1/*
2 * Simplest possible simple frame-buffer driver, as a platform device
3 *
4 * Copyright (c) 2013, Stephen Warren
5 *
6 * Based on q40fb.c, which was:
7 * Copyright (C) 2001 Richard Zidlicky <rz@linux-m68k.org>
8 *
9 * Also based on offb.c, which was:
10 * Copyright (C) 1997 Geert Uytterhoeven
11 * Copyright (C) 1996 Paul Mackerras
12 *
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.
16 *
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
20 * more details.
21 */
22
23#include <linux/errno.h>
24#include <linux/fb.h>
25#include <linux/io.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>
31
32static struct fb_fix_screeninfo simplefb_fix = {
33	.id		= "simple",
34	.type		= FB_TYPE_PACKED_PIXELS,
35	.visual		= FB_VISUAL_TRUECOLOR,
36	.accel		= FB_ACCEL_NONE,
37};
38
39static struct fb_var_screeninfo simplefb_var = {
40	.height		= -1,
41	.width		= -1,
42	.activate	= FB_ACTIVATE_NOW,
43	.vmode		= FB_VMODE_NONINTERLACED,
44};
45
46#define PSEUDO_PALETTE_SIZE 16
47
48static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
49			      u_int transp, struct fb_info *info)
50{
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);
55	u32 value;
56
57	if (regno >= PSEUDO_PALETTE_SIZE)
58		return -EINVAL;
59
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;
66		value |= mask;
67	}
68	pal[regno] = value;
69
70	return 0;
71}
72
73static void simplefb_destroy(struct fb_info *info)
74{
75	if (info->screen_base)
76		iounmap(info->screen_base);
77}
78
79static struct fb_ops simplefb_ops = {
80	.owner		= THIS_MODULE,
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,
86};
87
88static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS;
89
90struct simplefb_params {
91	u32 width;
92	u32 height;
93	u32 stride;
94	struct simplefb_format *format;
95};
96
97static int simplefb_parse_dt(struct platform_device *pdev,
98			   struct simplefb_params *params)
99{
100	struct device_node *np = pdev->dev.of_node;
101	int ret;
102	const char *format;
103	int i;
104
105	ret = of_property_read_u32(np, "width", &params->width);
106	if (ret) {
107		dev_err(&pdev->dev, "Can't parse width property\n");
108		return ret;
109	}
110
111	ret = of_property_read_u32(np, "height", &params->height);
112	if (ret) {
113		dev_err(&pdev->dev, "Can't parse height property\n");
114		return ret;
115	}
116
117	ret = of_property_read_u32(np, "stride", &params->stride);
118	if (ret) {
119		dev_err(&pdev->dev, "Can't parse stride property\n");
120		return ret;
121	}
122
123	ret = of_property_read_string(np, "format", &format);
124	if (ret) {
125		dev_err(&pdev->dev, "Can't parse format property\n");
126		return ret;
127	}
128	params->format = NULL;
129	for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
130		if (strcmp(format, simplefb_formats[i].name))
131			continue;
132		params->format = &simplefb_formats[i];
133		break;
134	}
135	if (!params->format) {
136		dev_err(&pdev->dev, "Invalid format value\n");
137		return -EINVAL;
138	}
139
140	return 0;
141}
142
143static int simplefb_parse_pd(struct platform_device *pdev,
144			     struct simplefb_params *params)
145{
146	struct simplefb_platform_data *pd = dev_get_platdata(&pdev->dev);
147	int i;
148
149	params->width = pd->width;
150	params->height = pd->height;
151	params->stride = pd->stride;
152
153	params->format = NULL;
154	for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
155		if (strcmp(pd->format, simplefb_formats[i].name))
156			continue;
157
158		params->format = &simplefb_formats[i];
159		break;
160	}
161
162	if (!params->format) {
163		dev_err(&pdev->dev, "Invalid format value\n");
164		return -EINVAL;
165	}
166
167	return 0;
168}
169
170struct simplefb_par {
171	u32 palette[PSEUDO_PALETTE_SIZE];
172#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
173	int clk_count;
174	struct clk **clks;
175#endif
176};
177
178#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
179/*
180 * Clock handling code.
181 *
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
186 * driver.
187 *
188 * When the driver unloads, we cleanly disable, and then release the clocks.
189 *
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.
