diff options
Diffstat (limited to 'kernel/drivers/video/fbdev/simplefb.c')
-rw-r--r-- | kernel/drivers/video/fbdev/simplefb.c | 419 |
1 files changed, 419 insertions, 0 deletions
diff --git a/kernel/drivers/video/fbdev/simplefb.c b/kernel/drivers/video/fbdev/simplefb.c new file mode 100644 index 000000000..1085c0432 --- /dev/null +++ b/kernel/drivers/video/fbdev/simplefb.c @@ -0,0 +1,419 @@ +/* + * 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_data/simplefb.h> +#include <linux/platform_device.h> +#include <linux/clk-provider.h> +#include <linux/of_platform.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, +}; + +#define PSEUDO_PALETTE_SIZE 16 + +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 >= PSEUDO_PALETTE_SIZE) + 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 void simplefb_destroy(struct fb_info *info) +{ + if (info->screen_base) + iounmap(info->screen_base); +} + +static struct fb_ops simplefb_ops = { + .owner = THIS_MODULE, + .fb_destroy = simplefb_destroy, + .fb_setcolreg = simplefb_setcolreg, + .fb_fillrect = cfb_fillrect, + .fb_copyarea = cfb_copyarea, + .fb_imageblit = cfb_imageblit, +}; + +static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS; + +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_parse_pd(struct platform_device *pdev, + struct simplefb_params *params) +{ + struct simplefb_platform_data *pd = dev_get_platdata(&pdev->dev); + int i; + + params->width = pd->width; + params->height = pd->height; + params->stride = pd->stride; + + params->format = NULL; + for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) { + if (strcmp(pd->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; +} + +struct simplefb_par { + u32 palette[PSEUDO_PALETTE_SIZE]; +#if defined CONFIG_OF && defined CONFIG_COMMON_CLK + int clk_count; + struct clk **clks; +#endif +}; + +#if defined CONFIG_OF && defined CONFIG_COMMON_CLK +/* + * Clock handling code. + * + * Here we handle the clocks property of our "simple-framebuffer" dt node. + * This is necessary so that we can make sure that any clocks needed by + * the display engine that the bootloader set up for us (and for which it + * provided a simplefb dt node), stay up, for the life of the simplefb + * driver. + * + * When the driver unloads, we cleanly disable, and then release the clocks. + * + * We only complain about errors here, no action is taken as the most likely + * error can only happen due to a mismatch between the bootloader which set + * up simplefb, and the clock definitions in the device tree. Chances are + * that there are no adverse effects, and if there are, a clean teardown of + * the fb probe will not help us much either. So just complain and carry on, + * and hope that the user actually gets a working fb at the end of things. + */ +static int simplefb_clocks_init(struct simplefb_par *par, + struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct clk *clock; + int i, ret; + + if (dev_get_platdata(&pdev->dev) || !np) + return 0; + + par->clk_count = of_clk_get_parent_count(np); + if (par->clk_count <= 0) + return 0; + + par->clks = kcalloc(par->clk_count, sizeof(struct clk *), GFP_KERNEL); + if (!par->clks) + return -ENOMEM; + + for (i = 0; i < par->clk_count; i++) { + clock = of_clk_get(np, i); + if (IS_ERR(clock)) { + if (PTR_ERR(clock) == -EPROBE_DEFER) { + while (--i >= 0) { + if (par->clks[i]) + clk_put(par->clks[i]); + } + kfree(par->clks); + return -EPROBE_DEFER; + } + dev_err(&pdev->dev, "%s: clock %d not found: %ld\n", + __func__, i, PTR_ERR(clock)); + continue; + } + par->clks[i] = clock; + } + + for (i = 0; i < par->clk_count; i++) { + if (par->clks[i]) { + ret = clk_prepare_enable(par->clks[i]); + if (ret) { + dev_err(&pdev->dev, + "%s: failed to enable clock %d: %d\n", + __func__, i, ret); + clk_put(par->clks[i]); + par->clks[i] = NULL; + } + } + } + + return 0; +} + +static void simplefb_clocks_destroy(struct simplefb_par *par) +{ + int i; + + if (!par->clks) + return; + + for (i = 0; i < par->clk_count; i++) { + if (par->clks[i]) { + clk_disable_unprepare(par->clks[i]); + clk_put(par->clks[i]); + } + } + + kfree(par->clks); +} +#else +static int simplefb_clocks_init(struct simplefb_par *par, + struct platform_device *pdev) { return 0; } +static void simplefb_clocks_destroy(struct simplefb_par *par) { } +#endif + +static int simplefb_probe(struct platform_device *pdev) +{ + int ret; + struct simplefb_params params; + struct fb_info *info; + struct simplefb_par *par; + struct resource *mem; + + if (fb_get_options("simplefb", NULL)) + return -ENODEV; + + ret = -ENODEV; + if (dev_get_platdata(&pdev->dev)) + ret = simplefb_parse_pd(pdev, ¶ms); + else if (pdev->dev.of_node) + 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(struct simplefb_par), &pdev->dev); + if (!info) + return -ENOMEM; + platform_set_drvdata(pdev, info); + + par = info->par; + + 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->apertures = alloc_apertures(1); + if (!info->apertures) { + ret = -ENOMEM; + goto error_fb_release; + } + info->apertures->ranges[0].base = info->fix.smem_start; + info->apertures->ranges[0].size = info->fix.smem_len; + + info->fbops = &simplefb_ops; + info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE; + info->screen_base = ioremap_wc(info->fix.smem_start, + info->fix.smem_len); + if (!info->screen_base) { + ret = -ENOMEM; + goto error_fb_release; + } + info->pseudo_palette = par->palette; + + ret = simplefb_clocks_init(par, pdev); + if (ret < 0) + goto error_unmap; + + dev_info(&pdev->dev, "framebuffer at 0x%lx, 0x%x bytes, mapped to 0x%p\n", + info->fix.smem_start, info->fix.smem_len, + info->screen_base); + dev_info(&pdev->dev, "format=%s, mode=%dx%dx%d, linelength=%d\n", + params.format->name, + info->var.xres, info->var.yres, + info->var.bits_per_pixel, info->fix.line_length); + + ret = register_framebuffer(info); + if (ret < 0) { + dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret); + goto error_clocks; + } + + dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node); + + return 0; + +error_clocks: + simplefb_clocks_destroy(par); +error_unmap: + iounmap(info->screen_base); +error_fb_release: + framebuffer_release(info); + return ret; +} + +static int simplefb_remove(struct platform_device *pdev) +{ + struct fb_info *info = platform_get_drvdata(pdev); + struct simplefb_par *par = info->par; + + unregister_framebuffer(info); + simplefb_clocks_destroy(par); + 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", + .of_match_table = simplefb_of_match, + }, + .probe = simplefb_probe, + .remove = simplefb_remove, +}; + +static int __init simplefb_init(void) +{ + int ret; + struct device_node *np; + + ret = platform_driver_register(&simplefb_driver); + if (ret) + return ret; + + if (IS_ENABLED(CONFIG_OF_ADDRESS) && of_chosen) { + for_each_child_of_node(of_chosen, np) { + if (of_device_is_compatible(np, "simple-framebuffer")) + of_platform_device_create(np, NULL, NULL); + } + } + + return 0; +} + +fs_initcall(simplefb_init); + +MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>"); +MODULE_DESCRIPTION("Simple framebuffer driver"); +MODULE_LICENSE("GPL v2"); |