[V2] video: implement a simple framebuffer driver

Message ID	1365043183-28905-1-git-send-email-swarren@wwwdotorg.org (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-fbdev-owner@vger.kernel.org> From: Stephen Warren <swarren@wwwdotorg.org> To: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de>, Olof Johansson <olof@lixom.net>, Rob Clark <robclark@gmail.com>, linux-fbdev@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, Stephen Warren <swarren@wwwdotorg.org> Subject: [PATCH V2] video: implement a simple framebuffer driver Date: Wed, 3 Apr 2013 20:39:43 -0600 Message-Id: <1365043183-28905-1-git-send-email-swarren@wwwdotorg.org> Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk

diff --git a/Documentation/devicetree/bindings/video/simple-framebuffer.txt b/Documentation/devicetree/bindings/video/simple-framebuffer.txt new file mode 100644 index 0000000..3ea4605 --- /dev/null +++ b/Documentation/devicetree/bindings/video/simple-framebuffer.txt @@ -0,0 +1,25 @@ +Simple Framebuffer + +A simple frame-buffer describes a raw memory region that may be rendered to, +with the assumption that the display hardware has already been set up to scan +out from that buffer. + +Required properties: +- compatible: "simple-framebuffer" +- reg: Should contain the location and size of the framebuffer memory. +- width: The width of the framebuffer in pixels. +- height: The height of the framebuffer in pixels. +- stride: The number of bytes in each line of the framebuffer. +- format: The format of the framebuffer surface. Valid values are: + - r5g6b5 (16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b). + +Example: + + framebuffer { + compatible = "simple-framebuffer"; + reg = <0x1d385000 (1600 * 1200 * 2)>; + width = <1600>; + height = <1200>; + stride = <(1600 * 2)>; + format = "r5g6b5"; + }; diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig index 0181a87..e946e9c 100644 --- a/drivers/video/Kconfig +++ b/drivers/video/Kconfig @@ -2462,6 +2462,23 @@ config FB_HYPERV help This framebuffer driver supports Microsoft Hyper-V Synthetic Video. +config FB_SIMPLE + bool "Simple framebuffer support" + depends on (FB = y) && OF + select FB_CFB_FILLRECT + select FB_CFB_COPYAREA + select FB_CFB_IMAGEBLIT + help + Say Y if you want support for a simple frame-buffer. + + This driver assumes that the display hardware has been initialized + before the kernel boots, and the kernel will simply render to the + pre-allocated frame buffer surface. + + Configuration re: surface address, size, and format must be provided + through device tree, or potentially plain old platform data in the + future. + source "drivers/video/omap/Kconfig" source "drivers/video/omap2/Kconfig" source "drivers/video/exynos/Kconfig" diff --git a/drivers/video/Makefile b/drivers/video/Makefile index 97f7b6d..859f1fa 100644 --- a/drivers/video/Makefile +++ b/drivers/video/Makefile @@ -166,6 +166,7 @@ obj-$(CONFIG_FB_MX3) += mx3fb.o obj-$(CONFIG_FB_DA8XX) += da8xx-fb.o obj-$(CONFIG_FB_MXS) += mxsfb.o obj-$(CONFIG_FB_SSD1307) += ssd1307fb.o +obj-$(CONFIG_FB_SIMPLE) += simplefb.o # the test framebuffer is last obj-$(CONFIG_FB_VIRTUAL) += vfb.o diff --git a/drivers/video/simplefb.c b/drivers/video/simplefb.c new file mode 100644 index 0000000..8105c3d --- /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; +}; + +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", &params->width); + if (ret) { + dev_err(&pdev->dev, "Can't parse width property\n"); + return ret; + } + + ret = of_property_read_u32(np, "height", &params->height); + if (ret) { + dev_err(&pdev->dev, "Can't parse height property\n"); + return ret; + } + + ret = of_property_read_u32(np, "stride", &params->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, &params); + 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");

[V2] video: implement a simple framebuffer driver

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