/*
* 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");