diff options
Diffstat (limited to 'drivers/video/simplefb.c')
| -rw-r--r-- | drivers/video/simplefb.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/drivers/video/simplefb.c b/drivers/video/simplefb.c new file mode 100644 index 0000000..e2e9e3e --- /dev/null +++ b/drivers/video/simplefb.c @@ -0,0 +1,234 @@ +/* + * Simplest possible simple frame-buffer driver, as a platform device + * + * Copyright (c) 2013, Stephen Warren + * + * Based on q40fb.c, which was: + * Copyright (C) 2001 Richard Zidlicky <rz@linux-m68k.org> + * + * Also based on offb.c, which was: + * Copyright (C) 1997 Geert Uytterhoeven + * Copyright (C) 1996 Paul Mackerras + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#include <linux/errno.h> +#include <linux/fb.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/platform_device.h> + +static struct fb_fix_screeninfo simplefb_fix = { + .id = "simple", + .type = FB_TYPE_PACKED_PIXELS, + .visual = FB_VISUAL_TRUECOLOR, + .accel = FB_ACCEL_NONE, +}; + +static struct fb_var_screeninfo simplefb_var = { + .height = -1, + .width = -1, + .activate = FB_ACTIVATE_NOW, + .vmode = FB_VMODE_NONINTERLACED, +}; + +static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue, + u_int transp, struct fb_info *info) +{ + u32 *pal = info->pseudo_palette; + u32 cr = red >> (16 - info->var.red.length); + u32 cg = green >> (16 - info->var.green.length); + u32 cb = blue >> (16 - info->var.blue.length); + u32 value; + + if (regno >= 16) + return -EINVAL; + + value = (cr << info->var.red.offset) | + (cg << info->var.green.offset) | + (cb << info->var.blue.offset); + if (info->var.transp.length > 0) { + u32 mask = (1 << info->var.transp.length) - 1; + mask <<= info->var.transp.offset; + value |= mask; + } + pal[regno] = value; + + return 0; +} + +static struct fb_ops simplefb_ops = { + .owner = THIS_MODULE, + .fb_setcolreg = simplefb_setcolreg, + .fb_fillrect = cfb_fillrect, + .fb_copyarea = cfb_copyarea, + .fb_imageblit = cfb_imageblit, +}; + +struct simplefb_format { + const char *name; + u32 bits_per_pixel; + struct fb_bitfield red; + struct fb_bitfield green; + struct fb_bitfield blue; + struct fb_bitfield transp; +}; + +static struct simplefb_format simplefb_formats[] = { + { "r5g6b5", 16, {11, 5}, {5, 6}, {0, 5}, {0, 0} }, +}; + +struct simplefb_params { + u32 width; + u32 height; + u32 stride; + struct simplefb_format *format; +}; + +static int simplefb_parse_dt(struct platform_device *pdev, + struct simplefb_params *params) +{ + struct device_node *np = pdev->dev.of_node; + int ret; + const char *format; + int i; + + ret = of_property_read_u32(np, "width", ¶ms->width); + if (ret) { + dev_err(&pdev->dev, "Can't parse width property\n"); + return ret; + } + + ret = of_property_read_u32(np, "height", ¶ms->height); + if (ret) { + dev_err(&pdev->dev, "Can't parse height property\n"); + return ret; + } + + ret = of_property_read_u32(np, "stride", ¶ms->stride); + if (ret) { + dev_err(&pdev->dev, "Can't parse stride property\n"); + return ret; + } + + ret = of_property_read_string(np, "format", &format); + if (ret) { + dev_err(&pdev->dev, "Can't parse format property\n"); + return ret; + } + params->format = NULL; + for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) { + if (strcmp(format, simplefb_formats[i].name)) + continue; + params->format = &simplefb_formats[i]; + break; + } + if (!params->format) { + dev_err(&pdev->dev, "Invalid format value\n"); + return -EINVAL; + } + + return 0; +} + +static int simplefb_probe(struct platform_device *pdev) +{ + int ret; + struct simplefb_params params; + struct fb_info *info; + struct resource *mem; + + if (fb_get_options("simplefb", NULL)) + return -ENODEV; + + ret = simplefb_parse_dt(pdev, ¶ms); + if (ret) + return ret; + + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!mem) { + dev_err(&pdev->dev, "No memory resource\n"); + return -EINVAL; + } + + info = framebuffer_alloc(sizeof(u32) * 16, &pdev->dev); + if (!info) + return -ENOMEM; + platform_set_drvdata(pdev, info); + + info->fix = simplefb_fix; + info->fix.smem_start = mem->start; + info->fix.smem_len = resource_size(mem); + info->fix.line_length = params.stride; + + info->var = simplefb_var; + info->var.xres = params.width; + info->var.yres = params.height; + info->var.xres_virtual = params.width; + info->var.yres_virtual = params.height; + info->var.bits_per_pixel = params.format->bits_per_pixel; + info->var.red = params.format->red; + info->var.green = params.format->green; + info->var.blue = params.format->blue; + info->var.transp = params.format->transp; + + info->fbops = &simplefb_ops; + info->flags = FBINFO_DEFAULT; + info->screen_base = devm_ioremap(&pdev->dev, info->fix.smem_start, + info->fix.smem_len); + if (!info->screen_base) { + framebuffer_release(info); + return -ENODEV; + } + info->pseudo_palette = (void *)(info + 1); + + ret = register_framebuffer(info); + if (ret < 0) { + dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret); + framebuffer_release(info); + return ret; + } + + dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node); + + return 0; +} + +static int simplefb_remove(struct platform_device *pdev) +{ + struct fb_info *info = platform_get_drvdata(pdev); + + unregister_framebuffer(info); + framebuffer_release(info); + + return 0; +} + +static const struct of_device_id simplefb_of_match[] = { + { .compatible = "simple-framebuffer", }, + { }, +}; +MODULE_DEVICE_TABLE(of, simplefb_of_match); + +static struct platform_driver simplefb_driver = { + .driver = { + .name = "simple-framebuffer", + .owner = THIS_MODULE, + .of_match_table = simplefb_of_match, + }, + .probe = simplefb_probe, + .remove = simplefb_remove, +}; +module_platform_driver(simplefb_driver); + +MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>"); +MODULE_DESCRIPTION("Simple framebuffer driver"); +MODULE_LICENSE("GPL v2"); |
