--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff