drivers/hid/hid-picolcd_fb.c

   1 /***************************************************************************
   2  *   Copyright (C) 2010-2012 by Bruno Prémont <bonbons@linux-vserver.org>  *
   3  *                                                                         *
   4  *   Based on Logitech G13 driver (v0.4)                                   *
   5  *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard@cs.nmsu.edu>   *
   6  *                                                                         *
   7  *   This program is free software: you can redistribute it and/or modify  *
   8  *   it under the terms of the GNU General Public License as published by  *
   9  *   the Free Software Foundation, version 2 of the License.               *
  10  *                                                                         *
  11  *   This driver is distributed in the hope that it will be useful, but    *
  12  *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
  14  *   General Public License for more details.                              *
  15  *                                                                         *
  16  *   You should have received a copy of the GNU General Public License     *
  17  *   along with this software. If not see <http://www.gnu.org/licenses/>.  *
  18  ***************************************************************************/
  19
  20 #include <linux/hid.h>
  21 #include <linux/vmalloc.h>
  22
  23 #include <linux/fb.h>
  24 #include <linux/module.h>
  25
  26 #include "hid-picolcd.h"
  27
  28 /* Framebuffer
  29  *
  30  * The PicoLCD use a Topway LCD module of 256x64 pixel
  31  * This display area is tiled over 4 controllers with 8 tiles
  32  * each. Each tile has 8x64 pixel, each data byte representing
  33  * a 1-bit wide vertical line of the tile.
  34  *
  35  * The display can be updated at a tile granularity.
  36  *
  37  *       Chip 1           Chip 2           Chip 3           Chip 4
  38  * +----------------+----------------+----------------+----------------+
  39  * |     Tile 1     |     Tile 1     |     Tile 1     |     Tile 1     |
  40  * +----------------+----------------+----------------+----------------+
  41  * |     Tile 2     |     Tile 2     |     Tile 2     |     Tile 2     |
  42  * +----------------+----------------+----------------+----------------+
  43  *                                  ...
  44  * +----------------+----------------+----------------+----------------+
  45  * |     Tile 8     |     Tile 8     |     Tile 8     |     Tile 8     |
  46  * +----------------+----------------+----------------+----------------+
  47  */
  48 #define PICOLCDFB_NAME "picolcdfb"
  49 #define PICOLCDFB_WIDTH (256)
  50 #define PICOLCDFB_HEIGHT (64)
  51 #define PICOLCDFB_SIZE (PICOLCDFB_WIDTH * PICOLCDFB_HEIGHT / 8)
  52
  53 #define PICOLCDFB_UPDATE_RATE_LIMIT   10
  54 #define PICOLCDFB_UPDATE_RATE_DEFAULT  2
  55
  56 /* Framebuffer visual structures */
  57 static const struct fb_fix_screeninfo picolcdfb_fix = {
  58         .id          = PICOLCDFB_NAME,
  59         .type        = FB_TYPE_PACKED_PIXELS,
  60         .visual      = FB_VISUAL_MONO01,
  61         .xpanstep    = 0,
  62         .ypanstep    = 0,
  63         .ywrapstep   = 0,
  64         .line_length = PICOLCDFB_WIDTH / 8,
  65         .accel       = FB_ACCEL_NONE,
  66 };
  67
  68 static const struct fb_var_screeninfo picolcdfb_var = {
  69         .xres           = PICOLCDFB_WIDTH,
  70         .yres           = PICOLCDFB_HEIGHT,
  71         .xres_virtual   = PICOLCDFB_WIDTH,
  72         .yres_virtual   = PICOLCDFB_HEIGHT,
  73         .width          = 103,
  74         .height         = 26,
  75         .bits_per_pixel = 1,
  76         .grayscale      = 1,
  77         .red            = {
  78                 .offset = 0,
  79                 .length = 1,
  80                 .msb_right = 0,
  81         },
  82         .green          = {
  83                 .offset = 0,
  84                 .length = 1,
  85                 .msb_right = 0,
  86         },
  87         .blue           = {
  88                 .offset = 0,
  89                 .length = 1,
