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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Simplest possible simple frame-buffer driver, as a platform device
4 *
5 * Copyright (c) 2013, Stephen Warren
6 *
7 * Based on q40fb.c, which was:
8 * Copyright (C) 2001 Richard Zidlicky <[email protected]>
9 *
10 * Also based on offb.c, which was:
11 * Copyright (C) 1997 Geert Uytterhoeven
12 * Copyright (C) 1996 Paul Mackerras
13 */
14
15#include <linux/aperture.h>
16#include <linux/clk.h>
17#include <linux/errno.h>
18#include <linux/fb.h>
19#include <linux/io.h>
20#include <linux/module.h>
21#include <linux/of.h>
22#include <linux/of_clk.h>
23#include <linux/of_platform.h>
24#include <linux/of_reserved_mem.h>
25#include <linux/parser.h>
26#include <linux/platform_data/simplefb.h>
27#include <linux/platform_device.h>
28#include <linux/pm_domain.h>
29#include <linux/regulator/consumer.h>
30
31static const struct fb_fix_screeninfo simplefb_fix = {
32 .id = "simple",
33 .type = FB_TYPE_PACKED_PIXELS,
34 .visual = FB_VISUAL_TRUECOLOR,
35 .accel = FB_ACCEL_NONE,
36};
37
38static const struct fb_var_screeninfo simplefb_var = {
39 .height = -1,
40 .width = -1,
41 .activate = FB_ACTIVATE_NOW,
42 .vmode = FB_VMODE_NONINTERLACED,
43};
44
45#define PSEUDO_PALETTE_SIZE 16
46
47static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
48 u_int transp, struct fb_info *info)
49{
50 u32 *pal = info->pseudo_palette;
51 u32 cr = red >> (16 - info->var.red.length);
52 u32 cg = green >> (16 - info->var.green.length);
53 u32 cb = blue >> (16 - info->var.blue.length);
54 u32 value;
55
56 if (regno >= PSEUDO_PALETTE_SIZE)
57 return -EINVAL;
58
59 value = (cr << info->var.red.offset) |
60 (cg << info->var.green.offset) |
61 (cb << info->var.blue.offset);
62 if (info->var.transp.length > 0) {
63 u32 mask = (1 << info->var.transp.length) - 1;
64 mask <<= info->var.transp.offset;
65 value |= mask;
66 }
67 pal[regno] = value;
68
69 return 0;
70}
71
72struct simplefb_par {
73 u32 palette[PSEUDO_PALETTE_SIZE];
74 resource_size_t base;
75 resource_size_t size;
76 struct resource *mem;
77#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
78 bool clks_enabled;
79 unsigned int clk_count;
80 struct clk **clks;
81#endif
82#if defined CONFIG_OF && defined CONFIG_PM_GENERIC_DOMAINS
83 unsigned int num_genpds;
84 struct device **genpds;
85 struct device_link **genpd_links;
86#endif
87#if defined CONFIG_OF && defined CONFIG_REGULATOR
88 bool regulators_enabled;
89 u32 regulator_count;
90 struct regulator **regulators;
91#endif
92};
93
94static void simplefb_clocks_destroy(struct simplefb_par *par);
95static void simplefb_regulators_destroy(struct simplefb_par *par);
96static void simplefb_detach_genpds(void *res);
97
98/*
99 * fb_ops.fb_destroy is called by the last put_fb_info() call at the end
100 * of unregister_framebuffer() or fb_release(). Do any cleanup here.
