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 struct fb_ops simplefb_ops = {
  70         .owner          = THIS_MODULE,
  71         .fb_setcolreg   = simplefb_setcolreg,
  72         .fb_fillrect    = cfb_fillrect,
  73         .fb_copyarea    = cfb_copyarea,
  74         .fb_imageblit   = cfb_imageblit,
  75 };
  76
  77 static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS;
  78
  79 struct simplefb_params {
  80         u32 width;
  81         u32 height;
  82         u32 stride;
  83         struct simplefb_format *format;
  84 };
  85
  86 static int simplefb_parse_dt(struct platform_device *pdev,
  87                            struct simplefb_params *params)
  88 {
  89         struct device_node *np = pdev->dev.of_node;
  90         int ret;
  91         const char *format;
  92         int i;
  93
  94         ret = of_property_read_u32(np, "width", &params->width);
  95         if (ret) {
  96                 dev_err(&pdev->dev, "Can't parse width property\n");
  97                 return ret;
  98         }
  99
 100         ret = of_property_read_u32(np, "height", &params->height);
 101         if (ret) {
 102                 dev_err(&pdev->dev, "Can't parse height property\n");
 103                 return ret;
 104         }
 105
 106         ret = of_property_read_u32(np, "stride", &params->stride);
 107         if (ret) {
 108                 dev_err(&pdev->dev, "Can't parse stride property\n");
 109                 return ret;
 110         }
 111
 112         ret = of_property_read_string(np, "format", &format);
 113         if (ret) {
 114                 dev_err(&pdev->dev, "Can't parse format property\n");
 115                 return ret;
 116         }
 117         params->format = NULL;
 118         for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
 119                 if (strcmp(format, simplefb_formats[i].name))
 120                         continue;
 121                 params->format = &simplefb_formats[i];
 122                 break;
 123         }
 124         if (!params->format) {
 125                 dev_err(&pdev->dev, "Invalid format value\n");
 126                 return -EINVAL;
 127         }
 128
 129         return 0;
 130 }
 131
 132 static int simplefb_parse_pd(struct platform_device *pdev,
 133                              struct simplefb_params *params)
 134 {
 135         struct simplefb_platform_data *pd = pdev->dev.platform_data;
 136         int i;
 137
 138         params->width = pd->width;
 139         params->height = pd->height;
 140         params->stride = pd->stride;
 141
 142         params->format = NULL;
 143         for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
 144                 if (strcmp(pd->format, simplefb_formats[i].name))
 145                         continue;
 146
 147                 params->format = &simplefb_formats[i];
 148                 break;
 149         }
 150
 151         if (!params->format) {
 152                 dev_err(&pdev->dev, "Invalid format value\n");
 153                 return -EINVAL;
 154         }
 155
 156         return 0;
 157 }
 158
 159 static int simplefb_probe(struct platform_device *pdev)
 160 {
 161         int ret;
 162         struct simplefb_params params;
 163         struct fb_info *info;
 164         struct resource *mem;
 165
 166         if (fb_get_options("simplefb", NULL))
 167                 return -ENODEV;
 168
 169         ret = -ENODEV;
 170         if (pdev->dev.platform_data)
 171                 ret = simplefb_parse_pd(pdev, &params);
 172         else if (pdev->dev.of_node)
 173                 ret = simplefb_parse_dt(pdev, &params);
 174
 175         if (ret)
 176                 return ret;
 177
 178         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 179         if (!mem) {
 180                 dev_err(&pdev->dev, "No memory resource\n");
 181                 return -EINVAL;
 182         }
 183
 184         info = framebuffer_alloc(sizeof(u32) * 16, &pdev->dev);
 185         if (!info)
 186                 return -ENOMEM;
 187         platform_set_drvdata(pdev, info);
 188
 189         info->fix = simplefb_fix;
 190         info->fix.smem_start = mem->start;
 191         info->fix.smem_len = resource_size(mem);
 192         info->fix.line_length = params.stride;
 193
 194         info->var = simplefb_var;
 195         info->var.xres = params.width;
 196         info->var.yres = params.height;
 197         info->var.xres_virtual = params.width;
 198         info->var.yres_virtual = params.height;
 199         info->var.bits_per_pixel = params.format->bits_per_pixel;
 200         info->var.red = params.format->red;
 201         info->var.green = params.format->green;
 202         info->var.blue = params.format->blue;
 203         info->var.transp = params.format->transp;
 204
 205         info->apertures = alloc_apertures(1);
 206         if (!info->apertures) {
 207                 framebuffer_release(info);
 208                 return -ENOMEM;
 209         }
 210         info->apertures->ranges[0].base = info->fix.smem_start;
 211         info->apertures->ranges[0].size = info->fix.smem_len;
 212
 213         info->fbops = &simplefb_ops;
 214         info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE;
 215         info->screen_base = devm_ioremap(&pdev->dev, info->fix.smem_start,
 216                                          info->fix.smem_len);
 217         if (!info->screen_base) {
 218                 framebuffer_release(info);
 219                 return -ENODEV;
 220         }
 221         info->pseudo_palette = (void *)(info + 1);
 222
 223         ret = register_framebuffer(info);
 224         if (ret < 0) {
 225                 dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
 226                 framebuffer_release(info);
 227                 return ret;
 228         }
 229
 230         dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node);
 231
 232         return 0;
 233 }
 234
 235 static int simplefb_remove(struct platform_device *pdev)
 236 {
 237         struct fb_info *info = platform_get_drvdata(pdev);
 238
 239         unregister_framebuffer(info);
 240         framebuffer_release(info);
 241
 242         return 0;
 243 }
 244
 245 static const struct of_device_id simplefb_of_match[] = {
 246         { .compatible = "simple-framebuffer", },
 247         { },
 248 };
 249 MODULE_DEVICE_TABLE(of, simplefb_of_match);
 250
 251 static struct platform_driver simplefb_driver = {
 252         .driver = {
 253                 .name = "simple-framebuffer",
 254                 .owner = THIS_MODULE,
 255                 .of_match_table = simplefb_of_match,
 256         },
 257         .probe = simplefb_probe,
 258         .remove = simplefb_remove,
 259 };
 260 module_platform_driver(simplefb_driver);
 261
 262 MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>");
 263 MODULE_DESCRIPTION("Simple framebuffer driver");
 264 MODULE_LICENSE("GPL v2");