xref: /linux/drivers/video/fbdev/core/fbsysfs.c (revision b2105aa2c6481fda72c1825800b753a0bf614517)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * fbsysfs.c - framebuffer device class and attributes
4  *
5  * Copyright (c) 2004 James Simmons <jsimmons@infradead.org>
6  */
7 
8 /*
9  * Note:  currently there's only stubs for framebuffer_alloc and
10  * framebuffer_release here.  The reson for that is that until all drivers
11  * are converted to use it a sysfsification will open OOPSable races.
12  */
13 
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/fb.h>
17 #include <linux/fbcon.h>
18 #include <linux/console.h>
19 #include <linux/module.h>
20 
21 #define FB_SYSFS_FLAG_ATTR 1
22 
23 /**
24  * framebuffer_alloc - creates a new frame buffer info structure
25  *
26  * @size: size of driver private data, can be zero
27  * @dev: pointer to the device for this fb, this can be NULL
28  *
29  * Creates a new frame buffer info structure. Also reserves @size bytes
30  * for driver private data (info->par). info->par (if any) will be
31  * aligned to sizeof(long).
32  *
33  * Returns the new structure, or NULL if an error occurred.
34  *
35  */
36 struct fb_info *framebuffer_alloc(size_t size, struct device *dev)
37 {
38 #define BYTES_PER_LONG (BITS_PER_LONG/8)
39 #define PADDING (BYTES_PER_LONG - (sizeof(struct fb_info) % BYTES_PER_LONG))
40 	int fb_info_size = sizeof(struct fb_info);
41 	struct fb_info *info;
42 	char *p;
43 
44 	if (size)
45 		fb_info_size += PADDING;
46 
47 	p = kzalloc(fb_info_size + size, GFP_KERNEL);
48 
49 	if (!p)
50 		return NULL;
51 
52 	info = (struct fb_info *) p;
53 
54 	if (size)
55 		info->par = p + fb_info_size;
56 
57 	info->device = dev;
58 	info->fbcon_rotate_hint = -1;
59 
60 #if IS_ENABLED(CONFIG_FB_BACKLIGHT)
61 	mutex_init(&info->bl_curve_mutex);
62 #endif
63 
64 	return info;
65 #undef PADDING
66 #undef BYTES_PER_LONG
67 }
68 EXPORT_SYMBOL(framebuffer_alloc);
69 
70 /**
71  * framebuffer_release - marks the structure available for freeing
72  *
73  * @info: frame buffer info structure
74  *
75  * Drop the reference count of the device embedded in the
76  * framebuffer info structure.
77  *
78  */
79 void framebuffer_release(struct fb_info *info)
80 {
81 	if (!info)
82 		return;
83 	kfree(info->apertures);
84 	kfree(info);
85 }
86 EXPORT_SYMBOL(framebuffer_release);
87 
88 static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var)
89 {
90 	int err;
91 
92 	var->activate |= FB_ACTIVATE_FORCE;
93 	console_lock();
94 	err = fb_set_var(fb_info, var);
95 	if (!err)
96 		fbcon_update_vcs(fb_info, var->activate & FB_ACTIVATE_ALL);
97 	console_unlock();
98 	if (err)
99 		return err;
100 	return 0;
101 }
102 
103 static int mode_string(char *buf, unsigned int offset,
104 		       const struct fb_videomode *mode)
105 {
106 	char m = 'U';
107 	char v = 'p';
108 
109 	if (mode->flag & FB_MODE_IS_DETAILED)
110 		m = 'D';
111 	if (mode->flag & FB_MODE_IS_VESA)
112 		m = 'V';
113 	if (mode->flag & FB_MODE_IS_STANDARD)
114 		m = 'S';
115 
116 	if (mode->vmode & FB_VMODE_INTERLACED)
117 		v = 'i';
118 	if (mode->vmode & FB_VMODE_DOUBLE)
119 		v = 'd';
120 
121 	return snprintf(&buf[offset], PAGE_SIZE - offset, "%c:%dx%d%c-%d\n",
122 	                m, mode->xres, mode->yres, v, mode->refresh);
123 }
124 
125 static ssize_t store_mode(struct device *device, struct device_attribute *attr,