  90                 .msb_right = 0,
  91         },
  92         .transp         = {
  93                 .offset = 0,
  94                 .length = 0,
  95                 .msb_right = 0,
  96         },
  97 };
  98
  99 /* Send a given tile to PicoLCD */
 100 static int picolcd_fb_send_tile(struct picolcd_data *data, u8 *vbitmap,
 101                 int chip, int tile)
 102 {
 103         struct hid_report *report1, *report2;
 104         unsigned long flags;
 105         u8 *tdata;
 106         int i;
 107
 108         report1 = picolcd_out_report(REPORT_LCD_CMD_DATA, data->hdev);
 109         if (!report1 || report1->maxfield != 1)
 110                 return -ENODEV;
 111         report2 = picolcd_out_report(REPORT_LCD_DATA, data->hdev);
 112         if (!report2 || report2->maxfield != 1)
 113                 return -ENODEV;
 114
 115         spin_lock_irqsave(&data->lock, flags);
 116         if ((data->status & PICOLCD_FAILED)) {
 117                 spin_unlock_irqrestore(&data->lock, flags);
 118                 return -ENODEV;
 119         }
 120         hid_set_field(report1->field[0],  0, chip << 2);
 121         hid_set_field(report1->field[0],  1, 0x02);
 122         hid_set_field(report1->field[0],  2, 0x00);
 123         hid_set_field(report1->field[0],  3, 0x00);
 124         hid_set_field(report1->field[0],  4, 0xb8 | tile);
 125         hid_set_field(report1->field[0],  5, 0x00);
 126         hid_set_field(report1->field[0],  6, 0x00);
 127         hid_set_field(report1->field[0],  7, 0x40);
 128         hid_set_field(report1->field[0],  8, 0x00);
 129         hid_set_field(report1->field[0],  9, 0x00);
 130         hid_set_field(report1->field[0], 10,   32);
 131
 132         hid_set_field(report2->field[0],  0, (chip << 2) | 0x01);
 133         hid_set_field(report2->field[0],  1, 0x00);
 134         hid_set_field(report2->field[0],  2, 0x00);
 135         hid_set_field(report2->field[0],  3,   32);
 136
 137         tdata = vbitmap + (tile * 4 + chip) * 64;
 138         for (i = 0; i < 64; i++)
 139                 if (i < 32)
 140                         hid_set_field(report1->field[0], 11 + i, tdata[i]);
 141                 else
 142                         hid_set_field(report2->field[0], 4 + i - 32, tdata[i]);
 143
 144         hid_hw_request(data->hdev, report1, HID_REQ_SET_REPORT);
 145         hid_hw_request(data->hdev, report2, HID_REQ_SET_REPORT);
 146         spin_unlock_irqrestore(&data->lock, flags);
 147         return 0;
 148 }
 149
 150 /* Translate a single tile*/
 151 static int picolcd_fb_update_tile(u8 *vbitmap, const u8 *bitmap, int bpp,
 152                 int chip, int tile)
 153 {
 154         int i, b, changed = 0;
 155         u8 tdata[64];
 156         u8 *vdata = vbitmap + (tile * 4 + chip) * 64;
 157
 158         if (bpp == 1) {
 159                 for (b = 7; b >= 0; b--) {
 160                         const u8 *bdata = bitmap + tile * 256 + chip * 8 + b * 32;
 161                         for (i = 0; i < 64; i++) {
 162                                 tdata[i] <<= 1;
 163                                 tdata[i] |= (bdata[i/8] >> (i % 8)) & 0x01;
 164                         }
 165                 }
 166         } else if (bpp == 8) {
 167                 for (b = 7; b >= 0; b--) {
 168                         const u8 *bdata = bitmap + (tile * 256 + chip * 8 + b * 32) * 8;
 169                         for (i = 0; i < 64; i++) {
 170                                 tdata[i] <<= 1;
 171                                 tdata[i] |= (bdata[i] & 0x80) ? 0x01 : 0x00;
 172                         }
 173                 }
 174         } else {
 175                 /* Oops, we should never get here! */
 176                 WARN_ON(1);
 177                 return 0;
 178         }
 179
 180         for (i = 0; i < 64; i++)
 181                 if (tdata[i] != vdata[i]) {
 182                         changed = 1;
 183                         vdata[i] = tdata[i];
 184                 }
 185         return changed;
 186 }
 187
 188 void picolcd_fb_refresh(struct picolcd_data *data)
 189 {
 190         if (data->fb_info)