101 */
102static void simplefb_destroy(struct fb_info *info)
103{
104 struct simplefb_par *par = info->par;
105 struct resource *mem = par->mem;
106
107 simplefb_regulators_destroy(info->par);
108 simplefb_clocks_destroy(info->par);
109 simplefb_detach_genpds(info->par);
110 if (info->screen_base)
111 iounmap(info->screen_base);
112
113 framebuffer_release(info);
114
115 if (mem)
116 release_mem_region(mem->start, resource_size(mem));
117}
118
119static const struct fb_ops simplefb_ops = {
120 .owner = THIS_MODULE,
121 FB_DEFAULT_IOMEM_OPS,
122 .fb_destroy = simplefb_destroy,
123 .fb_setcolreg = simplefb_setcolreg,
124};
125
126static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS;
127
128struct simplefb_params {
129 u32 width;
130 u32 height;
131 u32 stride;
132 struct simplefb_format *format;
133 struct resource memory;
134};
135
136static int simplefb_parse_dt(struct platform_device *pdev,
137 struct simplefb_params *params)
138{
139 struct device_node *np = pdev->dev.of_node;
140 int ret;
141 const char *format;
142 int i;
143
144 ret = of_property_read_u32(np, "width", &params->width);
145 if (ret) {
146 dev_err(&pdev->dev, "Can't parse width property\n");
147 return ret;
148 }
149
150 ret = of_property_read_u32(np, "height", &params->height);
151 if (ret) {
152 dev_err(&pdev->dev, "Can't parse height property\n");
153 return ret;
154 }
155
156 ret = of_property_read_u32(np, "stride", &params->stride);
157 if (ret) {
158 dev_err(&pdev->dev, "Can't parse stride property\n");
159 return ret;
160 }
161
162 ret = of_property_read_string(np, "format", &format);
163 if (ret) {
164 dev_err(&pdev->dev, "Can't parse format property\n");
165 return ret;
166 }
167 params->format = NULL;
168 for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
169 if (strcmp(format, simplefb_formats[i].name))
170 continue;
171 params->format = &simplefb_formats[i];
172 break;
173 }
174 if (!params->format) {
175 dev_err(&pdev->dev, "Invalid format value\n");
176 return -EINVAL;
177 }
178
179 ret = of_reserved_mem_region_to_resource(np, 0, &params->memory);
180 if (!ret) {
181 if (of_property_present(np, "reg"))
182 dev_warn(&pdev->dev, "preferring \"memory-region\" over \"reg\" property\n");
183 } else {
184 memset(&params->memory, 0, sizeof(params->memory));
185 }
186
187 return 0;
188}
189
190static int simplefb_parse_pd(struct platform_device *pdev,
191 struct simplefb_params *params)
192{
193 struct simplefb_platform_data *pd = dev_get_platdata(&pdev->dev);
194 int i;
195
196 params->width = pd->width;
197 params->height = pd->height;
198 params->stride = pd->stride;
199
200 params->format = NULL;
201 for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
202 if (strcmp(pd->format, simplefb_formats[i].name))
203 continue;
204
205 params->format = &simplefb_formats[i];
206 break;
207 }
208
209 if (!params->format) {
210 dev_err(&pdev->dev, "Invalid format value\n");
211 return -EINVAL;
212 }
213
214 memset(&params->memory, 0, sizeof(params->memory));
215
216 return 0;
217}
218
219#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
220/*
221 * Clock handling code.
222 *
223 * Here we handle the clocks property of our "simple-framebuffer" dt node.
224 * This is necessary so that we can make sure that any clocks needed by
225 * the display engine that the bootloader set up for us (and for which it
226 * provided a simplefb dt node), stay up, for the life of the simplefb
227 * driver.
228 *
229 * When the driver unloads, we cleanly disable, and then release the clocks.
230 *
231 * We only complain about errors here, no action is taken as the most likely
232 * error can only happen due to a mismatch between the bootloader which set
233 * up simplefb, and the clock definitions in the device tree. Chances are
234 * that there are no adverse effects, and if there are, a clean teardown of
235 * the fb probe will not help us much either. So just complain and carry on,
236 * and hope that the user actually gets a working fb at the end of things.
237 */
238static int simplefb_clocks_get(struct simplefb_par *par,
239 struct platform_device *pdev)
240{
241 struct device_node *np = pdev->dev.of_node;
242 struct clk *clock;
243 int i;
244
245 if (dev_get_platdata(&pdev->dev) || !np)
246 return 0;
247
248 par->clk_count = of_clk_get_parent_count(np);
249 if (!par->clk_count)
250 return 0;
251
252 par->clks = kzalloc_objs(struct clk *, par->clk_count);
253 if (!par->clks)
254 return -ENOMEM;
255
256 for (i = 0; i < par->clk_count; i++) {
257 clock = of_clk_get(np, i);
258 if (IS_ERR(clock)) {
259 if (PTR_ERR(clock) == -EPROBE_DEFER) {
260 while (--i >= 0) {
261 clk_put(par->clks[i]);
262 }
263 kfree(par->clks);
264 return -EPROBE_DEFER;
265 }
266 dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
267 __func__, i, PTR_ERR(clock));
268 continue;
269 }
270 par->clks[i] = clock;
271 }
272
273 return 0;
274}
275
276static void simplefb_clocks_enable(struct simplefb_par *par,
277 struct platform_device *pdev)
278{
279 int i, ret;
280
281 for (i = 0; i < par->clk_count; i++) {
282 if (par->clks[i]) {
283 ret = clk_prepare_enable(par->clks[i]);
284 if (ret) {
285 dev_err(&pdev->dev,
286 "%s: failed to enable clock %d: %d\n",
287 __func__, i, ret);
288 clk_put(par->clks[i]);
289 par->clks[i] = NULL;
290 }
291 }
292 }
293 par->clks_enabled = true;
294}
295
296static void simplefb_clocks_destroy(struct simplefb_par *par)
297{
298 int i;
299
300 if (!par->clks)
301 return;
302
303 for (i = 0; i < par->clk_count; i++) {
304 if (par->clks[i]) {
305 if (par->clks_enabled)
306 clk_disable_unprepare(par->clks[i]);
307 clk_put(par->clks[i]);
308 }
309 }
310
311 kfree(par->clks);
312}
313#else
314static int simplefb_clocks_get(struct simplefb_par *par,
315 struct platform_device *pdev) { return 0; }
316static void simplefb_clocks_enable(struct simplefb_par *par,
317 struct platform_device *pdev) { }
318static void simplefb_clocks_destroy(struct simplefb_par *par) { }
319#endif
320
321#if defined CONFIG_OF && defined CONFIG_REGULATOR
322
323#define SUPPLY_SUFFIX "-supply"
324
325/*
326 * Regulator handling code.