126 			  const char *buf, size_t count)
127 {
128 	struct fb_info *fb_info = dev_get_drvdata(device);
129 	char mstr[100];
130 	struct fb_var_screeninfo var;
131 	struct fb_modelist *modelist;
132 	struct fb_videomode *mode;
133 	struct list_head *pos;
134 	size_t i;
135 	int err;
136 
137 	memset(&var, 0, sizeof(var));
138 
139 	list_for_each(pos, &fb_info->modelist) {
140 		modelist = list_entry(pos, struct fb_modelist, list);
141 		mode = &modelist->mode;
142 		i = mode_string(mstr, 0, mode);
143 		if (strncmp(mstr, buf, max(count, i)) == 0) {
144 
145 			var = fb_info->var;
146 			fb_videomode_to_var(&var, mode);
147 			if ((err = activate(fb_info, &var)))
148 				return err;
149 			fb_info->mode = mode;
150 			return count;
151 		}
152 	}
153 	return -EINVAL;
154 }
155 
156 static ssize_t show_mode(struct device *device, struct device_attribute *attr,
157 			 char *buf)
158 {
159 	struct fb_info *fb_info = dev_get_drvdata(device);
160 
161 	if (!fb_info->mode)
162 		return 0;
163 
164 	return mode_string(buf, 0, fb_info->mode);
165 }
166 
167 static ssize_t store_modes(struct device *device,
168 			   struct device_attribute *attr,
169 			   const char *buf, size_t count)
170 {
171 	struct fb_info *fb_info = dev_get_drvdata(device);
172 	LIST_HEAD(old_list);
173 	int i = count / sizeof(struct fb_videomode);
174 
175 	if (i * sizeof(struct fb_videomode) != count)
176 		return -EINVAL;
177 
178 	console_lock();
179 	lock_fb_info(fb_info);
180 
181 	list_splice(&fb_info->modelist, &old_list);
182 	fb_videomode_to_modelist((const struct fb_videomode *)buf, i,
183 				 &fb_info->modelist);
184 	if (fb_new_modelist(fb_info)) {
185 		fb_destroy_modelist(&fb_info->modelist);
186 		list_splice(&old_list, &fb_info->modelist);
187 	} else
188 		fb_destroy_modelist(&old_list);
189 
190 	unlock_fb_info(fb_info);
191 	console_unlock();
192 
193 	return 0;
194 }
195 
196 static ssize_t show_modes(struct device *device, struct device_attribute *attr,
197 			  char *buf)
198 {
199 	struct fb_info *fb_info = dev_get_drvdata(device);
200 	unsigned int i;
201 	struct list_head *pos;
202 	struct fb_modelist *modelist;
203 	const struct fb_videomode *mode;
204 
205 	i = 0;
206 	list_for_each(pos, &fb_info->modelist) {
207 		modelist = list_entry(pos, struct fb_modelist, list);
208 		mode = &modelist->mode;
209 		i += mode_string(buf, i, mode);
210 	}
211 	return i;
212 }
213 
214 static ssize_t store_bpp(struct device *device, struct device_attribute *attr,
215 			 const char *buf, size_t count)
216 {
217 	struct fb_info *fb_info = dev_get_drvdata(device);
218 	struct fb_var_screeninfo var;
219 	char ** last = NULL;
220 	int err;
221 
222 	var = fb_info->var;
223 	var.bits_per_pixel = simple_strtoul(buf, last, 0);
224 	if ((err = activate(fb_info, &var)))
225 		return err;
226 	return count;
227 }
228 
229 static ssize_t show_bpp(struct device *device, struct device_attribute *attr,
230 			char *buf)
231 {
232 	struct fb_info *fb_info = dev_get_drvdata(device);
233 	return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->var.bits_per_pixel);
234 }
235 
236 static ssize_t store_rotate(struct device *device,
237 			    struct device_attribute *attr,
238 			    const char *buf, size_t count)
239 {
240 	struct fb_info *fb_info = dev_get_drvdata(device);