 191                 schedule_delayed_work(&data->fb_info->deferred_work, 0);
 192 }
 193
 194 /* Reconfigure LCD display */
 195 int picolcd_fb_reset(struct picolcd_data *data, int clear)
 196 {
 197         struct hid_report *report = picolcd_out_report(REPORT_LCD_CMD, data->hdev);
 198         struct picolcd_fb_data *fbdata = data->fb_info->par;
 199         int i, j;
 200         unsigned long flags;
 201         static const u8 mapcmd[8] = { 0x00, 0x02, 0x00, 0x64, 0x3f, 0x00, 0x64, 0xc0 };
 202
 203         if (!report || report->maxfield != 1)
 204                 return -ENODEV;
 205
 206         spin_lock_irqsave(&data->lock, flags);
 207         for (i = 0; i < 4; i++) {
 208                 for (j = 0; j < report->field[0]->maxusage; j++)
 209                         if (j == 0)
 210                                 hid_set_field(report->field[0], j, i << 2);
 211                         else if (j < sizeof(mapcmd))
 212                                 hid_set_field(report->field[0], j, mapcmd[j]);
 213                         else
 214                                 hid_set_field(report->field[0], j, 0);
 215                 hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
 216         }
 217         spin_unlock_irqrestore(&data->lock, flags);
 218
 219         if (clear) {
 220                 memset(fbdata->vbitmap, 0, PICOLCDFB_SIZE);
 221                 memset(fbdata->bitmap, 0, PICOLCDFB_SIZE*fbdata->bpp);
 222         }
 223         fbdata->force = 1;
 224
 225         /* schedule first output of framebuffer */
 226         if (fbdata->ready)
 227                 schedule_delayed_work(&data->fb_info->deferred_work, 0);
 228         else
 229                 fbdata->ready = 1;
 230
 231         return 0;
 232 }
 233
 234 /* Update fb_vbitmap from the screen_base and send changed tiles to device */
 235 static void picolcd_fb_update(struct fb_info *info)
 236 {
 237         int chip, tile, n;
 238         unsigned long flags;
 239         struct picolcd_fb_data *fbdata = info->par;
 240         struct picolcd_data *data;
 241
 242         mutex_lock(&info->lock);
 243
 244         spin_lock_irqsave(&fbdata->lock, flags);
 245         if (!fbdata->ready && fbdata->picolcd)
 246                 picolcd_fb_reset(fbdata->picolcd, 0);
 247         spin_unlock_irqrestore(&fbdata->lock, flags);
 248
 249         /*
 250          * Translate the framebuffer into the format needed by the PicoLCD.
 251          * See display layout above.
 252          * Do this one tile after the other and push those tiles that changed.
 253          *
 254          * Wait for our IO to complete as otherwise we might flood the queue!
 255          */
 256         n = 0;
 257         for (chip = 0; chip < 4; chip++)
 258                 for (tile = 0; tile < 8; tile++) {
 259                         if (!fbdata->force && !picolcd_fb_update_tile(
 260                                         fbdata->vbitmap, fbdata->bitmap,
 261                                         fbdata->bpp, chip, tile))
 262                                 continue;
 263                         n += 2;
 264                         if (n >= HID_OUTPUT_FIFO_SIZE / 2) {
 265                                 spin_lock_irqsave(&fbdata->lock, flags);
 266                                 data = fbdata->picolcd;
 267                                 spin_unlock_irqrestore(&fbdata->lock, flags);
 268                                 mutex_unlock(&info->lock);
 269                                 if (!data)
 270                                         return;
 271                                 hid_hw_wait(data->hdev);
 272                                 mutex_lock(&info->lock);
 273                                 n = 0;
 274                         }
 275                         spin_lock_irqsave(&fbdata->lock, flags);
 276                         data = fbdata->picolcd;
 277                         spin_unlock_irqrestore(&fbdata->lock, flags);
 278                         if (!data || picolcd_fb_send_tile(data,
 279                                         fbdata->vbitmap, chip, tile))
 280                                 goto out;
 281                 }
 282         fbdata->force = false;