327 *
328 * Here we handle the num-supplies and vin*-supply properties of our
329 * "simple-framebuffer" dt node. This is necessary so that we can make sure
330 * that any regulators needed by the display hardware that the bootloader
331 * set up for us (and for which it provided a simplefb dt node), stay up,
332 * for the life of the simplefb driver.
333 *
334 * When the driver unloads, we cleanly disable, and then release the
335 * regulators.
336 *
337 * We only complain about errors here, no action is taken as the most likely
338 * error can only happen due to a mismatch between the bootloader which set
339 * up simplefb, and the regulator definitions in the device tree. Chances are
340 * that there are no adverse effects, and if there are, a clean teardown of
341 * the fb probe will not help us much either. So just complain and carry on,
342 * and hope that the user actually gets a working fb at the end of things.
343 */
344static int simplefb_regulators_get(struct simplefb_par *par,
345 struct platform_device *pdev)
346{
347 struct device_node *np = pdev->dev.of_node;
348 struct property *prop;
349 struct regulator *regulator;
350 const char *p;
351 int count = 0, i = 0;
352
353 if (dev_get_platdata(&pdev->dev) || !np)
354 return 0;
355
356 /* Count the number of regulator supplies */
357 for_each_property_of_node(np, prop) {
358 p = strstr(prop->name, SUPPLY_SUFFIX);
359 if (p && p != prop->name)
360 count++;
361 }
362
363 if (!count)
364 return 0;
365
366 par->regulators = devm_kcalloc(&pdev->dev, count,
367 sizeof(struct regulator *), GFP_KERNEL);
368 if (!par->regulators)
369 return -ENOMEM;
370
371 /* Get all the regulators */
372 for_each_property_of_node(np, prop) {
373 char name[32]; /* 32 is max size of property name */
374
375 p = strstr(prop->name, SUPPLY_SUFFIX);
376 if (!p || p == prop->name)
377 continue;
378
379 strscpy(name, prop->name,
380 strlen(prop->name) - strlen(SUPPLY_SUFFIX) + 1);
381 regulator = devm_regulator_get_optional(&pdev->dev, name);
382 if (IS_ERR(regulator)) {
383 if (PTR_ERR(regulator) == -EPROBE_DEFER)
384 return -EPROBE_DEFER;
385 dev_err(&pdev->dev, "regulator %s not found: %ld\n",
386 name, PTR_ERR(regulator));
387 continue;
388 }
389 par->regulators[i++] = regulator;
390 }
391 par->regulator_count = i;
392
393 return 0;
394}
395
396static void simplefb_regulators_enable(struct simplefb_par *par,
397 struct platform_device *pdev)
398{
399 int i, ret;
400
401 /* Enable all the regulators */
402 for (i = 0; i < par->regulator_count; i++) {
403 ret = regulator_enable(par->regulators[i]);
404 if (ret) {
405 dev_err(&pdev->dev,
406 "failed to enable regulator %d: %d\n",
407 i, ret);
408 devm_regulator_put(par->regulators[i]);
409 par->regulators[i] = NULL;
410 }
411 }
412 par->regulators_enabled = true;
413}
414
415static void simplefb_regulators_destroy(struct simplefb_par *par)
416{
417 int i;
418
419 if (!par->regulators || !par->regulators_enabled)
420 return;
421
422 for (i = 0; i < par->regulator_count; i++)
423 if (par->regulators[i])
424 regulator_disable(par->regulators[i]);
425}
426#else
427static int simplefb_regulators_get(struct simplefb_par *par,
428 struct platform_device *pdev) { return 0; }
429static void simplefb_regulators_enable(struct simplefb_par *par,
430 struct platform_device *pdev) { }
431static void simplefb_regulators_destroy(struct simplefb_par *par) { }
432#endif
433
434#if defined CONFIG_OF && defined CONFIG_PM_GENERIC_DOMAINS