241 	struct fb_var_screeninfo var;
242 	char **last = NULL;
243 	int err;
244 
245 	var = fb_info->var;
246 	var.rotate = simple_strtoul(buf, last, 0);
247 
248 	if ((err = activate(fb_info, &var)))
249 		return err;
250 
251 	return count;
252 }
253 
254 
255 static ssize_t show_rotate(struct device *device,
256 			   struct device_attribute *attr, char *buf)
257 {
258 	struct fb_info *fb_info = dev_get_drvdata(device);
259 
260 	return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->var.rotate);
261 }
262 
263 static ssize_t store_virtual(struct device *device,
264 			     struct device_attribute *attr,
265 			     const char *buf, size_t count)
266 {
267 	struct fb_info *fb_info = dev_get_drvdata(device);
268 	struct fb_var_screeninfo var;
269 	char *last = NULL;
270 	int err;
271 
272 	var = fb_info->var;
273 	var.xres_virtual = simple_strtoul(buf, &last, 0);
274 	last++;
275 	if (last - buf >= count)
276 		return -EINVAL;
277 	var.yres_virtual = simple_strtoul(last, &last, 0);
278 
279 	if ((err = activate(fb_info, &var)))
280 		return err;
281 	return count;
282 }
283 
284 static ssize_t show_virtual(struct device *device,
285 			    struct device_attribute *attr, char *buf)
286 {
287 	struct fb_info *fb_info = dev_get_drvdata(device);
288 	return snprintf(buf, PAGE_SIZE, "%d,%d\n", fb_info->var.xres_virtual,
289 			fb_info->var.yres_virtual);
290 }
291 
292 static ssize_t show_stride(struct device *device,
293 			   struct device_attribute *attr, char *buf)
294 {
295 	struct fb_info *fb_info = dev_get_drvdata(device);
296 	return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->fix.line_length);
297 }
298 
299 static ssize_t store_blank(struct device *device,
300 			   struct device_attribute *attr,
301 			   const char *buf, size_t count)
302 {
303 	struct fb_info *fb_info = dev_get_drvdata(device);
304 	char *last = NULL;
305 	int err, arg;
306 
307 	arg = simple_strtoul(buf, &last, 0);
308 	console_lock();
309 	err = fb_blank(fb_info, arg);
310 	/* might again call into fb_blank */
311 	fbcon_fb_blanked(fb_info, arg);
312 	console_unlock();
313 	if (err < 0)
314 		return err;
315 	return count;
316 }
317 
318 static ssize_t show_blank(struct device *device,
319 			  struct device_attribute *attr, char *buf)
320 {
321 //	struct fb_info *fb_info = dev_get_drvdata(device);
322 	return 0;
323 }
324 
325 static ssize_t store_console(struct device *device,
326 			     struct device_attribute *attr,
327 			     const char *buf, size_t count)
328 {
329 //	struct fb_info *fb_info = dev_get_drvdata(device);
330 	return 0;
331 }
332 
333 static ssize_t show_console(struct device *device,
334 			    struct device_attribute *attr, char *buf)
335 {
336 //	struct fb_info *fb_info = dev_get_drvdata(device);
337 	return 0;
338 }
339 
340 static ssize_t store_cursor(struct device *device,
341 			    struct device_attribute *attr,
342 			    const char *buf, size_t count)
343 {
344 //	struct fb_info *fb_info = dev_get_drvdata(device);
345 	return 0;
346 }
347 
348 static ssize_t show_cursor(struct device *device,
349 			   struct device_attribute *attr, char *buf)
350 {
351 //	struct fb_info *fb_info = dev_get_drvdata(device);
352 	return 0;
353 }
354 
355 static ssize_t store_pan(struct device *device,
356 			 struct device_attribute *attr,
357 			 const char *buf, size_t count)
358 {