 283         if (n) {
 284                 spin_lock_irqsave(&fbdata->lock, flags);
 285                 data = fbdata->picolcd;
 286                 spin_unlock_irqrestore(&fbdata->lock, flags);
 287                 mutex_unlock(&info->lock);
 288                 if (data)
 289                         hid_hw_wait(data->hdev);
 290                 return;
 291         }
 292 out:
 293         mutex_unlock(&info->lock);
 294 }
 295
 296 /* Stub to call the system default and update the image on the picoLCD */
 297 static void picolcd_fb_fillrect(struct fb_info *info,
 298                 const struct fb_fillrect *rect)
 299 {
 300         if (!info->par)
 301                 return;
 302         sys_fillrect(info, rect);
 303
 304         schedule_delayed_work(&info->deferred_work, 0);
 305 }
 306
 307 /* Stub to call the system default and update the image on the picoLCD */
 308 static void picolcd_fb_copyarea(struct fb_info *info,
 309                 const struct fb_copyarea *area)
 310 {
 311         if (!info->par)
 312                 return;
 313         sys_copyarea(info, area);
 314
 315         schedule_delayed_work(&info->deferred_work, 0);
 316 }
 317
 318 /* Stub to call the system default and update the image on the picoLCD */
 319 static void picolcd_fb_imageblit(struct fb_info *info, const struct fb_image *image)
 320 {
 321         if (!info->par)
 322                 return;
 323         sys_imageblit(info, image);
 324
 325         schedule_delayed_work(&info->deferred_work, 0);
 326 }
 327
 328 /*
 329  * this is the slow path from userspace. they can seek and write to
 330  * the fb. it's inefficient to do anything less than a full screen draw
 331  */
 332 static ssize_t picolcd_fb_write(struct fb_info *info, const char __user *buf,
 333                 size_t count, loff_t *ppos)
 334 {
 335         ssize_t ret;
 336         if (!info->par)
 337                 return -ENODEV;
 338         ret = fb_sys_write(info, buf, count, ppos);
 339         if (ret >= 0)
 340                 schedule_delayed_work(&info->deferred_work, 0);
 341         return ret;
 342 }
 343
 344 static int picolcd_fb_blank(int blank, struct fb_info *info)
 345 {
 346         /* We let fb notification do this for us via lcd/backlight device */
 347         return 0;
 348 }
 349
 350 static void picolcd_fb_destroy(struct fb_info *info)
 351 {
 352         struct picolcd_fb_data *fbdata = info->par;
 353
 354         /* make sure no work is deferred */
 355         fb_deferred_io_cleanup(info);
 356
 357         /* No thridparty should ever unregister our framebuffer! */
 358         WARN_ON(fbdata->picolcd != NULL);
 359
 360         vfree((u8 *)info->fix.smem_start);
 361         framebuffer_release(info);
 362 }
 363
 364 static int picolcd_fb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
 365 {
 366         __u32 bpp      = var->bits_per_pixel;
 367         __u32 activate = var->activate;
 368
 369         /* only allow 1/8 bit depth (8-bit is grayscale) */
 370         *var = picolcdfb_var;
 371         var->activate = activate;
 372         if (bpp >= 8) {
 373                 var->bits_per_pixel = 8;
 374                 var->red.length     = 8;
 375                 var->green.length   = 8;
 376                 var->blue.length    = 8;
 377         } else {
 378                 var->bits_per_pixel = 1;
 379                 var->red.length     = 1;
 380                 var->green.length   = 1;
 381                 var->blue.length    = 1;
 382         }
 383         return 0;
 384 }
 385
 386 static int picolcd_set_par(struct fb_info *info)
 387 {
 388         struct picolcd_fb_data *fbdata = info->par;
 389         u8 *tmp_fb, *o_fb;
 390         if (info->var.bits_per_pixel == fbdata->bpp)
 391                 return 0;
 392         /* switch between 1/8 bit depths */
 393         if (info->var.bits_per_pixel != 1 && info->var.bits_per_pixel != 8)
 394                 return -EINVAL;
 395
 396         o_fb   = fbdata->bitmap;
 397         tmp_fb = kmalloc(PICOLCDFB_SIZE*info->var.bits_per_pixel, GFP_KERNEL);
 398         if (!tmp_fb)
 399                 return -ENOMEM;
 400
