diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/backlight.h | 59 |
1 files changed, 53 insertions, 6 deletions
diff --git a/include/linux/backlight.h b/include/linux/backlight.h index 56e51ebab740..4ff60774ae22 100644 --- a/include/linux/backlight.h +++ b/include/linux/backlight.h @@ -55,19 +55,66 @@ enum backlight_scale { struct backlight_device; struct fb_info; +/** + * struct backlight_ops - backlight operations + * + * The backlight operations are specified when the backlight device is registered. + */ struct backlight_ops { + /** + * @options: Configure how operations are called from the core. + * + * The options parameter is used to adjust the behaviour of the core. + * Set BL_CORE_SUSPENDRESUME to get the update_status() operation called + * upon suspend and resume. + */ unsigned int options; #define BL_CORE_SUSPENDRESUME (1 << 0) - /* Notify the backlight driver some property has changed */ + /** + * @update_status: Operation called when properties have changed. + * + * Notify the backlight driver some property has changed. + * The update_status operation is protected by the update_lock. + * + * The backlight driver is expected to use backlight_is_blank() + * to check if the display is blanked and set brightness accordingly. + * update_status() is called when any of the properties has changed. + * + * RETURNS: + * + * 0 on success, negative error code if any failure occurred. + */ int (*update_status)(struct backlight_device *); - /* Return the current backlight brightness (accounting for power, - fb_blank etc.) */ + + /** + * @get_brightness: Return the current backlight brightness. + * + * The driver may implement this as a readback from the HW. + * This operation is optional and if not present then the current + * brightness property value is used. + * + * RETURNS: + * + * A brightness value which is 0 or a positive number. + * On failure a negative error code is returned. + */ int (*get_brightness)(struct backlight_device *); - /* Check if given framebuffer device is the one bound to this backlight; - return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */ - int (*check_fb)(struct backlight_device *, struct fb_info *); + + /** + * @check_fb: Check the framebuffer device. + * + * Check if given framebuffer device is the one bound to this backlight. + * This operation is optional and if not implemented it is assumed that the + * fbdev is always the one bound to the backlight. + * + * RETURNS: + * + * If info is NULL or the info matches the fbdev bound to the backlight return true. + * If info does not match the fbdev bound to the backlight return false. + */ + int (*check_fb)(struct backlight_device *bd, struct fb_info *info); }; /* This structure defines all the properties of a backlight */ |