1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * fbsysfs.c - framebuffer device class and attributes
5 * Copyright (c) 2004 James Simmons <jsimmons@infradead.org>
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.
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
17 #include <linux/fbcon.h>
18 #include <linux/console.h>
19 #include <linux/module.h>
21 #define FB_SYSFS_FLAG_ATTR 1
24 * framebuffer_alloc - creates a new frame buffer info structure
26 * @size: size of driver private data, can be zero
27 * @dev: pointer to the device for this fb, this can be NULL
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).
33 * Returns the new structure, or NULL if an error occurred.
36 struct fb_info *framebuffer_alloc(size_t size, struct device *dev)
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);
45 fb_info_size += PADDING;
47 p = kzalloc(fb_info_size + size, GFP_KERNEL);
52 info = (struct fb_info *) p;
55 info->par = p + fb_info_size;
58 info->fbcon_rotate_hint = -1;
60 #if IS_ENABLED(CONFIG_FB_BACKLIGHT)
61 mutex_init(&info->bl_curve_mutex);
68 EXPORT_SYMBOL(framebuffer_alloc);
71 * framebuffer_release - marks the structure available for freeing
73 * @info: frame buffer info structure
75 * Drop the reference count of the device embedded in the
76 * framebuffer info structure.
79 void framebuffer_release(struct fb_info *info)
84 if (WARN_ON(refcount_read(&info->count)))
87 #if IS_ENABLED(CONFIG_FB_BACKLIGHT)
88 mutex_destroy(&info->bl_curve_mutex);
91 kfree(info->apertures);
94 EXPORT_SYMBOL(framebuffer_release);
96 static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var)
100 var->activate |= FB_ACTIVATE_FORCE;
102 lock_fb_info(fb_info);
103 err = fb_set_var(fb_info, var);
105 fbcon_update_vcs(fb_info, var->activate & FB_ACTIVATE_ALL);
106 unlock_fb_info(fb_info);
113 static int mode_string(char *buf, unsigned int offset,
114 const struct fb_videomode *mode)
119 if (mode->flag & FB_MODE_IS_DETAILED)
121 if (mode->flag & FB_MODE_IS_VESA)
123 if (mode->flag & FB_MODE_IS_STANDARD)
126 if (mode->vmode & FB_VMODE_INTERLACED)
128 if (mode->vmode & FB_VMODE_DOUBLE)
131 return snprintf(&buf[offset], PAGE_SIZE - offset, "%c:%dx%d%c-%d\n",
132 m, mode->xres, mode->yres, v, mode->refresh);
135 static ssize_t store_mode(struct device *device, struct device_attribute *attr,
136 const char *buf, size_t count)
138 struct fb_info *fb_info = dev_get_drvdata(device);
140 struct fb_var_screeninfo var;
141 struct fb_modelist *modelist;
142 struct fb_videomode *mode;
143 struct list_head *pos;
147 memset(&var, 0, sizeof(var));
149 list_for_each(pos, &fb_info->modelist) {
150 modelist = list_entry(pos, struct fb_modelist, list);
151 mode = &modelist->mode;
152 i = mode_string(mstr, 0, mode);
153 if (strncmp(mstr, buf, max(count, i)) == 0) {
156 fb_videomode_to_var(&var, mode);
157 if ((err = activate(fb_info, &var)))
159 fb_info->mode = mode;
166 static ssize_t show_mode(struct device *device, struct device_attribute *attr,
169 struct fb_info *fb_info = dev_get_drvdata(device);
174 return mode_string(buf, 0, fb_info->mode);
177 static ssize_t store_modes(struct device *device,
178 struct device_attribute *attr,
179 const char *buf, size_t count)
181 struct fb_info *fb_info = dev_get_drvdata(device);
183 int i = count / sizeof(struct fb_videomode);
185 if (i * sizeof(struct fb_videomode) != count)
189 lock_fb_info(fb_info);
191 list_splice(&fb_info->modelist, &old_list);
192 fb_videomode_to_modelist((const struct fb_videomode *)buf, i,
194 if (fb_new_modelist(fb_info)) {
195 fb_destroy_modelist(&fb_info->modelist);
196 list_splice(&old_list, &fb_info->modelist);
198 fb_destroy_modelist(&old_list);
200 unlock_fb_info(fb_info);
206 static ssize_t show_modes(struct device *device, struct device_attribute *attr,
209 struct fb_info *fb_info = dev_get_drvdata(device);
211 struct list_head *pos;
212 struct fb_modelist *modelist;
213 const struct fb_videomode *mode;
216 list_for_each(pos, &fb_info->modelist) {
217 modelist = list_entry(pos, struct fb_modelist, list);
218 mode = &modelist->mode;
219 i += mode_string(buf, i, mode);
224 static ssize_t store_bpp(struct device *device, struct device_attribute *attr,
225 const char *buf, size_t count)
227 struct fb_info *fb_info = dev_get_drvdata(device);
228 struct fb_var_screeninfo var;
233 var.bits_per_pixel = simple_strtoul(buf, last, 0);
234 if ((err = activate(fb_info, &var)))