359 	struct fb_info *fb_info = dev_get_drvdata(device);
360 	struct fb_var_screeninfo var;
361 	char *last = NULL;
362 	int err;
363 
364 	var = fb_info->var;
365 	var.xoffset = simple_strtoul(buf, &last, 0);
366 	last++;
367 	if (last - buf >= count)
368 		return -EINVAL;
369 	var.yoffset = simple_strtoul(last, &last, 0);
370 
371 	console_lock();
372 	err = fb_pan_display(fb_info, &var);
373 	console_unlock();
374 
375 	if (err < 0)
376 		return err;
377 	return count;
378 }
379 
380 static ssize_t show_pan(struct device *device,
381 			struct device_attribute *attr, char *buf)
382 {
383 	struct fb_info *fb_info = dev_get_drvdata(device);
384 	return snprintf(buf, PAGE_SIZE, "%d,%d\n", fb_info->var.xoffset,
385 			fb_info->var.yoffset);
386 }
387 
388 static ssize_t show_name(struct device *device,
389 			 struct device_attribute *attr, char *buf)
390 {
391 	struct fb_info *fb_info = dev_get_drvdata(device);
392 
393 	return snprintf(buf, PAGE_SIZE, "%s\n", fb_info->fix.id);
394 }
395 
396 static ssize_t store_fbstate(struct device *device,
397 			     struct device_attribute *attr,
398 			     const char *buf, size_t count)
399 {
400 	struct fb_info *fb_info = dev_get_drvdata(device);
401 	u32 state;
402 	char *last = NULL;
403 
404 	state = simple_strtoul(buf, &last, 0);
405 
406 	console_lock();
407 	lock_fb_info(fb_info);
408 
409 	fb_set_suspend(fb_info, (int)state);
410 
411 	unlock_fb_info(fb_info);
412 	console_unlock();
413 
414 	return count;
415 }
416 
417 static ssize_t show_fbstate(struct device *device,
418 			    struct device_attribute *attr, char *buf)
419 {
420 	struct fb_info *fb_info = dev_get_drvdata(device);
421 	return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->state);
422 }
423 
424 #if IS_ENABLED(CONFIG_FB_BACKLIGHT)
425 static ssize_t store_bl_curve(struct device *device,
426 			      struct device_attribute *attr,
427 			      const char *buf, size_t count)
428 {
429 	struct fb_info *fb_info = dev_get_drvdata(device);
430 	u8 tmp_curve[FB_BACKLIGHT_LEVELS];
431 	unsigned int i;
432 
433 	/* Some drivers don't use framebuffer_alloc(), but those also
434 	 * don't have backlights.
435 	 */
436 	if (!fb_info || !fb_info->bl_dev)
437 		return -ENODEV;
438 
439 	if (count != (FB_BACKLIGHT_LEVELS / 8 * 24))
440 		return -EINVAL;
441 
442 	for (i = 0; i < (FB_BACKLIGHT_LEVELS / 8); ++i)
443 		if (sscanf(&buf[i * 24],
444 			"%2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx\n",
445 			&tmp_curve[i * 8 + 0],
446 			&tmp_curve[i * 8 + 1],
447 			&tmp_curve[i * 8 + 2],
448 			&tmp_curve[i * 8 + 3],
449 			&tmp_curve[i * 8 + 4],
450 			&tmp_curve[i * 8 + 5],
451 			&tmp_curve[i * 8 + 6],
452 			&tmp_curve[i * 8 + 7]) != 8)
453 			return -EINVAL;
454 
455 	/* If there has been an error in the input data, we won't
456 	 * reach this loop.
457 	 */
458 	mutex_lock(&fb_info->bl_curve_mutex);
459 	for (i = 0; i < FB_BACKLIGHT_LEVELS; ++i)
460 		fb_info->bl_curve[i] = tmp_curve[i];
461 	mutex_unlock(&fb_info->bl_curve_mutex);
462 
463 	return count;
464 }
465 
466 static ssize_t show_bl_curve(struct device *device,
467 			     struct device_attribute *attr, char *buf)
468 {
469 	struct fb_info *fb_info = dev_get_drvdata(device);
470 	ssize_t len = 0;
471 	unsigned int i;
472 
473 	/* Some drivers don't use framebuffer_alloc(), but those also
474 	 * don't have backlights.
