backlight: Propagate errors from get_brightness()

backlight.h documents "struct backlight_ops->get_brightness()" to return
a negative errno on failure.

So far these errors have not been handled in the backlight core.
This leads to negative values being exposed through sysfs although only
positive values are documented to be reported.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Thomas Weißschuh 2021-09-07 14:47:51 +02:00 committed by Lee Jones
parent 33a5471f8d
commit 563edf85ce

View file

@ -292,10 +292,13 @@ static ssize_t actual_brightness_show(struct device *dev,
struct backlight_device *bd = to_backlight_device(dev);
mutex_lock(&bd->ops_lock);
if (bd->ops && bd->ops->get_brightness)
rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
else
if (bd->ops && bd->ops->get_brightness) {
rc = bd->ops->get_brightness(bd);
if (rc >= 0)
rc = sprintf(buf, "%d\n", rc);
} else {
rc = sprintf(buf, "%d\n", bd->props.brightness);
}
mutex_unlock(&bd->ops_lock);
return rc;
@ -381,9 +384,18 @@ ATTRIBUTE_GROUPS(bl_device);
void backlight_force_update(struct backlight_device *bd,
enum backlight_update_reason reason)
{
int brightness;
mutex_lock(&bd->ops_lock);
if (bd->ops && bd->ops->get_brightness)
bd->props.brightness = bd->ops->get_brightness(bd);
if (bd->ops && bd->ops->get_brightness) {
brightness = bd->ops->get_brightness(bd);
if (brightness >= 0)
bd->props.brightness = brightness;
else
dev_err(&bd->dev,
"Could not update brightness from device: %pe\n",
ERR_PTR(brightness));
}
mutex_unlock(&bd->ops_lock);
backlight_generate_event(bd, reason);
}