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.h>
31 #include <linux/of_clk.h>
32 #include <linux/of_platform.h>
33 #include <linux/parser.h>
34 #include <linux/regulator/consumer.h>
36 static const struct fb_fix_screeninfo simplefb_fix = {
38 .type = FB_TYPE_PACKED_PIXELS,
39 .visual = FB_VISUAL_TRUECOLOR,
40 .accel = FB_ACCEL_NONE,
43 static const struct fb_var_screeninfo simplefb_var = {
46 .activate = FB_ACTIVATE_NOW,
47 .vmode = FB_VMODE_NONINTERLACED,
50 #define PSEUDO_PALETTE_SIZE 16
52 static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
53 u_int transp, struct fb_info *info)
55 u32 *pal = info->pseudo_palette;
56 u32 cr = red >> (16 - info->var.red.length);
57 u32 cg = green >> (16 - info->var.green.length);
58 u32 cb = blue >> (16 - info->var.blue.length);
61 if (regno >= PSEUDO_PALETTE_SIZE)
64 value = (cr << info->var.red.offset) |
65 (cg << info->var.green.offset) |
66 (cb << info->var.blue.offset);
67 if (info->var.transp.length > 0) {
68 u32 mask = (1 << info->var.transp.length) - 1;
69 mask <<= info->var.transp.offset;
78 static void simplefb_clocks_destroy(struct simplefb_par *par);
79 static void simplefb_regulators_destroy(struct simplefb_par *par);
81 static void simplefb_destroy(struct fb_info *info)
83 simplefb_regulators_destroy(info->par);
84 simplefb_clocks_destroy(info->par);
85 if (info->screen_base)
86 iounmap(info->screen_base);
89 static struct fb_ops simplefb_ops = {
91 .fb_destroy = simplefb_destroy,
92 .fb_setcolreg = simplefb_setcolreg,
93 .fb_fillrect = cfb_fillrect,
94 .fb_copyarea = cfb_copyarea,
95 .fb_imageblit = cfb_imageblit,
98 static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS;
100 struct simplefb_params {
104 struct simplefb_format *format;
107 static int simplefb_parse_dt(struct platform_device *pdev,
108 struct simplefb_params *params)
110 struct device_node *np = pdev->dev.of_node;
115 ret = of_property_read_u32(np, "width", ¶ms->width);
117 dev_err(&pdev->dev, "Can't parse width property\n");
121 ret = of_property_read_u32(np, "height", ¶ms->height);
123 dev_err(&pdev->dev, "Can't parse height property\n");
127 ret = of_property_read_u32(np, "stride", ¶ms->stride);
129 dev_err(&pdev->dev, "Can't parse stride property\n");
133 ret = of_property_read_string(np, "format", &format);
135 dev_err(&pdev->dev, "Can't parse format property\n");
138 params->format = NULL;
139 for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
140 if (strcmp(format, simplefb_formats[i].name))
142 params->format = &simplefb_formats[i];
145 if (!params->format) {
146 dev_err(&pdev->dev, "Invalid format value\n");
153 static int simplefb_parse_pd(struct platform_device *pdev,
154 struct simplefb_params *params)
156 struct simplefb_platform_data *pd = dev_get_platdata(&pdev->dev);
159 params->width = pd->width;
160 params->height = pd->height;
161 params->stride = pd->stride;
163 params->format = NULL;
164 for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
165 if (strcmp(pd->format, simplefb_formats[i].name))
168 params->format = &simplefb_formats[i];
172 if (!params->format) {
173 dev_err(&pdev->dev, "Invalid format value\n");
180 struct simplefb_par {
181 u32 palette[PSEUDO_PALETTE_SIZE];
182 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
184 unsigned int clk_count;
187 #if defined CONFIG_OF && defined CONFIG_REGULATOR
188 bool regulators_enabled;
190 struct regulator **regulators;
194 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
196 * Clock handling code.
198 * Here we handle the clocks property of our "simple-framebuffer" dt node.
199 * This is necessary so that we can make sure that any clocks needed by
200 * the display engine that the bootloader set up for us (and for which it
201 * provided a simplefb dt node), stay up, for the life of the simplefb
204 * When the driver unloads, we cleanly disable, and then release the clocks.
206 * We only complain about errors here, no action is taken as the most likely
207 * error can only happen due to a mismatch between the bootloader which set
208 * up simplefb, and the clock definitions in the device tree. Chances are
209 * that there are no adverse effects, and if there are, a clean teardown of
210 * the fb probe will not help us much either. So just complain and carry on,
211 * and hope that the user actually gets a working fb at the end of things.
