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/*
* 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");
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