 401         /* translate FB content to new bits-per-pixel */
 402         if (info->var.bits_per_pixel == 1) {
 403                 int i, b;
 404                 for (i = 0; i < PICOLCDFB_SIZE; i++) {
 405                         u8 p = 0;
 406                         for (b = 0; b < 8; b++) {
 407                                 p <<= 1;
 408                                 p |= o_fb[i*8+b] ? 0x01 : 0x00;
 409                         }
 410                         tmp_fb[i] = p;
 411                 }
 412                 memcpy(o_fb, tmp_fb, PICOLCDFB_SIZE);
 413                 info->fix.visual = FB_VISUAL_MONO01;
 414                 info->fix.line_length = PICOLCDFB_WIDTH / 8;
 415         } else {
 416                 int i;
 417                 memcpy(tmp_fb, o_fb, PICOLCDFB_SIZE);
 418                 for (i = 0; i < PICOLCDFB_SIZE * 8; i++)
 419                         o_fb[i] = tmp_fb[i/8] & (0x01 << (7 - i % 8)) ? 0xff : 0x00;
 420                 info->fix.visual = FB_VISUAL_DIRECTCOLOR;
 421                 info->fix.line_length = PICOLCDFB_WIDTH;
 422         }
 423
 424         kfree(tmp_fb);
 425         fbdata->bpp = info->var.bits_per_pixel;
 426         return 0;
 427 }
 428
 429 /* Note this can't be const because of struct fb_info definition */
 430 static struct fb_ops picolcdfb_ops = {
 431         .owner        = THIS_MODULE,
 432         .fb_destroy   = picolcd_fb_destroy,
 433         .fb_read      = fb_sys_read,
 434         .fb_write     = picolcd_fb_write,
 435         .fb_blank     = picolcd_fb_blank,
 436         .fb_fillrect  = picolcd_fb_fillrect,
 437         .fb_copyarea  = picolcd_fb_copyarea,
 438         .fb_imageblit = picolcd_fb_imageblit,
 439         .fb_check_var = picolcd_fb_check_var,
 440         .fb_set_par   = picolcd_set_par,
 441 };
 442
 443
 444 /* Callback from deferred IO workqueue */
 445 static void picolcd_fb_deferred_io(struct fb_info *info, struct list_head *pagelist)
 446 {
 447         picolcd_fb_update(info);
 448 }
 449
 450 static const struct fb_deferred_io picolcd_fb_defio = {
 451         .delay = HZ / PICOLCDFB_UPDATE_RATE_DEFAULT,
 452         .deferred_io = picolcd_fb_deferred_io,
 453 };
 454
 455
 456 /*
 457  * The "fb_update_rate" sysfs attribute
 458  */
 459 static ssize_t picolcd_fb_update_rate_show(struct device *dev,
 460                 struct device_attribute *attr, char *buf)
 461 {
 462         struct picolcd_data *data = dev_get_drvdata(dev);
 463         struct picolcd_fb_data *fbdata = data->fb_info->par;
 464         unsigned i, fb_update_rate = fbdata->update_rate;
 465         size_t ret = 0;
 466
 467         for (i = 1; i <= PICOLCDFB_UPDATE_RATE_LIMIT; i++)
 468                 if (ret >= PAGE_SIZE)
 469                         break;
 470                 else if (i == fb_update_rate)
 471                         ret += snprintf(buf+ret, PAGE_SIZE-ret, "[%u] ", i);
 472                 else
 473                         ret += snprintf(buf+ret, PAGE_SIZE-ret, "%u ", i);
 474         if (ret > 0)
 475                 buf[min(ret, (size_t)PAGE_SIZE)-1] = '\n';
 476         return ret;
 477 }
 478
 479 static ssize_t picolcd_fb_update_rate_store(struct device *dev,
 480                 struct device_attribute *attr, const char *buf, size_t count)
 481 {
 482         struct picolcd_data *data = dev_get_drvdata(dev);
 483         struct picolcd_fb_data *fbdata = data->fb_info->par;
 484         int i;
 485         unsigned u;
 486
 487         if (count < 1 || count > 10)
 488                 return -EINVAL;
 489
 490         i = sscanf(buf, "%u", &u);
 491         if (i != 1)
 492                 return -EINVAL;
 493
 494         if (u > PICOLCDFB_UPDATE_RATE_LIMIT)
 495                 return -ERANGE;
 496         else if (u == 0)
 497                 u = PICOLCDFB_UPDATE_RATE_DEFAULT;
 498
 499         fbdata->update_rate = u;
 500         data->fb_info->fbdefio->delay = HZ / fbdata->update_rate;
 501         return count;
 502 }
 503
 504 static DEVICE_ATTR(fb_update_rate, 0664, picolcd_fb_update_rate_show,
 505                 picolcd_fb_update_rate_store);
 506
 507 /* initialize Framebuffer device */
 508 int picolcd_init_framebuffer(struct picolcd_data *data)
