drivers/video/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
  30 static struct fb_fix_screeninfo simplefb_fix = {
  31         .id             = "simple",
  32         .type           = FB_TYPE_PACKED_PIXELS,
  33         .visual         = FB_VISUAL_TRUECOLOR,
  34         .accel          = FB_ACCEL_NONE,
  35 };
  36
  37 static struct fb_var_screeninfo simplefb_var = {
  38         .height         = -1,
  39         .width          = -1,
  40         .activate       = FB_ACTIVATE_NOW,
  41         .vmode          = FB_VMODE_NONINTERLACED,
  42 };
  43
  44 static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
  45                               u_int transp, struct fb_info *info)
  46 {
  47         u32 *pal = info->pseudo_palette;
  48         u32 cr = red >> (16 - info->var.red.length);
  49         u32 cg = green >> (16 - info->var.green.length);
  50         u32 cb = blue >> (16 - info->var.blue.length);
  51         u32 value;
  52
  53         if (regno >= 16)
  54                 return -EINVAL;
  55
  56         value = (cr << info->var.red.offset) |
  57                 (cg << info->var.green.offset) |
  58                 (cb << info->var.blue.offset);
  59         if (info->var.transp.length > 0) {
  60                 u32 mask = (1 << info->var.transp.length) - 1;
  61                 mask <<= info->var.transp.offset;
  62                 value |= mask;
  63         }
  64         pal[regno] = value;
  65
  66         return 0;
  67 }
  68
  69 static void simplefb_destroy(struct fb_info *info)
  70 {
  71         if (info->screen_base)
  72                 iounmap(info->screen_base);
  73 }
  74
  75 static struct fb_ops simplefb_ops = {
  76         .owner          = THIS_MODULE,
  77         .fb_destroy     = simplefb_destroy,
  78         .fb_setcolreg   = simplefb_setcolreg,
  79         .fb_fillrect    = cfb_fillrect,
  80         .fb_copyarea    = cfb_copyarea,
  81         .fb_imageblit   = cfb_imageblit,
  82 };
  83
  84 static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS;
  85
  86 struct simplefb_params {
  87         u32 width;
  88         u32 height;
  89         u32 stride;
  90         struct simplefb_format *format;
  91 };
  92
  93 static int simplefb_parse_dt(struct platform_device *pdev,
  94                            struct simplefb_params *params)
  95 {
  96         struct device_node *np = pdev->dev.of_node;
  97         int ret;
  98         const char *format;
  99         int i;
 100
 101         ret = of_property_read_u32(np, "width", &params->width);
 102         if (ret) {
 103                 dev_err(&pdev->dev, "Can't parse width property\n");
 104                 return ret;
 105         }
 106
 107         ret = of_property_read_u32(np, "height", &params->height);
 108         if (ret) {
 109                 dev_err(&pdev->dev, "Can't parse height property\n");
 110                 return ret;
 111         }
 112
 113         ret = of_property_read_u32(np, "stride", &params->stride);
 114         if (ret) {
 115                 dev_err(&pdev->dev, "Can't parse stride property\n");
 116                 return ret;
 117         }
 118
 119         ret = of_property_read_string(np, "format", &format);
 120         if (ret) {
 121                 dev_err(&pdev->dev, "Can't parse format property\n");
 122                 return ret;
 123         }
 124         params->format = NULL;
 125         for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
 126                 if (strcmp(format, simplefb_formats[i].name))
 127                         continue;
 128                 params->format = &simplefb_formats[i];
 129                 break;
 130         }
 131         if (!params->format) {
 132                 dev_err(&pdev->dev, "Invalid format value\n");
 133                 return -EINVAL;
 134         }
 135
 136         return 0;
 137 }
 138
 139 static int simplefb_parse_pd(struct platform_device *pdev,
 140                              struct simplefb_params *params)
 141 {
 142         struct simplefb_platform_data *pd = dev_get_platdata(&pdev->dev);
 143         int i;
 144
 145         params->width = pd->width;
 146         params->height = pd->height;
 147         params->stride = pd->stride;
 148
 149         params->format = NULL;
 150         for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
 151                 if (strcmp(pd->format, simplefb_formats[i].name))
 152                         continue;
 153
 154                 params->format = &simplefb_formats[i];
 155                 break;
 156         }
 157