435static void simplefb_detach_genpds(void *res)
436{
437 struct simplefb_par *par = res;
438 unsigned int i = par->num_genpds;
439
440 if (par->num_genpds <= 1)
441 return;
442
443 while (i--) {
444 if (par->genpd_links[i])
445 device_link_del(par->genpd_links[i]);
446
447 if (!IS_ERR_OR_NULL(par->genpds[i]))
448 dev_pm_domain_detach(par->genpds[i], true);
449 }
450 par->num_genpds = 0;
451}
452
453static int simplefb_attach_genpds(struct simplefb_par *par,
454 struct platform_device *pdev)
455{
456 struct device *dev = &pdev->dev;
457 unsigned int i, num_genpds;
458 int err;
459
460 err = of_count_phandle_with_args(dev->of_node, "power-domains",
461 "#power-domain-cells");
462 if (err < 0) {
463 /* Nothing wrong if optional PDs are missing */
464 if (err == -ENOENT)
465 return 0;
466
467 dev_err(dev, "failed to parse power-domains: %d\n", err);
468 return err;
469 }
470
471 num_genpds = err;
472
473 /*
474 * Single power-domain devices are handled by the driver core, so
475 * nothing to do here.
476 */
477 if (num_genpds <= 1) {
478 par->num_genpds = num_genpds;
479 return 0;
480 }
481
482 par->genpds = devm_kcalloc(dev, num_genpds, sizeof(*par->genpds),
483 GFP_KERNEL);
484 if (!par->genpds)
485 return -ENOMEM;
486
487 par->genpd_links = devm_kcalloc(dev, num_genpds,
488 sizeof(*par->genpd_links),
489 GFP_KERNEL);
490 if (!par->genpd_links)
491 return -ENOMEM;
492
493 /*
494 * Set par->num_genpds only after genpds and genpd_links are allocated
495 * to exit early from simplefb_detach_genpds() without full
496 * initialisation.
497 */
498 par->num_genpds = num_genpds;
499
500 for (i = 0; i < par->num_genpds; i++) {
501 par->genpds[i] = dev_pm_domain_attach_by_id(dev, i);
502 if (IS_ERR(par->genpds[i])) {
503 err = PTR_ERR(par->genpds[i]);
504 if (err == -EPROBE_DEFER) {
505 simplefb_detach_genpds(par);
506 return err;
507 }
508
509 dev_warn(dev, "failed to attach domain %u: %d\n", i, err);
510 continue;
511 }
512
513 par->genpd_links[i] = device_link_add(dev, par->genpds[i],
514 DL_FLAG_STATELESS |
515 DL_FLAG_PM_RUNTIME |
516 DL_FLAG_RPM_ACTIVE);
517 if (!par->genpd_links[i])
518 dev_warn(dev, "failed to link power-domain %u\n", i);
519 }
520
521 return 0;
522}
523#else
524static void simplefb_detach_genpds(void *res) { }
525static int simplefb_attach_genpds(struct simplefb_par *par,
526 struct platform_device *pdev)
527{
528 return 0;
529}
530#endif
531
532static int simplefb_probe(struct platform_device *pdev)
533{
534 int ret;
535 struct simplefb_params params;
536 struct fb_info *info;
537 struct simplefb_par *par;
538 struct resource *res, *mem;
539
540 if (fb_get_options("simplefb", NULL))
541 return -ENODEV;
542
543 ret = -ENODEV;
544 if (dev_get_platdata(&pdev->dev))
545 ret = simplefb_parse_pd(pdev, &params);
546 else if (pdev->dev.of_node)
547 ret = simplefb_parse_dt(pdev, &params);
548
549 if (ret)
550 return ret;
551
552 if (params.memory.start == 0 && params.memory.end == 0) {
553 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
554 if (!res) {
555 dev_err(&pdev->dev, "No memory resource\n");
556 return -EINVAL;
557 }
558 } else {
559 res = &params.memory;
560 }
561
562 mem = request_mem_region(res->start, resource_size(res), "simplefb");
563 if (!mem) {
564 /*
565 * We cannot make this fatal. Sometimes this comes from magic
566 * spaces our resource handlers simply don't know about. Use
567 * the I/O-memory resource as-is and try to map that instead.