196 */
197static int simplefb_clocks_init(struct simplefb_par *par,
198				struct platform_device *pdev)
199{
200	struct device_node *np = pdev->dev.of_node;
201	struct clk *clock;
202	int i, ret;
203
204	if (dev_get_platdata(&pdev->dev) || !np)
205		return 0;
206
207	par->clk_count = of_clk_get_parent_count(np);
208	if (par->clk_count <= 0)
209		return 0;
210
211	par->clks = kcalloc(par->clk_count, sizeof(struct clk *), GFP_KERNEL);
212	if (!par->clks)
213		return -ENOMEM;
214
215	for (i = 0; i < par->clk_count; i++) {
216		clock = of_clk_get(np, i);
217		if (IS_ERR(clock)) {
218			if (PTR_ERR(clock) == -EPROBE_DEFER) {
219				while (--i >= 0) {
220					if (par->clks[i])
221						clk_put(par->clks[i]);
222				}
223				kfree(par->clks);
224				return -EPROBE_DEFER;
225			}
226			dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
227				__func__, i, PTR_ERR(clock));
228			continue;
229		}
230		par->clks[i] = clock;
231	}
232
233	for (i = 0; i < par->clk_count; i++) {
234		if (par->clks[i]) {
235			ret = clk_prepare_enable(par->clks[i]);
236			if (ret) {
237				dev_err(&pdev->dev,
238					"%s: failed to enable clock %d: %d\n",
239					__func__, i, ret);
240				clk_put(par->clks[i]);
241				par->clks[i] = NULL;
242			}
243		}
244	}
245
246	return 0;
247}
248
249static void simplefb_clocks_destroy(struct simplefb_par *par)
250{
251	int i;
252
253	if (!par->clks)
254		return;
255
256	for (i = 0; i < par->clk_count; i++) {
257		if (par->clks[i]) {
258			clk_disable_unprepare(par->clks[i]);
259			clk_put(par->clks[i]);
260		}
261	}
262
263	kfree(par->clks);
264}
265#else
266static int simplefb_clocks_init(struct simplefb_par *par,
267	struct platform_device *pdev) { return 0; }
268static void simplefb_clocks_destroy(struct simplefb_par *par) { }
269#endif
270
271static int simplefb_probe(struct platform_device *pdev)
272{
273	int ret;
274	struct simplefb_params params;
275	struct fb_info *info;
276	struct simplefb_par *par;
277	struct resource *mem;
278
279	if (fb_get_options("simplefb", NULL))
280		return -ENODEV;
281
282	ret = -ENODEV;
283	if (dev_get_platdata(&pdev->dev))
284		ret = simplefb_parse_pd(pdev, &params);
285	else if (pdev->dev.of_node)
286		ret = simplefb_parse_dt(pdev, &params);
287
288	if (ret)
289		return ret;
290
291	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
292	if (!mem) {
293		dev_err(&pdev->dev, "No memory resource\n");
294		return -EINVAL;
295	}
296
297	info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
298	if (!info)
299		return -ENOMEM;
300	platform_set_drvdata(pdev, info);
301
302	par = info->par;
303
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;
308
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;
319
320	info->apertures = alloc_apertures(1);
321	if (!info->apertures) {
322		ret = -ENOMEM;
323		goto error_fb_release;
324	}
325	info->apertures->ranges[0].base = info->fix.smem_start;
326	info->apertures->ranges[0].size = info->fix.smem_len;
327
328	info->fbops = &simplefb_ops;
329	info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE;
330	info->screen_base = ioremap_wc(info->fix.smem_start,
331				       info->fix.smem_len);
332	if (!info->screen_base) {
333		ret = -ENOMEM;
334		goto error_fb_release;
335	}
336	info->pseudo_palette = par->palette;
337
338	ret = simplefb_clocks_init(par, pdev);
339	if (ret < 0)
340		goto error_unmap;
341
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,
344			     info->screen_base);
345	dev_info(&pdev->dev, "format=%s, mode=%dx%dx%d, linelength=%d\n",
346			     params.format->name,
347			     info->var.xres, info->var.yres,
348			     info->var.bits_per_pixel, info->fix.line_length);
349
350	ret = register_framebuffer(info);
351	if (ret < 0) {
352		dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
353		goto error_clocks;
354	}
355
356	dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node);
357
358	return 0;
359
360error_clocks:
361	simplefb_clocks_destroy(par);
362error_unmap:
363	iounmap(info->screen_base);
364error_fb_release:
365	framebuffer_release(info);
366	return ret;
367}
368
369static int simplefb_remove(struct platform_device *pdev)
370{
371	struct fb_info *info = platform_get_drvdata(pdev);
372	struct simplefb_par *par = info->par;
373
374	unregister_framebuffer(info);
375	simplefb_clocks_destroy(par);
376	framebuffer_release(info);
377
378	return 0;
379}
380
381static const struct of_device_id simplefb_of_match[] = {
382	{ .compatible = "simple-framebuffer", },
383	{ },
384};
385MODULE_DEVICE_TABLE(of, simplefb_of_match);
386
387static struct platform_driver simplefb_driver = {
388	.driver = {
389		.name = "simple-framebuffer",
390		.of_match_table = simplefb_of_match,
391	},
392	.probe = simplefb_probe,
393	.remove = simplefb_remove,
394};
395
396static int __init simplefb_init(void)
397{
398	int ret;
399	struct device_node *np;
400
401	ret = platform_driver_register(&simplefb_driver);
402	if (ret)
403		return ret;
404
405	if (IS_ENABLED(CONFIG_OF_ADDRESS) && 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);
409		}
410	}
411
412	return 0;
413}
414
415fs_initcall(simplefb_init);
416
417MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>");
418MODULE_DESCRIPTION("Simple framebuffer driver");
419MODULE_LICENSE("GPL v2");
420