &dcon_device_files[i]);
 630                 if (rc) {
 631                         dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
 632                         goto ecreate;
 633                 }
 634         }
 635
 636         dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
 637
 638         /* Add the backlight device for the DCON */
 639         dcon_bl_props.brightness = dcon->bl_val;
 640         dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
 641                 dcon, &dcon_bl_ops, &dcon_bl_props);
 642         if (IS_ERR(dcon->bl_dev)) {
 643                 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
 644                                 PTR_ERR(dcon->bl_dev));
 645                 dcon->bl_dev = NULL;
 646         }
 647
 648         register_reboot_notifier(&dcon->reboot_nb);
 649         atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
 650
 651         return 0;
 652
 653  ecreate:
 654         for (j = 0; j < i; j++)
 655                 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
 656  edev:
 657         platform_device_unregister(dcon_device);
 658         dcon_device = NULL;
 659  eirq:
 660         free_irq(DCON_IRQ, dcon);
 661  einit:
 662         kfree(dcon);
 663         return rc;
 664 }
 665
 666 static int dcon_remove(struct i2c_client *client)
 667 {
 668         struct dcon_priv *dcon = i2c_get_clientdata(client);
 669
 670         unregister_reboot_notifier(&dcon->reboot_nb);
 671         atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
 672
 673         free_irq(DCON_IRQ, dcon);
 674
 675         if (dcon->bl_dev)
 676                 backlight_device_unregister(dcon->bl_dev);
 677
 678         if (dcon_device != NULL)
 679                 platform_device_unregister(dcon_device);
 680         cancel_work_sync(&dcon->switch_source);
 681
 682         kfree(dcon);
 683
 684         return 0;
 685 }
 686
 687 #ifdef CONFIG_PM
 688 static int dcon_suspend(struct device *dev)
 689 {
 690         struct i2c_client *client = to_i2c_client(dev);
 691         struct dcon_priv *dcon = i2c_get_clientdata(client);
 692
 693         if (!dcon->asleep) {
 694                 /* Set up the DCON to have the source */
 695                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 696         }
 697
 698         return 0;
 699 }
 700
 701 static int dcon_resume(struct device *dev)
 702 {
 703         struct i2c_client *client = to_i2c_client(dev);
 704         struct dcon_priv *dcon = i2c_get_clientdata(client);
 705
 706         if (!dcon->asleep) {
 707                 dcon_bus_stabilize(dcon, 0);
 708                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 709         }
 710
 711         return 0;
 712 }
 713
 714 #else
 715
 716 #define dcon_suspend NULL
 717 #define dcon_resume NULL
 718
 719 #endif /* CONFIG_PM */
 720
 721
 722 irqreturn_t dcon_interrupt(int irq, void *id)
 723 {
 724         struct dcon_priv *dcon = id;
 725         u8 status;
 726
 727         if (pdata->read_status(&status))
 728                 return IRQ_NONE;
 729
 730         switch (status & 3) {
 731         case 3:
 732                 pr_debug("DCONLOAD_MISSED interrupt\n");
 733                 break;
 734
 735         case 2: /* switch to DCON mode */
 736         case 1: /* switch to CPU mode */
 737                 dcon->switched = true;
 738                 getnstimeofday(&dcon->irq_time);
 739                 wake_up(&dcon->waitq);
 740                 break;
 741
 742         case 0:
 743                 /* workaround resume case:  the DCON (on 1.5) doesn't
 744                  * ever assert status 0x01 when switching to CPU mode
 745                  * during resume.  this is because DCONLOAD is de-asserted
 746                  * _immediately_ upon exiting S3, so the actual release
 747                  * of the DCON happened long before this point.
 748                  * see http://dev.laptop.org/ticket/9869
 749                  */
 750                 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
 751                         dcon->switched = true;
 752                         getnstimeofday(&dcon->irq_time);
 753                         wake_up(&dcon->waitq);
 754                         pr_debug("switching w/ status 0/0\n");
 755                 } else {
 756                         pr_debug("scanline interrupt w/CPU\n");
 757                 }
 758         }
 759
 760         return IRQ_HANDLED;
 761 }
 762
 763 static const struct dev_pm_ops dcon_pm_ops = {
 764         .suspend = dcon_suspend,
 765         .resume = dcon_resume,
 766 };
 767
 768 static const struct i2c_device_id dcon_idtable[] = {
 769         { "olpc_dcon",  0 },
 770         { }
 771 };
 772 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
 773
 774 struct i2c_driver dcon_driver = {
 775         .driver = {
 776                 .name   = "olpc_dcon",
 777                 .pm = &dcon_pm_ops,
 778         },
 779         .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
 780         .id_table = dcon_idtable,
 781         .probe = dcon_probe,
 782         .remove = dcon_remove,
 783         .detect = dcon_detect,
 784         .address_list = normal_i2c,
 785 };
 786
 787 static int __init olpc_dcon_init(void)
 788 {
 789 #ifdef CONFIG_FB_OLPC_DCON_1_5
 790         /* XO-1.5 */
 791         if (olpc_board_at_least(olpc_board(0xd0)))
 792                 pdata = &dcon_pdata_xo_1_5;
 793 #endif
 794 #ifdef CONFIG_FB_OLPC_DCON_1
 795         if (!pdata)
 796                 pdata = &dcon_pdata_xo_1;
 797 #endif
 798
 799         return i2c_add_driver(&dcon_driver);
 800 }
 801
 802 static void __exit olpc_dcon_exit(void)
 803 {
 804         i2c_del_driver(&dcon_driver);
 805 }
 806
 807 module_init(olpc_dcon_init);
 808 module_exit(olpc_dcon_exit);
 809
 810 MODULE_LICENSE("GPL");