drivers/video/fbdev/simplefb.c

   1 /*
   2  * Simplest possible simple frame-buffer driver, as a platform device
   3  *
   4  * Copyright (c) 2013, Stephen Warren
   5  *
   6  * Based on q40fb.c, which was:
   7  * Copyright (C) 2001 Richard Zidlicky <rz@linux-m68k.org>
   8  *
   9  * Also based on offb.c, which was:
  10  * Copyright (C) 1997 Geert Uytterhoeven
  11  * Copyright (C) 1996 Paul Mackerras
  12  *
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms and conditions of the GNU General Public License,
  15  * version 2, as published by the Free Software Foundation.
  16  *
  17  * This program is distributed in the hope it will be useful, but WITHOUT
  18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  20  * more details.
  21  */
  22
  23 #include <linux/errno.h>
  24 #include <linux/fb.h>
  25 #include <linux/io.h>
  26 #include <linux/module.h>
  27 #include <linux/platform_data/simplefb.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/clk.h>
  30 #include <linux/clk-provider.h>
  31 #include <linux/of_platform.h>
  32
  33 static struct fb_fix_screeninfo simplefb_fix = {
  34         .id             = "simple",
  35         .type           = FB_TYPE_PACKED_PIXELS,
  36         .visual         = FB_VISUAL_TRUECOLOR,
  37         .accel          = FB_ACCEL_NONE,
  38 };
  39
  40 static struct fb_var_screeninfo simplefb_var = {
  41         .height         = -1,
  42         .width          = -1,
  43         .activate       = FB_ACTIVATE_NOW,
  44         .vmode          = FB_VMODE_NONINTERLACED,
  45 };
  46
  47 #define PSEUDO_PALETTE_SIZE 16
  48
  49 static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
  50                               u_int transp, struct fb_info *info)
  51 {
  52         u32 *pal = info->pseudo_palette;
  53         u32 cr = red >> (16 - info->var.red.length);
  54         u32 cg = green >> (16 - info->var.green.length);
  55         u32 cb = blue >> (16 - info->var.blue.length);
  56         u32 value;
  57
  58         if (regno >= PSEUDO_PALETTE_SIZE)
  59                 return -EINVAL;
  60
  61         value = (cr << info->var.red.offset) |
  62                 (cg << info->var.green.offset) |
  63                 (cb << info->var.blue.offset);
  64         if (info->var.transp.length > 0) {
  65                 u32 mask = (1 << info->var.transp.length) - 1;
  66                 mask <<= info->var.transp.offset;
  67                 value |= mask;
  68         }
  69         pal[regno] = value;
  70
  71         return 0;
  72 }
  73
  74 static void simplefb_destroy(struct fb_info *info)
  75 {
  76         if (info->screen_base)
  77                 iounmap(info->screen_base);
  78 }
  79
  80 static struct fb_ops simplefb_ops = {
  81         .owner          = THIS_MODULE,
  82         .fb_destroy     = simplefb_destroy,
  83         .fb_setcolreg   = simplefb_setcolreg,
  84         .fb_fillrect    = cfb_fillrect,
  85         .fb_copyarea    = cfb_copyarea,
  86         .fb_imageblit   = cfb_imageblit,
  87 };
  88
  89 static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS;
  90
  91 struct simplefb_params {
  92         u32 width;
  93         u32 height;
  94         u32 stride;
  95         struct simplefb_format *format;
  96 };
  97
  98 static int simplefb_parse_dt(struct platform_device *pdev,
  99                            struct simplefb_params *params)
 100 {
 101         struct device_node *np = pdev->dev.of_node;
 102         int ret;
 103         const char *format;
 104         int i;
 105
 106         ret = of_property_read_u32(np, "width", &params->width);
 107         if (ret) {
 108                 dev_err(&pdev->dev, "Can't parse width property\n");
 109                 return ret;
 110         }
 111
 112         ret = of_property_read_u32(np, "height", &params->height);
 113         if (ret) {
 114                 dev_err(&pdev->dev, "Can't parse height property\n");
 115                 return ret;
 116         }
 117
 118         ret = of_property_read_u32(np, "stride", &params->stride);
 119         if (ret) {
 120                 dev_err(&pdev->dev, "Can't parse stride property\n");
 121                 return ret;
 122         }
 123
 124         ret = of_property_read_string(np, "format", &format);
 125         if (ret) {
 126                 dev_err(&pdev->dev, "Can't parse format property\n");
 127                 return ret;
 128         }
 129         params->format = NULL;
 130         for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
 131                 if (strcmp(format, simplefb_formats[i].name))
 132                         continue;
 133                 params->format = &simplefb_formats[i];
 134                 break;
 135         }
 136         if (!params->format) {
 137                 dev_err(&pdev->dev, "Invalid format value\n");
 138                 return -EINVAL;
 139         }
 140
 141         return 0;
 142 }
 143
 144 static int simplefb_parse_pd(struct platform_device *pdev,
 145                              struct simplefb_params *params)
 146 {
 147         struct simplefb_platform_data *pd = dev_get_platdata(&pdev->dev);
 148         int i;
 149
 150         params->width = pd->width;
 151         params->height = pd->height;
 152         params->stride = pd->stride;
 153
 154         params->format = NULL;
 155         for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
 156                 if (strcmp(pd->format, simplefb_formats[i].name))
 157                         continue;
 158
 159                 params->format = &simplefb_formats[i];
 160                 break;
 161         }
 162
 163         if (!params->format) {
 164                 dev_err(&pdev->dev, "Invalid format value\n");
 165                 return -EINVAL;
 166         }
 167
 168         return 0;
 169 }
 170
 171 struct simplefb_par {
 172         u32 palette[PSEUDO_PALETTE_SIZE];
 173 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
 174         int clk_count;
 175         struct clk **clks;
 176 #endif
 177 };
 178
 179 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
 180 /*
 181  * Clock handling code.