213 static int simplefb_clocks_get(struct simplefb_par *par,
214 struct platform_device *pdev)
216 struct device_node *np = pdev->dev.of_node;
220 if (dev_get_platdata(&pdev->dev) || !np)
223 par->clk_count = of_clk_get_parent_count(np);
227 par->clks = kcalloc(par->clk_count, sizeof(struct clk *), GFP_KERNEL);
231 for (i = 0; i < par->clk_count; i++) {
232 clock = of_clk_get(np, i);
234 if (PTR_ERR(clock) == -EPROBE_DEFER) {
237 clk_put(par->clks[i]);
240 return -EPROBE_DEFER;
242 dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
243 __func__, i, PTR_ERR(clock));
246 par->clks[i] = clock;
252 static void simplefb_clocks_enable(struct simplefb_par *par,
253 struct platform_device *pdev)
257 for (i = 0; i < par->clk_count; i++) {
259 ret = clk_prepare_enable(par->clks[i]);
262 "%s: failed to enable clock %d: %d\n",
264 clk_put(par->clks[i]);
269 par->clks_enabled = true;
272 static void simplefb_clocks_destroy(struct simplefb_par *par)
279 for (i = 0; i < par->clk_count; i++) {
281 if (par->clks_enabled)
282 clk_disable_unprepare(par->clks[i]);
283 clk_put(par->clks[i]);
290 static int simplefb_clocks_get(struct simplefb_par *par,
291 struct platform_device *pdev) { return 0; }
292 static void simplefb_clocks_enable(struct simplefb_par *par,
293 struct platform_device *pdev) { }
294 static void simplefb_clocks_destroy(struct simplefb_par *par) { }
297 #if defined CONFIG_OF && defined CONFIG_REGULATOR
299 #define SUPPLY_SUFFIX "-supply"
302 * Regulator handling code.
304 * Here we handle the num-supplies and vin*-supply properties of our
305 * "simple-framebuffer" dt node. This is necessary so that we can make sure
306 * that any regulators needed by the display hardware that the bootloader
307 * set up for us (and for which it provided a simplefb dt node), stay up,
308 * for the life of the simplefb driver.
310 * When the driver unloads, we cleanly disable, and then release the
313 * We only complain about errors here, no action is taken as the most likely
314 * error can only happen due to a mismatch between the bootloader which set
315 * up simplefb, and the regulator definitions in the device tree. Chances are
316 * that there are no adverse effects, and if there are, a clean teardown of
317 * the fb probe will not help us much either. So just complain and carry on,
318 * and hope that the user actually gets a working fb at the end of things.
320 static int simplefb_regulators_get(struct simplefb_par *par,
321 struct platform_device *pdev)
323 struct device_node *np = pdev->dev.of_node;
324 struct property *prop;
325 struct regulator *regulator;
327 int count = 0, i = 0;
329 if (dev_get_platdata(&pdev->dev) || !np)
332 /* Count the number of regulator supplies */
333 for_each_property_of_node(np, prop) {
334 p = strstr(prop->name, SUPPLY_SUFFIX);
335 if (p && p != prop->name)
342 par->regulators = devm_kcalloc(&pdev->dev, count,
343 sizeof(struct regulator *), GFP_KERNEL);
344 if (!par->regulators)
347 /* Get all the regulators */
348 for_each_property_of_node(np, prop) {
349 char name[32]; /* 32 is max size of property name */
351 p = strstr(prop->name, SUPPLY_SUFFIX);
352 if (!p || p == prop->name)
355 strlcpy(name, prop->name,
356 strlen(prop->name) - strlen(SUPPLY_SUFFIX) + 1);
357 regulator = devm_regulator_get_optional(&pdev->dev, name);
358 if (IS_ERR(regulator)) {
359 if (PTR_ERR(regulator) == -EPROBE_DEFER)
360 return -EPROBE_DEFER;
361 dev_err(&pdev->dev, "regulator %s not found: %ld\n",
362 name, PTR_ERR(regulator));
365 par->regulators[i++] = regulator;
367 par->regulator_count = i;
372 static void simplefb_regulators_enable(struct simplefb_par *par,
373 struct platform_device *pdev)
377 /* Enable all the regulators */
378 for (i = 0; i < par->regulator_count; i++) {
379 ret = regulator_enable(par->regulators[i]);
382 "failed to enable regulator %d: %d\n",
384 devm_regulator_put(par->regulators[i]);
385 par->regulators[i] = NULL;
388 par->regulators_enabled = true;
