linux/drivers/video/fbdev/core/fbsysfs.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * fbsysfs.c - framebuffer device class and attributes
 *
 * Copyright (c) 2004 James Simmons <jsimmons@infradead.org>
 */

#include <linux/console.h>
#include <linux/fb.h>
#include <linux/fbcon.h>
#include <linux/major.h>

#include "fb_internal.h"

#define FB_SYSFS_FLAG_ATTR 1

static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var)
{
	int err;

	var->activate |= FB_ACTIVATE_FORCE;
	console_lock();
	lock_fb_info(fb_info);
	err = fb_set_var(fb_info, var);
	if (!err)
		fbcon_update_vcs(fb_info, var->activate & FB_ACTIVATE_ALL);
	unlock_fb_info(fb_info);
	console_unlock();
	if (err)
		return err;
	return 0;
}

static int mode_string(char *buf, unsigned int offset,
		       const struct fb_videomode *mode)
{
	char m = 'U';
	char v = 'p';

	if (mode->flag & FB_MODE_IS_DETAILED)
		m = 'D';
	if (mode->flag & FB_MODE_IS_VESA)
		m = 'V';
	if (mode->flag & FB_MODE_IS_STANDARD)
		m = 'S';

	if (mode->vmode & FB_VMODE_INTERLACED)
		v = 'i';
	if (mode->vmode & FB_VMODE_DOUBLE)
		v = 'd';

	return snprintf(&buf[offset], PAGE_SIZE - offset, "%c:%dx%d%c-%d\n",
	                m, mode->xres, mode->yres, v, mode->refresh);
}

static ssize_t store_mode(struct device *device, struct device_attribute *attr,
			  const char *buf, size_t count)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	char mstr[100];
	struct fb_var_screeninfo var;
	struct fb_modelist *modelist;
	struct fb_videomode *mode;
	size_t i;
	int err;

	memset(&var, 0, sizeof(var));

	list_for_each_entry(modelist, &fb_info->modelist, list) {
		mode = &modelist->mode;
		i = mode_string(mstr, 0, mode);
		if (strncmp(mstr, buf, max(count, i)) == 0) {

			var = fb_info->var;
			fb_videomode_to_var(&var, mode);
			if ((err = activate(fb_info, &var)))
				return err;
			fb_info->mode = mode;
			return count;
		}
	}
	return -EINVAL;
}

static ssize_t show_mode(struct device *device, struct device_attribute *attr,
			 char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);

	if (!fb_info->mode)
		return 0;

	return mode_string(buf, 0, fb_info->mode);
}

static ssize_t store_modes(struct device *device,
			   struct device_attribute *attr,
			   const char *buf, size_t count)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	LIST_HEAD(old_list);
	int i = count / sizeof(struct fb_videomode);

	if (i * sizeof(struct fb_videomode) != count)
		return -EINVAL;

	console_lock();
	lock_fb_info(fb_info);

	list_splice(&fb_info->modelist, &old_list);
	fb_videomode_to_modelist((const struct fb_videomode *)buf, i,
				 &fb_info->modelist);
	if (fb_new_modelist(fb_info)) {
		fb_destroy_modelist(&fb_info->modelist);
		list_splice(&old_list, &fb_info->modelist);
	} else
		fb_destroy_modelist(&old_list);

	unlock_fb_info(fb_info);
	console_unlock();

	return 0;
}

static ssize_t show_modes(struct device *device, struct device_attribute *attr,
			  char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	unsigned int i;
	struct fb_modelist *modelist;
	const struct fb_videomode *mode;

	i = 0;
	list_for_each_entry(modelist, &fb_info->modelist, list) {
		mode = &modelist->mode;
		i += mode_string(buf, i, mode);
	}
	return i;
}

static ssize_t store_bpp(struct device *device, struct device_attribute *attr,
			 const char *buf, size_t count)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	struct fb_var_screeninfo var;
	char ** last = NULL;
	int err;

	var = fb_info->var;
	var.bits_per_pixel = simple_strtoul(buf, last, 0);
	if ((err = activate(fb_info, &var)))
		return err;
	return count;
}

static ssize_t show_bpp(struct device *device, struct device_attribute *attr,
			char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	return sysfs_emit(buf, "%d\n", fb_info->var.bits_per_pixel);
}

static ssize_t store_rotate(struct device *device,
			    struct device_attribute *attr,
			    const char *buf, size_t count)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	struct fb_var_screeninfo var;
	char **last = NULL;
	int err;

	var = fb_info->var;
	var.rotate = simple_strtoul(buf, last, 0);

	if ((err = activate(fb_info, &var)))
		return err;

	return count;
}


static ssize_t show_rotate(struct device *device,
			   struct device_attribute *attr, char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);