 182  *
 183  * Here we handle the clocks property of our "simple-framebuffer" dt node.
 184  * This is necessary so that we can make sure that any clocks needed by
 185  * the display engine that the bootloader set up for us (and for which it
 186  * provided a simplefb dt node), stay up, for the life of the simplefb
 187  * driver.
 188  *
 189  * When the driver unloads, we cleanly disable, and then release the clocks.
 190  *
 191  * We only complain about errors here, no action is taken as the most likely
 192  * error can only happen due to a mismatch between the bootloader which set
 193  * up simplefb, and the clock definitions in the device tree. Chances are
 194  * that there are no adverse effects, and if there are, a clean teardown of
 195  * the fb probe will not help us much either. So just complain and carry on,
 196  * and hope that the user actually gets a working fb at the end of things.
 197  */
 198 static int simplefb_clocks_init(struct simplefb_par *par,
 199                                 struct platform_device *pdev)
 200 {
 201         struct device_node *np = pdev->dev.of_node;
 202         struct clk *clock;
 203         int i, ret;
 204
 205         if (dev_get_platdata(&pdev->dev) || !np)
 206                 return 0;
 207
 208         par->clk_count = of_clk_get_parent_count(np);
 209         if (par->clk_count <= 0)
 210                 return 0;
 211
 212         par->clks = kcalloc(par->clk_count, sizeof(struct clk *), GFP_KERNEL);
 213         if (!par->clks)
 214                 return -ENOMEM;
 215
 216         for (i = 0; i < par->clk_count; i++) {
 217                 clock = of_clk_get(np, i);
 218                 if (IS_ERR(clock)) {
 219                         if (PTR_ERR(clock) == -EPROBE_DEFER) {
 220                                 while (--i >= 0) {
 221                                         if (par->clks[i])
 222                                                 clk_put(par->clks[i]);
 223                                 }
 224                                 kfree(par->clks);
 225                                 return -EPROBE_DEFER;
 226                         }
 227                         dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
 228                                 __func__, i, PTR_ERR(clock));
 229                         continue;
 230                 }
 231                 par->clks[i] = clock;
 232         }
 233
 234         for (i = 0; i < par->clk_count; i++) {
 235                 if (par->clks[i]) {
 236                         ret = clk_prepare_enable(par->clks[i]);
 237                         if (ret) {
 238                                 dev_err(&pdev->dev,
 239                                         "%s: failed to enable clock %d: %d\n",
 240                                         __func__, i, ret);
 241                                 clk_put(par->clks[i]);
 242                                 par->clks[i] = NULL;
 243                         }
 244                 }
 245         }
 246
 247         return 0;
 248 }
 249
 250 static void simplefb_clocks_destroy(struct simplefb_par *par)
 251 {
 252         int i;
 253
 254         if (!par->clks)
 255                 return;
 256
 257         for (i = 0; i < par->clk_count; i++) {
 258                 if (par->clks[i]) {
 259                         clk_disable_unprepare(par->clks[i]);
 260                         clk_put(par->clks[i]);
 261                 }
 262         }
 263
 264         kfree(par->clks);
 265 }
 266 #else
 267 static int simplefb_clocks_init(struct simplefb_par *par,
 268         struct platform_device *pdev) { return 0; }
 269 static void simplefb_clocks_destroy(struct simplefb_par *par) { }
 270 #endif
 271
 272 static int simplefb_probe(struct platform_device *pdev)
 273 {
 274         int ret;
 275         struct simplefb_params params;
 276         struct fb_info *info;
 277         struct simplefb_par *par;
 278         struct resource *mem;
 279
 280         if (fb_get_options("simplefb", NULL))
 281                 return -ENODEV;
 282
 283         ret = -ENODEV;
 284         if (dev_get_platdata(&pdev->dev))
 285                 ret = simplefb_parse_pd(pdev, &params);
 286         else if (pdev->dev.of_node)
 287                 ret = simplefb_parse_dt(pdev, &params);
 288
 289         if (ret)
 290                 return ret;
 291
 292         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 293         if (!mem) {
 294                 dev_err(&pdev->dev, "No memory resource\n");