391 static void simplefb_regulators_destroy(struct simplefb_par *par)
395 if (!par->regulators || !par->regulators_enabled)
398 for (i = 0; i < par->regulator_count; i++)
399 if (par->regulators[i])
400 regulator_disable(par->regulators[i]);
403 static int simplefb_regulators_get(struct simplefb_par *par,
404 struct platform_device *pdev) { return 0; }
405 static void simplefb_regulators_enable(struct simplefb_par *par,
406 struct platform_device *pdev) { }
407 static void simplefb_regulators_destroy(struct simplefb_par *par) { }
410 static int simplefb_probe(struct platform_device *pdev)
413 struct simplefb_params params;
414 struct fb_info *info;
415 struct simplefb_par *par;
416 struct resource *mem;
418 if (fb_get_options("simplefb", NULL))
422 if (dev_get_platdata(&pdev->dev))
423 ret = simplefb_parse_pd(pdev, ¶ms);
424 else if (pdev->dev.of_node)
425 ret = simplefb_parse_dt(pdev, ¶ms);
430 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
432 dev_err(&pdev->dev, "No memory resource\n");
436 info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
439 platform_set_drvdata(pdev, info);
443 info->fix = simplefb_fix;
444 info->fix.smem_start = mem->start;
445 info->fix.smem_len = resource_size(mem);
446 info->fix.line_length = params.stride;
448 info->var = simplefb_var;
449 info->var.xres = params.width;
450 info->var.yres = params.height;
451 info->var.xres_virtual = params.width;
452 info->var.yres_virtual = params.height;
453 info->var.bits_per_pixel = params.format->bits_per_pixel;
454 info->var.red = params.format->red;
455 info->var.green = params.format->green;
456 info->var.blue = params.format->blue;
457 info->var.transp = params.format->transp;
459 info->apertures = alloc_apertures(1);
460 if (!info->apertures) {
462 goto error_fb_release;
464 info->apertures->ranges[0].base = info->fix.smem_start;
465 info->apertures->ranges[0].size = info->fix.smem_len;
467 info->fbops = &simplefb_ops;
468 info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE;
469 info->screen_base = ioremap_wc(info->fix.smem_start,
471 if (!info->screen_base) {
473 goto error_fb_release;
475 info->pseudo_palette = par->palette;
477 ret = simplefb_clocks_get(par, pdev);
481 ret = simplefb_regulators_get(par, pdev);
485 simplefb_clocks_enable(par, pdev);
486 simplefb_regulators_enable(par, pdev);
488 dev_info(&pdev->dev, "framebuffer at 0x%lx, 0x%x bytes, mapped to 0x%p\n",
489 info->fix.smem_start, info->fix.smem_len,
491 dev_info(&pdev->dev, "format=%s, mode=%dx%dx%d, linelength=%d\n",
493 info->var.xres, info->var.yres,
494 info->var.bits_per_pixel, info->fix.line_length);
496 ret = register_framebuffer(info);
498 dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
499 goto error_regulators;
502 dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node);
507 simplefb_regulators_destroy(par);
509 simplefb_clocks_destroy(par);
511 iounmap(info->screen_base);
513 framebuffer_release(info);
517 static int simplefb_remove(struct platform_device *pdev)
519 struct fb_info *info = platform_get_drvdata(pdev);
521 unregister_framebuffer(info);
522 framebuffer_release(info);
527 static const struct of_device_id simplefb_of_match[] = {
528 { .compatible = "simple-framebuffer", },
531 MODULE_DEVICE_TABLE(of, simplefb_of_match);
533 static struct platform_driver simplefb_driver = {
535 .name = "simple-framebuffer",
536 .of_match_table = simplefb_of_match,
538 .probe = simplefb_probe,
539 .remove = simplefb_remove,
542 static int __init simplefb_init(void)
545 struct device_node *np;
547 ret = platform_driver_register(&simplefb_driver);
551 if (IS_ENABLED(CONFIG_OF_ADDRESS) && of_chosen) {
552 for_each_child_of_node(of_chosen, np) {
553 if (of_device_is_compatible(np, "simple-framebuffer"))
554 of_platform_device_create(np, NULL, NULL);
561 fs_initcall(simplefb_init);
563 MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>");
564 MODULE_DESCRIPTION("Simple framebuffer driver");
565 MODULE_LICENSE("GPL v2");