239 static ssize_t show_bpp(struct device *device, struct device_attribute *attr,
242 struct fb_info *fb_info = dev_get_drvdata(device);
243 return sysfs_emit(buf, "%d\n", fb_info->var.bits_per_pixel);
246 static ssize_t store_rotate(struct device *device,
247 struct device_attribute *attr,
248 const char *buf, size_t count)
250 struct fb_info *fb_info = dev_get_drvdata(device);
251 struct fb_var_screeninfo var;
256 var.rotate = simple_strtoul(buf, last, 0);
258 if ((err = activate(fb_info, &var)))
265 static ssize_t show_rotate(struct device *device,
266 struct device_attribute *attr, char *buf)
268 struct fb_info *fb_info = dev_get_drvdata(device);
270 return sysfs_emit(buf, "%d\n", fb_info->var.rotate);
273 static ssize_t store_virtual(struct device *device,
274 struct device_attribute *attr,
275 const char *buf, size_t count)
277 struct fb_info *fb_info = dev_get_drvdata(device);
278 struct fb_var_screeninfo var;
283 var.xres_virtual = simple_strtoul(buf, &last, 0);
285 if (last - buf >= count)
287 var.yres_virtual = simple_strtoul(last, &last, 0);
289 if ((err = activate(fb_info, &var)))
294 static ssize_t show_virtual(struct device *device,
295 struct device_attribute *attr, char *buf)
297 struct fb_info *fb_info = dev_get_drvdata(device);
298 return sysfs_emit(buf, "%d,%d\n", fb_info->var.xres_virtual,
299 fb_info->var.yres_virtual);
302 static ssize_t show_stride(struct device *device,
303 struct device_attribute *attr, char *buf)
305 struct fb_info *fb_info = dev_get_drvdata(device);
306 return sysfs_emit(buf, "%d\n", fb_info->fix.line_length);
309 static ssize_t store_blank(struct device *device,
310 struct device_attribute *attr,
311 const char *buf, size_t count)
313 struct fb_info *fb_info = dev_get_drvdata(device);
317 arg = simple_strtoul(buf, &last, 0);
319 err = fb_blank(fb_info, arg);
320 /* might again call into fb_blank */
321 fbcon_fb_blanked(fb_info, arg);
328 static ssize_t show_blank(struct device *device,
329 struct device_attribute *attr, char *buf)
331 // struct fb_info *fb_info = dev_get_drvdata(device);
335 static ssize_t store_console(struct device *device,
336 struct device_attribute *attr,
337 const char *buf, size_t count)
339 // struct fb_info *fb_info = dev_get_drvdata(device);
343 static ssize_t show_console(struct device *device,
344 struct device_attribute *attr, char *buf)
346 // struct fb_info *fb_info = dev_get_drvdata(device);
350 static ssize_t store_cursor(struct device *device,
351 struct device_attribute *attr,
352 const char *buf, size_t count)
354 // struct fb_info *fb_info = dev_get_drvdata(device);
358 static ssize_t show_cursor(struct device *device,
359 struct device_attribute *attr, char *buf)
361 // struct fb_info *fb_info = dev_get_drvdata(device);
365 static ssize_t store_pan(struct device *device,
366 struct device_attribute *attr,
367 const char *buf, size_t count)
369 struct fb_info *fb_info = dev_get_drvdata(device);
370 struct fb_var_screeninfo var;
375 var.xoffset = simple_strtoul(buf, &last, 0);
377 if (last - buf >= count)
379 var.yoffset = simple_strtoul(last, &last, 0);
382 err = fb_pan_display(fb_info, &var);
390 static ssize_t show_pan(struct device *device,
391 struct device_attribute *attr, char *buf)
393 struct fb_info *fb_info = dev_get_drvdata(device);
394 return sysfs_emit(buf, "%d,%d\n", fb_info->var.xoffset,
395 fb_info->var.yoffset);
398 static ssize_t show_name(struct device *device,
399 struct device_attribute *attr, char *buf)
401 struct fb_info *fb_info = dev_get_drvdata(device);
403 return sysfs_emit(buf, "%s\n", fb_info->fix.id);
406 static ssize_t store_fbstate(struct device *device,
407 struct device_attribute *attr,
408 const char *buf, size_t count)
410 struct fb_info *fb_info = dev_get_drvdata(device);
414 state = simple_strtoul(buf, &last, 0);
417 lock_fb_info(fb_info);
419 fb_set_suspend(fb_info, (int)state);
421 unlock_fb_info(fb_info);
427 static ssize_t show_fbstate(struct device *device,
428 struct device_attribute *attr, char *buf)
430 struct fb_info *fb_info = dev_get_drvdata(device);
431 return sysfs_emit(buf, "%d\n", fb_info->state);
434 #if IS_ENABLED(CONFIG_FB_BACKLIGHT)
435 static ssize_t store_bl_curve(struct device *device,
436 struct device_attribute *attr,
437 const char *buf, size_t count)
439 struct fb_info *fb_info = dev_get_drvdata(device);
440 u8 tmp_curve[FB_BACKLIGHT_LEVELS];
443 /* Some drivers don't use framebuffer_alloc(), but those also
444 * don't have backlights.