 295                 return -EINVAL;
 296         }
 297
 298         info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
 299         if (!info)
 300                 return -ENOMEM;
 301         platform_set_drvdata(pdev, info);
 302
 303         par = info->par;
 304
 305         info->fix = simplefb_fix;
 306         info->fix.smem_start = mem->start;
 307         info->fix.smem_len = resource_size(mem);
 308         info->fix.line_length = params.stride;
 309
 310         info->var = simplefb_var;
 311         info->var.xres = params.width;
 312         info->var.yres = params.height;
 313         info->var.xres_virtual = params.width;
 314         info->var.yres_virtual = params.height;
 315         info->var.bits_per_pixel = params.format->bits_per_pixel;
 316         info->var.red = params.format->red;
 317         info->var.green = params.format->green;
 318         info->var.blue = params.format->blue;
 319         info->var.transp = params.format->transp;
 320
 321         info->apertures = alloc_apertures(1);
 322         if (!info->apertures) {
 323                 ret = -ENOMEM;
 324                 goto error_fb_release;
 325         }
 326         info->apertures->ranges[0].base = info->fix.smem_start;
 327         info->apertures->ranges[0].size = info->fix.smem_len;
 328
 329         info->fbops = &simplefb_ops;
 330         info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE;
 331         info->screen_base = ioremap_wc(info->fix.smem_start,
 332                                        info->fix.smem_len);
 333         if (!info->screen_base) {
 334                 ret = -ENOMEM;
 335                 goto error_fb_release;
 336         }
 337         info->pseudo_palette = par->palette;
 338
 339         ret = simplefb_clocks_init(par, pdev);
 340         if (ret < 0)
 341                 goto error_unmap;
 342
 343         dev_info(&pdev->dev, "framebuffer at 0x%lx, 0x%x bytes, mapped to 0x%p\n",
 344                              info->fix.smem_start, info->fix.smem_len,
 345                              info->screen_base);
 346         dev_info(&pdev->dev, "format=%s, mode=%dx%dx%d, linelength=%d\n",
 347                              params.format->name,
 348                              info->var.xres, info->var.yres,
 349                              info->var.bits_per_pixel, info->fix.line_length);
 350
 351         ret = register_framebuffer(info);
 352         if (ret < 0) {
 353                 dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
 354                 goto error_clocks;
 355         }
 356
 357         dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node);
 358
 359         return 0;
 360
 361 error_clocks:
 362         simplefb_clocks_destroy(par);
 363 error_unmap:
 364         iounmap(info->screen_base);
 365 error_fb_release:
 366         framebuffer_release(info);
 367         return ret;
 368 }
 369
 370 static int simplefb_remove(struct platform_device *pdev)
 371 {
 372         struct fb_info *info = platform_get_drvdata(pdev);
 373         struct simplefb_par *par = info->par;
 374
 375         unregister_framebuffer(info);
 376         simplefb_clocks_destroy(par);
 377         framebuffer_release(info);
 378
 379         return 0;
 380 }
 381
 382 static const struct of_device_id simplefb_of_match[] = {
 383         { .compatible = "simple-framebuffer", },
 384         { },
 385 };
 386 MODULE_DEVICE_TABLE(of, simplefb_of_match);
 387
 388 static struct platform_driver simplefb_driver = {
 389         .driver = {
 390                 .name = "simple-framebuffer",
 391                 .of_match_table = simplefb_of_match,
 392         },
 393         .probe = simplefb_probe,
 394         .remove = simplefb_remove,
 395 };
 396
 397 static int __init simplefb_init(void)
 398 {
 399         int ret;
 400         struct device_node *np;
 401
 402         ret = platform_driver_register(&simplefb_driver);
 403         if (ret)
 404                 return ret;
 405
 406         if (IS_ENABLED(CONFIG_OF_ADDRESS) && of_chosen) {
 407                 for_each_child_of_node(of_chosen, np) {
 408                         if (of_device_is_compatible(np, "simple-framebuffer"))
 409                                 of_platform_device_create(np, NULL, NULL);
 410                 }
 411         }
 412
 413         return 0;
 414 }
 415
 416 fs_initcall(simplefb_init);
 417
 418 MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>");
 419 MODULE_DESCRIPTION("Simple framebuffer driver");
 420 MODULE_LICENSE("GPL v2");