568 */
569 dev_warn(&pdev->dev, "simplefb: cannot reserve video memory at %pR\n", res);
570 mem = res;
571 }
572
573 info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
574 if (!info) {
575 ret = -ENOMEM;
576 goto error_release_mem_region;
577 }
578 platform_set_drvdata(pdev, info);
579
580 par = info->par;
581
582 info->fix = simplefb_fix;
583 info->fix.smem_start = mem->start;
584 info->fix.smem_len = resource_size(mem);
585 info->fix.line_length = params.stride;
586
587 info->var = simplefb_var;
588 info->var.xres = params.width;
589 info->var.yres = params.height;
590 info->var.xres_virtual = params.width;
591 info->var.yres_virtual = params.height;
592 info->var.bits_per_pixel = params.format->bits_per_pixel;
593 info->var.red = params.format->red;
594 info->var.green = params.format->green;
595 info->var.blue = params.format->blue;
596 info->var.transp = params.format->transp;
597
598 par->base = info->fix.smem_start;
599 par->size = info->fix.smem_len;
600
601 info->fbops = &simplefb_ops;
602 info->screen_base = ioremap_wc(info->fix.smem_start,
603 info->fix.smem_len);
604 if (!info->screen_base) {
605 ret = -ENOMEM;
606 goto error_fb_release;
607 }
608 info->pseudo_palette = par->palette;
609
610 ret = simplefb_clocks_get(par, pdev);
611 if (ret < 0)
612 goto error_unmap;
613
614 ret = simplefb_regulators_get(par, pdev);
615 if (ret < 0)
616 goto error_clocks;
617
618 ret = simplefb_attach_genpds(par, pdev);
619 if (ret < 0)
620 goto error_regulators;
621
622 simplefb_clocks_enable(par, pdev);
623 simplefb_regulators_enable(par, pdev);
624
625 dev_info(&pdev->dev, "framebuffer at 0x%lx, 0x%x bytes\n",
626 info->fix.smem_start, info->fix.smem_len);
627 dev_info(&pdev->dev, "format=%s, mode=%dx%dx%d, linelength=%d\n",
628 params.format->name,
629 info->var.xres, info->var.yres,
630 info->var.bits_per_pixel, info->fix.line_length);
631
632 if (mem != res)
633 par->mem = mem; /* release in clean-up handler */
634
635 ret = devm_aperture_acquire_for_platform_device(pdev, par->base, par->size);
636 if (ret) {
637 dev_err(&pdev->dev, "Unable to acquire aperture: %d\n", ret);
638 goto error_genpds;
639 }
640 ret = register_framebuffer(info);
641 if (ret < 0) {
642 dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
643 goto error_genpds;
644 }
645
646 dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node);
647
648 return 0;
649
650error_genpds:
651 simplefb_detach_genpds(par);
652error_regulators:
653 simplefb_regulators_destroy(par);
654error_clocks:
655 simplefb_clocks_destroy(par);
656error_unmap:
657 iounmap(info->screen_base);
658error_fb_release:
659 framebuffer_release(info);
660error_release_mem_region:
661 if (mem != res)
662 release_mem_region(mem->start, resource_size(mem));
663 return ret;
664}
665
666static void simplefb_remove(struct platform_device *pdev)
667{
668 struct fb_info *info = platform_get_drvdata(pdev);
669
670 /* simplefb_destroy takes care of info cleanup */
671 unregister_framebuffer(info);
672}
673
674static const struct of_device_id simplefb_of_match[] = {
675 { .compatible = "simple-framebuffer", },
676 { },
677};
678MODULE_DEVICE_TABLE(of, simplefb_of_match);
679
680static struct platform_driver simplefb_driver = {
681 .driver = {
682 .name = "simple-framebuffer",
683 .of_match_table = simplefb_of_match,
684 },
685 .probe = simplefb_probe,
686 .remove = simplefb_remove,
687};
688
689module_platform_driver(simplefb_driver);
690
691MODULE_AUTHOR("Stephen Warren <[email protected]>");
692MODULE_DESCRIPTION("Simple framebuffer driver");
693MODULE_LICENSE("GPL v2");