 158         if (!params->format) {
 159                 dev_err(&pdev->dev, "Invalid format value\n");
 160                 return -EINVAL;
 161         }
 162
 163         return 0;
 164 }
 165
 166 static int simplefb_probe(struct platform_device *pdev)
 167 {
 168         int ret;
 169         struct simplefb_params params;
 170         struct fb_info *info;
 171         struct resource *mem;
 172
 173         if (fb_get_options("simplefb", NULL))
 174                 return -ENODEV;
 175
 176         ret = -ENODEV;
 177         if (dev_get_platdata(&pdev->dev))
 178                 ret = simplefb_parse_pd(pdev, &params);
 179         else if (pdev->dev.of_node)
 180                 ret = simplefb_parse_dt(pdev, &params);
 181
 182         if (ret)
 183                 return ret;
 184
 185         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 186         if (!mem) {
 187                 dev_err(&pdev->dev, "No memory resource\n");
 188                 return -EINVAL;
 189         }
 190
 191         info = framebuffer_alloc(sizeof(u32) * 16, &pdev->dev);
 192         if (!info)
 193                 return -ENOMEM;
 194         platform_set_drvdata(pdev, info);
 195
 196         info->fix = simplefb_fix;
 197         info->fix.smem_start = mem->start;
 198         info->fix.smem_len = resource_size(mem);
 199         info->fix.line_length = params.stride;
 200
 201         info->var = simplefb_var;
 202         info->var.xres = params.width;
 203         info->var.yres = params.height;
 204         info->var.xres_virtual = params.width;
 205         info->var.yres_virtual = params.height;
 206         info->var.bits_per_pixel = params.format->bits_per_pixel;
 207         info->var.red = params.format->red;
 208         info->var.green = params.format->green;
 209         info->var.blue = params.format->blue;
 210         info->var.transp = params.format->transp;
 211
 212         info->apertures = alloc_apertures(1);
 213         if (!info->apertures) {
 214                 framebuffer_release(info);
 215                 return -ENOMEM;
 216         }
 217         info->apertures->ranges[0].base = info->fix.smem_start;
 218         info->apertures->ranges[0].size = info->fix.smem_len;
 219
 220         info->fbops = &simplefb_ops;
 221         info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE;
 222         info->screen_base = ioremap_wc(info->fix.smem_start,
 223                                        info->fix.smem_len);
 224         if (!info->screen_base) {
 225                 framebuffer_release(info);
 226                 return -ENODEV;
 227         }
 228         info->pseudo_palette = (void *)(info + 1);
 229
 230         dev_info(&pdev->dev, "framebuffer at 0x%lx, 0x%x bytes, mapped to 0x%p\n",
 231                              info->fix.smem_start, info->fix.smem_len,
 232                              info->screen_base);
 233         dev_info(&pdev->dev, "format=%s, mode=%dx%dx%d, linelength=%d\n",
 234                              params.format->name,
 235                              info->var.xres, info->var.yres,
 236                              info->var.bits_per_pixel, info->fix.line_length);
 237
 238         ret = register_framebuffer(info);
 239         if (ret < 0) {
 240                 dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
 241                 iounmap(info->screen_base);
 242                 framebuffer_release(info);
 243                 return ret;
 244         }
 245
 246         dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node);
 247
 248         return 0;
 249 }
 250
 251 static int simplefb_remove(struct platform_device *pdev)
 252 {
 253         struct fb_info *info = platform_get_drvdata(pdev);
 254
 255         unregister_framebuffer(info);
 256         framebuffer_release(info);
 257
 258         return 0;
 259 }
 260
 261 static const struct of_device_id simplefb_of_match[] = {
 262         { .compatible = "simple-framebuffer", },
 263         { },
 264 };
 265 MODULE_DEVICE_TABLE(of, simplefb_of_match);
 266
 267 static struct platform_driver simplefb_driver = {
 268         .driver = {
 269                 .name = "simple-framebuffer",
 270                 .owner = THIS_MODULE,
 271                 .of_match_table = simplefb_of_match,
 272         },
 273         .probe = simplefb_probe,
 274         .remove = simplefb_remove,
 275 };
 276 module_platform_driver(simplefb_driver);
 277
 278 MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>");
 279 MODULE_DESCRIPTION("Simple framebuffer driver");
 280 MODULE_LICENSE("GPL v2");