	return sysfs_emit(buf, "%d\n", fb_info->var.rotate);
}

static ssize_t store_virtual(struct device *device,
			     struct device_attribute *attr,
			     const char *buf, size_t count)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	struct fb_var_screeninfo var;
	char *last = NULL;
	int err;

	var = fb_info->var;
	var.xres_virtual = simple_strtoul(buf, &last, 0);
	last++;
	if (last - buf >= count)
		return -EINVAL;
	var.yres_virtual = simple_strtoul(last, &last, 0);

	if ((err = activate(fb_info, &var)))
		return err;
	return count;
}

static ssize_t show_virtual(struct device *device,
			    struct device_attribute *attr, char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	return sysfs_emit(buf, "%d,%d\n", fb_info->var.xres_virtual,
			fb_info->var.yres_virtual);
}

static ssize_t show_stride(struct device *device,
			   struct device_attribute *attr, char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	return sysfs_emit(buf, "%d\n", fb_info->fix.line_length);
}

static ssize_t store_blank(struct device *device,
			   struct device_attribute *attr,
			   const char *buf, size_t count)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	char *last = NULL;
	int err, arg;

	arg = simple_strtoul(buf, &last, 0);
	console_lock();
	err = fb_blank(fb_info, arg);
	/* might again call into fb_blank */
	fbcon_fb_blanked(fb_info, arg);
	console_unlock();
	if (err < 0)
		return err;
	return count;
}

static ssize_t show_blank(struct device *device, struct device_attribute *attr, char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);

	return sysfs_emit(buf, "%d\n", fb_info->blank);
}

static ssize_t store_console(struct device *device,
			     struct device_attribute *attr,
			     const char *buf, size_t count)
{
//	struct fb_info *fb_info = dev_get_drvdata(device);
	return 0;
}

static ssize_t show_console(struct device *device,
			    struct device_attribute *attr, char *buf)
{
//	struct fb_info *fb_info = dev_get_drvdata(device);
	return 0;
}

static ssize_t store_cursor(struct device *device,
			    struct device_attribute *attr,
			    const char *buf, size_t count)
{
//	struct fb_info *fb_info = dev_get_drvdata(device);
	return 0;
}

static ssize_t show_cursor(struct device *device,
			   struct device_attribute *attr, char *buf)
{
//	struct fb_info *fb_info = dev_get_drvdata(device);
	return 0;
}

static ssize_t store_pan(struct device *device,
			 struct device_attribute *attr,
			 const char *buf, size_t count)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	struct fb_var_screeninfo var;
	char *last = NULL;
	int err;

	var = fb_info->var;
	var.xoffset = simple_strtoul(buf, &last, 0);
	last++;
	if (last - buf >= count)
		return -EINVAL;
	var.yoffset = simple_strtoul(last, &last, 0);

	console_lock();
	err = fb_pan_display(fb_info, &var);
	console_unlock();

	if (err < 0)
		return err;
	return count;
}

static ssize_t show_pan(struct device *device,
			struct device_attribute *attr, char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	return sysfs_emit(buf, "%d,%d\n", fb_info->var.xoffset,
			fb_info->var.yoffset);
}

static ssize_t show_name(struct device *device,
			 struct device_attribute *attr, char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);

	return sysfs_emit(buf, "%s\n", fb_info->fix.id);
}

static ssize_t store_fbstate(struct device *device,
			     struct device_attribute *attr,
			     const char *buf, size_t count)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	u32 state;
	char *last = NULL;

	state = simple_strtoul(buf, &last, 0);

	console_lock();
	lock_fb_info(fb_info);

	fb_set_suspend(fb_info, (int)state);

	unlock_fb_info(fb_info);
	console_unlock();

	return count;
}

static ssize_t show_fbstate(struct device *device,
			    struct device_attribute *attr, char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	return sysfs_emit(buf, "%d\n", fb_info->state);
}

#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
static ssize_t store_bl_curve(struct device *device,
			      struct device_attribute *attr,
			      const char *buf, size_t count)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	u8 tmp_curve[FB_BACKLIGHT_LEVELS];
	unsigned int i;

	/* Some drivers don't use framebuffer_alloc(), but those also
	 * don't have backlights.
	 */
	if (!fb_info || !fb_info->bl_dev)
		return -ENODEV;

	if (count != (FB_BACKLIGHT_LEVELS / 8 * 24))
		return -EINVAL;

	for (i = 0; i < (FB_BACKLIGHT_LEVELS / 8); ++i)
		if (sscanf(&buf[i * 24],
			"%2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx\n",
			&tmp_curve[i * 8 + 0],
			&tmp_curve[i * 8 + 1],
			&tmp_curve[i * 8 + 2],
			&tmp_curve[i * 8 + 3],
			&tmp_curve[i * 8 + 4],
			&tmp_curve[i * 8 + 5],
			&tmp_curve[i * 8 + 6],
			&tmp_curve[i * 8 + 7]) != 8)
			return -EINVAL;

