2 * Simplest possible simple frame-buffer driver, as a platform device
4 * Copyright (c) 2013, Stephen Warren
6 * Based on q40fb.c, which was:
7 * Copyright (C) 2001 Richard Zidlicky <rz@linux-m68k.org>
9 * Also based on offb.c, which was:
10 * Copyright (C) 1997 Geert Uytterhoeven
11 * Copyright (C) 1996 Paul Mackerras
13 * This program is free software; you can redistribute it and/or modify it
14 * under the terms and conditions of the GNU General Public License,
15 * version 2, as published by the Free Software Foundation.
17 * This program is distributed in the hope it will be useful, but WITHOUT
18 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
23 #include <linux/errno.h>
26 #include <linux/module.h>
27 #include <linux/platform_data/simplefb.h>
28 #include <linux/platform_device.h>
29 #include <linux/clk-provider.h>
30 #include <linux/of_platform.h>
32 static struct fb_fix_screeninfo simplefb_fix = {
34 .type = FB_TYPE_PACKED_PIXELS,
35 .visual = FB_VISUAL_TRUECOLOR,
36 .accel = FB_ACCEL_NONE,
39 static struct fb_var_screeninfo simplefb_var = {
42 .activate = FB_ACTIVATE_NOW,
43 .vmode = FB_VMODE_NONINTERLACED,
46 #define PSEUDO_PALETTE_SIZE 16
48 static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
49 u_int transp, struct fb_info *info)
51 u32 *pal = info->pseudo_palette;
52 u32 cr = red >> (16 - info->var.red.length);
53 u32 cg = green >> (16 - info->var.green.length);
54 u32 cb = blue >> (16 - info->var.blue.length);
57 if (regno >= PSEUDO_PALETTE_SIZE)
60 value = (cr << info->var.red.offset) |
61 (cg << info->var.green.offset) |
62 (cb << info->var.blue.offset);
63 if (info->var.transp.length > 0) {
64 u32 mask = (1 << info->var.transp.length) - 1;
65 mask <<= info->var.transp.offset;
73 static void simplefb_destroy(struct fb_info *info)
75 if (info->screen_base)
76 iounmap(info->screen_base);
79 static struct fb_ops simplefb_ops = {
81 .fb_destroy = simplefb_destroy,
82 .fb_setcolreg = simplefb_setcolreg,
83 .fb_fillrect = cfb_fillrect,
84 .fb_copyarea = cfb_copyarea,
85 .fb_imageblit = cfb_imageblit,
88 static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS;
90 struct simplefb_params {
94 struct simplefb_format *format;
97 static int simplefb_parse_dt(struct platform_device *pdev,
98 struct simplefb_params *params)
100 struct device_node *np = pdev->dev.of_node;
105 ret = of_property_read_u32(np, "width", ¶ms->width);
107 dev_err(&pdev->dev, "Can't parse width property\n");
111 ret = of_property_read_u32(np, "height", ¶ms->height);
113 dev_err(&pdev->dev, "Can't parse height property\n");
117 ret = of_property_read_u32(np, "stride", ¶ms->stride);
119 dev_err(&pdev->dev, "Can't parse stride property\n");
123 ret = of_property_read_string(np, "format", &format);
125 dev_err(&pdev->dev, "Can't parse format property\n");
128 params->format = NULL;
129 for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
130 if (strcmp(format, simplefb_formats[i].name))
132 params->format = &simplefb_formats[i];
135 if (!params->format) {
136 dev_err(&pdev->dev, "Invalid format value\n");
143 static int simplefb_parse_pd(struct platform_device *pdev,
144 struct simplefb_params *params)
146 struct simplefb_platform_data *pd = dev_get_platdata(&pdev->dev);
149 params->width = pd->width;
150 params->height = pd->height;
151 params->stride = pd->stride;
153 params->format = NULL;
154 for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
155 if (strcmp(pd->format, simplefb_formats[i].name))
158 params->format = &simplefb_formats[i];
162 if (!params->format) {
163 dev_err(&pdev->dev, "Invalid format value\n");
170 struct simplefb_par {
171 u32 palette[PSEUDO_PALETTE_SIZE];
172 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
178 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
180 * Clock handling code.
182 * Here we handle the clocks property of our "simple-framebuffer" dt node.
183 * This is necessary so that we can make sure that any clocks needed by
184 * the display engine that the bootloader set up for us (and for which it
185 * provided a simplefb dt node), stay up, for the life of the simplefb
188 * When the driver unloads, we cleanly disable, and then release the clocks.
190 * We only complain about errors here, no action is taken as the most likely
191 * error can only happen due to a mismatch between the bootloader which set
192 * up simplefb, and the clock definitions in the device tree. Chances are
193 * that there are no adverse effects, and if there are, a clean teardown of
194 * the fb probe will not help us much either. So just complain and carry on,
195 * and hope that the user actually gets a working fb at the end of things.