446 if (!fb_info || !fb_info->bl_dev)
449 if (count != (FB_BACKLIGHT_LEVELS / 8 * 24))
452 for (i = 0; i < (FB_BACKLIGHT_LEVELS / 8); ++i)
453 if (sscanf(&buf[i * 24],
454 "%2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx\n",
455 &tmp_curve[i * 8 + 0],
456 &tmp_curve[i * 8 + 1],
457 &tmp_curve[i * 8 + 2],
458 &tmp_curve[i * 8 + 3],
459 &tmp_curve[i * 8 + 4],
460 &tmp_curve[i * 8 + 5],
461 &tmp_curve[i * 8 + 6],
462 &tmp_curve[i * 8 + 7]) != 8)
465 /* If there has been an error in the input data, we won't
468 mutex_lock(&fb_info->bl_curve_mutex);
469 for (i = 0; i < FB_BACKLIGHT_LEVELS; ++i)
470 fb_info->bl_curve[i] = tmp_curve[i];
471 mutex_unlock(&fb_info->bl_curve_mutex);
476 static ssize_t show_bl_curve(struct device *device,
477 struct device_attribute *attr, char *buf)
479 struct fb_info *fb_info = dev_get_drvdata(device);
483 /* Some drivers don't use framebuffer_alloc(), but those also
484 * don't have backlights.
486 if (!fb_info || !fb_info->bl_dev)
489 mutex_lock(&fb_info->bl_curve_mutex);
490 for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8)
491 len += scnprintf(&buf[len], PAGE_SIZE - len, "%8ph\n",
492 fb_info->bl_curve + i);
493 mutex_unlock(&fb_info->bl_curve_mutex);
499 /* When cmap is added back in it should be a binary attribute
500 * not a text one. Consideration should also be given to converting
501 * fbdev to use configfs instead of sysfs */
502 static struct device_attribute device_attrs[] = {
503 __ATTR(bits_per_pixel, S_IRUGO|S_IWUSR, show_bpp, store_bpp),
504 __ATTR(blank, S_IRUGO|S_IWUSR, show_blank, store_blank),
505 __ATTR(console, S_IRUGO|S_IWUSR, show_console, store_console),
506 __ATTR(cursor, S_IRUGO|S_IWUSR, show_cursor, store_cursor),
507 __ATTR(mode, S_IRUGO|S_IWUSR, show_mode, store_mode),
508 __ATTR(modes, S_IRUGO|S_IWUSR, show_modes, store_modes),
509 __ATTR(pan, S_IRUGO|S_IWUSR, show_pan, store_pan),
510 __ATTR(virtual_size, S_IRUGO|S_IWUSR, show_virtual, store_virtual),
511 __ATTR(name, S_IRUGO, show_name, NULL),
512 __ATTR(stride, S_IRUGO, show_stride, NULL),
513 __ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate),
514 __ATTR(state, S_IRUGO|S_IWUSR, show_fbstate, store_fbstate),
515 #if IS_ENABLED(CONFIG_FB_BACKLIGHT)
516 __ATTR(bl_curve, S_IRUGO|S_IWUSR, show_bl_curve, store_bl_curve),
520 int fb_init_device(struct fb_info *fb_info)
524 dev_set_drvdata(fb_info->dev, fb_info);
526 fb_info->class_flag |= FB_SYSFS_FLAG_ATTR;
528 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) {
529 error = device_create_file(fb_info->dev, &device_attrs[i]);
537 device_remove_file(fb_info->dev, &device_attrs[i]);
538 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;
544 void fb_cleanup_device(struct fb_info *fb_info)
548 if (fb_info->class_flag & FB_SYSFS_FLAG_ATTR) {
549 for (i = 0; i < ARRAY_SIZE(device_attrs); i++)
550 device_remove_file(fb_info->dev, &device_attrs[i]);
552 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;
556 #if IS_ENABLED(CONFIG_FB_BACKLIGHT)
557 /* This function generates a linear backlight curve
561 * 8-127: linear from min to max
563 void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max)
565 unsigned int i, flat, count, range = (max - min);
567 mutex_lock(&fb_info->bl_curve_mutex);
569 fb_info->bl_curve[0] = off;
571 for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
572 fb_info->bl_curve[flat] = min;
574 count = FB_BACKLIGHT_LEVELS * 15 / 16;
575 for (i = 0; i < count; ++i)
576 fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count);
578 mutex_unlock(&fb_info->bl_curve_mutex);
580 EXPORT_SYMBOL_GPL(fb_bl_default_curve);