	/* If there has been an error in the input data, we won't
	 * reach this loop.
	 */
	mutex_lock(&fb_info->bl_curve_mutex);
	for (i = 0; i < FB_BACKLIGHT_LEVELS; ++i)
		fb_info->bl_curve[i] = tmp_curve[i];
	mutex_unlock(&fb_info->bl_curve_mutex);

	return count;
}

static ssize_t show_bl_curve(struct device *device,
			     struct device_attribute *attr, char *buf)
{
	struct fb_info *fb_info = dev_get_drvdata(device);
	ssize_t len = 0;
	unsigned int i;

	/* Some drivers don't use framebuffer_alloc(), but those also
	 * don't have backlights.
	 */
	if (!fb_info || !fb_info->bl_dev)
		return -ENODEV;

	mutex_lock(&fb_info->bl_curve_mutex);
	for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8)
		len += scnprintf(&buf[len], PAGE_SIZE - len, "%8ph\n",
				fb_info->bl_curve + i);
	mutex_unlock(&fb_info->bl_curve_mutex);

	return len;
}
#endif

/* When cmap is added back in it should be a binary attribute
 * not a text one. Consideration should also be given to converting
 * fbdev to use configfs instead of sysfs */
static DEVICE_ATTR(bits_per_pixel, 0644, show_bpp, store_bpp);
static DEVICE_ATTR(blank, 0644, show_blank, store_blank);
static DEVICE_ATTR(console, 0644, show_console, store_console);
static DEVICE_ATTR(cursor, 0644, show_cursor, store_cursor);
static DEVICE_ATTR(mode, 0644, show_mode, store_mode);
static DEVICE_ATTR(modes, 0644, show_modes, store_modes);
static DEVICE_ATTR(pan, 0644, show_pan, store_pan);
static DEVICE_ATTR(virtual_size, 0644, show_virtual, store_virtual);
static DEVICE_ATTR(name, 0444, show_name, NULL);
static DEVICE_ATTR(stride, 0444, show_stride, NULL);
static DEVICE_ATTR(rotate, 0644, show_rotate, store_rotate);
static DEVICE_ATTR(state, 0644, show_fbstate, store_fbstate);
#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
static DEVICE_ATTR(bl_curve, 0644, show_bl_curve, store_bl_curve);
#endif

static struct attribute *fb_device_attrs[] = {
	&dev_attr_bits_per_pixel.attr,
	&dev_attr_blank.attr,
	&dev_attr_console.attr,
	&dev_attr_cursor.attr,
	&dev_attr_mode.attr,
	&dev_attr_modes.attr,
	&dev_attr_pan.attr,
	&dev_attr_virtual_size.attr,
	&dev_attr_name.attr,
	&dev_attr_stride.attr,
	&dev_attr_rotate.attr,
	&dev_attr_state.attr,
#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
	&dev_attr_bl_curve.attr,
#endif
	NULL,
};

static const struct attribute_group fb_device_attr_group = {
	.attrs          = fb_device_attrs,
};

static int fb_init_device(struct fb_info *fb_info)
{
	int ret;

	dev_set_drvdata(fb_info->dev, fb_info);

	fb_info->class_flag |= FB_SYSFS_FLAG_ATTR;

	ret = device_add_group(fb_info->dev, &fb_device_attr_group);
	if (ret)
		fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;

	return 0;
}

static void fb_cleanup_device(struct fb_info *fb_info)
{
	if (fb_info->class_flag & FB_SYSFS_FLAG_ATTR) {
		device_remove_group(fb_info->dev, &fb_device_attr_group);

		fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;
	}
}

int fb_device_create(struct fb_info *fb_info)
{
	int node = fb_info->node;
	dev_t devt = MKDEV(FB_MAJOR, node);
	int ret;

	fb_info->dev = device_create(fb_class, fb_info->device, devt, NULL, "fb%d", node);
	if (IS_ERR(fb_info->dev)) {
		/* Not fatal */
		ret = PTR_ERR(fb_info->dev);
		pr_warn("Unable to create device for framebuffer %d; error %d\n", node, ret);
		fb_info->dev = NULL;
	} else {
		fb_init_device(fb_info);
	}

	return 0;
}

void fb_device_destroy(struct fb_info *fb_info)
{
	dev_t devt = MKDEV(FB_MAJOR, fb_info->node);

	if (!fb_info->dev)
		return;

	fb_cleanup_device(fb_info);
	device_destroy(fb_class, devt);
	fb_info->dev = NULL;
}