197 static int simplefb_clocks_init(struct simplefb_par *par,
198 struct platform_device *pdev)
200 struct device_node *np = pdev->dev.of_node;
204 if (dev_get_platdata(&pdev->dev) || !np)
207 par->clk_count = of_clk_get_parent_count(np);
208 if (par->clk_count <= 0)
211 par->clks = kcalloc(par->clk_count, sizeof(struct clk *), GFP_KERNEL);
215 for (i = 0; i < par->clk_count; i++) {
216 clock = of_clk_get(np, i);
218 if (PTR_ERR(clock) == -EPROBE_DEFER) {
221 clk_put(par->clks[i]);
224 return -EPROBE_DEFER;
226 dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
227 __func__, i, PTR_ERR(clock));
230 par->clks[i] = clock;
233 for (i = 0; i < par->clk_count; i++) {
235 ret = clk_prepare_enable(par->clks[i]);
238 "%s: failed to enable clock %d: %d\n",
240 clk_put(par->clks[i]);
249 static void simplefb_clocks_destroy(struct simplefb_par *par)
256 for (i = 0; i < par->clk_count; i++) {
258 clk_disable_unprepare(par->clks[i]);
259 clk_put(par->clks[i]);
266 static int simplefb_clocks_init(struct simplefb_par *par,
267 struct platform_device *pdev) { return 0; }
268 static void simplefb_clocks_destroy(struct simplefb_par *par) { }
271 static int simplefb_probe(struct platform_device *pdev)
274 struct simplefb_params params;
275 struct fb_info *info;
276 struct simplefb_par *par;
277 struct resource *mem;
279 if (fb_get_options("simplefb", NULL))
283 if (dev_get_platdata(&pdev->dev))
284 ret = simplefb_parse_pd(pdev, ¶ms);
285 else if (pdev->dev.of_node)
286 ret = simplefb_parse_dt(pdev, ¶ms);
291 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
293 dev_err(&pdev->dev, "No memory resource\n");
297 info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
300 platform_set_drvdata(pdev, info);
304 info->fix = simplefb_fix;
305 info->fix.smem_start = mem->start;
306 info->fix.smem_len = resource_size(mem);
307 info->fix.line_length = params.stride;
309 info->var = simplefb_var;
310 info->var.xres = params.width;
311 info->var.yres = params.height;
312 info->var.xres_virtual = params.width;
313 info->var.yres_virtual = params.height;
314 info->var.bits_per_pixel = params.format->bits_per_pixel;
315 info->var.red = params.format->red;
316 info->var.green = params.format->green;
317 info->var.blue = params.format->blue;
318 info->var.transp = params.format->transp;
320 info->apertures = alloc_apertures(1);
321 if (!info->apertures) {
323 goto error_fb_release;
325 info->apertures->ranges[0].base = info->fix.smem_start;
326 info->apertures->ranges[0].size = info->fix.smem_len;
328 info->fbops = &simplefb_ops;
329 info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE;
330 info->screen_base = ioremap_wc(info->fix.smem_start,
332 if (!info->screen_base) {
334 goto error_fb_release;
336 info->pseudo_palette = par->palette;
338 ret = simplefb_clocks_init(par, pdev);
342 dev_info(&pdev->dev, "framebuffer at 0x%lx, 0x%x bytes, mapped to 0x%p\n",
343 info->fix.smem_start, info->fix.smem_len,
345 dev_info(&pdev->dev, "format=%s, mode=%dx%dx%d, linelength=%d\n",
347 info->var.xres, info->var.yres,
348 info->var.bits_per_pixel, info->fix.line_length);
350 ret = register_framebuffer(info);
352 dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
356 dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node);
361 simplefb_clocks_destroy(par);
363 iounmap(info->screen_base);
365 framebuffer_release(info);
369 static int simplefb_remove(struct platform_device *pdev)
371 struct fb_info *info = platform_get_drvdata(pdev);
372 struct simplefb_par *par = info->par;
374 unregister_framebuffer(info);
375 simplefb_clocks_destroy(par);
376 framebuffer_release(info);
381 static const struct of_device_id simplefb_of_match[] = {
382 { .compatible = "simple-framebuffer", },
385 MODULE_DEVICE_TABLE(of, simplefb_of_match);
387 static struct platform_driver simplefb_driver = {
389 .name = "simple-framebuffer",
390 .of_match_table = simplefb_of_match,
392 .probe = simplefb_probe,
393 .remove = simplefb_remove,
396 static int __init simplefb_init(void)
399 struct device_node *np;
401 ret = platform_driver_register(&simplefb_driver);
405 if (IS_ENABLED(CONFIG_OF) && of_chosen) {
406 for_each_child_of_node(of_chosen, np) {
407 if (of_device_is_compatible(np, "simple-framebuffer"))
408 of_platform_device_create(np, NULL, NULL);
415 fs_initcall(simplefb_init);
417 MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>");
418 MODULE_DESCRIPTION("Simple framebuffer driver");
419 MODULE_LICENSE("GPL v2");