 509 {
 510         struct device *dev = &data->hdev->dev;
 511         struct fb_info *info = NULL;
 512         struct picolcd_fb_data *fbdata = NULL;
 513         int i, error = -ENOMEM;
 514         u32 *palette;
 515
 516         /* The extra memory is:
 517          * - 256*u32 for pseudo_palette
 518          * - struct fb_deferred_io
 519          */
 520         info = framebuffer_alloc(256 * sizeof(u32) +
 521                         sizeof(struct fb_deferred_io) +
 522                         sizeof(struct picolcd_fb_data) +
 523                         PICOLCDFB_SIZE, dev);
 524         if (info == NULL) {
 525                 dev_err(dev, "failed to allocate a framebuffer\n");
 526                 goto err_nomem;
 527         }
 528
 529         info->fbdefio = info->par;
 530         *info->fbdefio = picolcd_fb_defio;
 531         info->par += sizeof(struct fb_deferred_io);
 532         palette = info->par;
 533         info->par += 256 * sizeof(u32);
 534         for (i = 0; i < 256; i++)
 535                 palette[i] = i > 0 && i < 16 ? 0xff : 0;
 536         info->pseudo_palette = palette;
 537         info->fbops = &picolcdfb_ops;
 538         info->var = picolcdfb_var;
 539         info->fix = picolcdfb_fix;
 540         info->fix.smem_len   = PICOLCDFB_SIZE*8;
 541         info->flags = FBINFO_FLAG_DEFAULT;
 542
 543         fbdata = info->par;
 544         spin_lock_init(&fbdata->lock);
 545         fbdata->picolcd = data;
 546         fbdata->update_rate = PICOLCDFB_UPDATE_RATE_DEFAULT;
 547         fbdata->bpp     = picolcdfb_var.bits_per_pixel;
 548         fbdata->force   = 1;
 549         fbdata->vbitmap = info->par + sizeof(struct picolcd_fb_data);
 550         fbdata->bitmap  = vmalloc(PICOLCDFB_SIZE*8);
 551         if (fbdata->bitmap == NULL) {
 552                 dev_err(dev, "can't get a free page for framebuffer\n");
 553                 goto err_nomem;
 554         }
 555         info->screen_base = (char __force __iomem *)fbdata->bitmap;
 556         info->fix.smem_start = (unsigned long)fbdata->bitmap;
 557         memset(fbdata->vbitmap, 0xff, PICOLCDFB_SIZE);
 558         data->fb_info = info;
 559
 560         error = picolcd_fb_reset(data, 1);
 561         if (error) {
 562                 dev_err(dev, "failed to configure display\n");
 563                 goto err_cleanup;
 564         }
 565
 566         error = device_create_file(dev, &dev_attr_fb_update_rate);
 567         if (error) {
 568                 dev_err(dev, "failed to create sysfs attributes\n");
 569                 goto err_cleanup;
 570         }
 571
 572         fb_deferred_io_init(info);
 573         error = register_framebuffer(info);
 574         if (error) {
 575                 dev_err(dev, "failed to register framebuffer\n");
 576                 goto err_sysfs;
 577         }
 578         return 0;
 579
 580 err_sysfs:
 581         device_remove_file(dev, &dev_attr_fb_update_rate);
 582         fb_deferred_io_cleanup(info);
 583 err_cleanup:
 584         data->fb_info    = NULL;
 585
 586 err_nomem:
 587         if (fbdata)
 588                 vfree(fbdata->bitmap);
 589         framebuffer_release(info);
 590         return error;
 591 }
 592
 593 void picolcd_exit_framebuffer(struct picolcd_data *data)
 594 {
 595         struct fb_info *info = data->fb_info;
 596         struct picolcd_fb_data *fbdata;
 597         unsigned long flags;
 598
 599         if (!info)
 600                 return;
 601
 602         device_remove_file(&data->hdev->dev, &dev_attr_fb_update_rate);
 603         fbdata = info->par;
 604
 605         /* disconnect framebuffer from HID dev */
 606         spin_lock_irqsave(&fbdata->lock, flags);
 607         fbdata->picolcd = NULL;
 608         spin_unlock_irqrestore(&fbdata->lock, flags);
 609
 610         /* make sure there is no running update - thus that fbdata->picolcd
 611          * once obtained under lock is guaranteed not to get free() under
 612          * the feet of the deferred work */
 613         flush_delayed_work(&info->deferred_work);
 614
 615         data->fb_info = NULL;
 616         unregister_framebuffer(info);
 617 }