475 	 */
476 	if (!fb_info || !fb_info->bl_dev)
477 		return -ENODEV;
478 
479 	mutex_lock(&fb_info->bl_curve_mutex);
480 	for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8)
481 		len += scnprintf(&buf[len], PAGE_SIZE - len, "%8ph\n",
482 				fb_info->bl_curve + i);
483 	mutex_unlock(&fb_info->bl_curve_mutex);
484 
485 	return len;
486 }
487 #endif
488 
489 /* When cmap is added back in it should be a binary attribute
490  * not a text one. Consideration should also be given to converting
491  * fbdev to use configfs instead of sysfs */
492 static struct device_attribute device_attrs[] = {
493 	__ATTR(bits_per_pixel, S_IRUGO|S_IWUSR, show_bpp, store_bpp),
494 	__ATTR(blank, S_IRUGO|S_IWUSR, show_blank, store_blank),
495 	__ATTR(console, S_IRUGO|S_IWUSR, show_console, store_console),
496 	__ATTR(cursor, S_IRUGO|S_IWUSR, show_cursor, store_cursor),
497 	__ATTR(mode, S_IRUGO|S_IWUSR, show_mode, store_mode),
498 	__ATTR(modes, S_IRUGO|S_IWUSR, show_modes, store_modes),
499 	__ATTR(pan, S_IRUGO|S_IWUSR, show_pan, store_pan),
500 	__ATTR(virtual_size, S_IRUGO|S_IWUSR, show_virtual, store_virtual),
501 	__ATTR(name, S_IRUGO, show_name, NULL),
502 	__ATTR(stride, S_IRUGO, show_stride, NULL),
503 	__ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate),
504 	__ATTR(state, S_IRUGO|S_IWUSR, show_fbstate, store_fbstate),
505 #if IS_ENABLED(CONFIG_FB_BACKLIGHT)
506 	__ATTR(bl_curve, S_IRUGO|S_IWUSR, show_bl_curve, store_bl_curve),
507 #endif
508 };
509 
510 int fb_init_device(struct fb_info *fb_info)
511 {
512 	int i, error = 0;
513 
514 	dev_set_drvdata(fb_info->dev, fb_info);
515 
516 	fb_info->class_flag |= FB_SYSFS_FLAG_ATTR;
517 
518 	for (i = 0; i < ARRAY_SIZE(device_attrs); i++) {
519 		error = device_create_file(fb_info->dev, &device_attrs[i]);
520 
521 		if (error)
522 			break;
523 	}
524 
525 	if (error) {
526 		while (--i >= 0)
527 			device_remove_file(fb_info->dev, &device_attrs[i]);
528 		fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;
529 	}
530 
531 	return 0;
532 }
533 
534 void fb_cleanup_device(struct fb_info *fb_info)
535 {
536 	unsigned int i;
537 
538 	if (fb_info->class_flag & FB_SYSFS_FLAG_ATTR) {
539 		for (i = 0; i < ARRAY_SIZE(device_attrs); i++)
540 			device_remove_file(fb_info->dev, &device_attrs[i]);
541 
542 		fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;
543 	}
544 }
545 
546 #if IS_ENABLED(CONFIG_FB_BACKLIGHT)
547 /* This function generates a linear backlight curve
548  *
549  *     0: off
550  *   1-7: min
551  * 8-127: linear from min to max
552  */
553 void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max)
554 {
555 	unsigned int i, flat, count, range = (max - min);
556 
557 	mutex_lock(&fb_info->bl_curve_mutex);
558 
559 	fb_info->bl_curve[0] = off;
560 
561 	for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
562 		fb_info->bl_curve[flat] = min;
563 
564 	count = FB_BACKLIGHT_LEVELS * 15 / 16;
565 	for (i = 0; i < count; ++i)
566 		fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count);
567 
568 	mutex_unlock(&fb_info->bl_curve_mutex);
569 }
570 EXPORT_SYMBOL_GPL(fb_bl_default_curve);
571 #endif
572