Improve the documentation for backlight_properties and
adapt it to kernel-doc style.
Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Lee Jones <lee.jones@xxxxxxxxxx>
Cc: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Cc: Jingoo Han <jingoohan1@xxxxxxxxx>
---
include/linux/backlight.h | 101 +++++++++++++++++++++++++++++++++-----
1 file changed, 90 insertions(+), 11 deletions(-)
diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index 519dc61ce7e4..7f9cef299d6e 100644
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -118,28 +118,107 @@ struct backlight_ops {
int (*check_fb)(struct backlight_device *bd, struct fb_info *info);
};
-/* This structure defines all the properties of a backlight */
+/**
+ * struct backlight_properties - backlight properties
+ *
+ * This structure defines all the properties of a backlight.
+ */
struct backlight_properties {
- /* Current User requested brightness (0 - max_brightness) */
+ /**
+ * @brightness:
+ *
+ * The current requested brightness by the user.
+ * The backlight core makes sure the range is (0 - max_brightness)
+ * when the brightness is set via the sysfs attribute:
+ * /sys/class/backlight/<backlight>/brightness.
+ *
+ * This value can be set in the backlight_properties passed
+ * to devm_backlight_device_register() to set a default brightness
+ * value.
+ */
int brightness;
- /* Maximal value for brightness (read-only) */
+
+ /**
+ * @max_brightness:
+ *
+ * The maximum brightness value.
+ *
+ * This value must be set in the backlight_properties passed
+ * to devm_backlight_device_register().
+ *
+ * This property must not be modified by a driver except
+ * before registering the backlight device as explained above.
+ */
int max_brightness;
- /* Current FB Power mode (0: full on, 1..3: power saving
- modes; 4: full off), see FB_BLANK_XXX */
+
+ /**
+ * @power:
+ *
+ * The current power mode. User space configure the power mode using
+ * the sysfs attribute: /sys/class/backlight/<backlight>/bl_power
+ * When the power property is updated update_status() is called.
+ *
+ * The possible values are: (0: full on, 1..3: power saving
+ * modes; 4: full off), see FB_BLANK_XXX.
+ *
+ * When the backlight device is enabled @power is set
+ * to FB_BLANK_UNBLANK. When the backlight device is disabled
+ * @power is set to FB_BLANK_POWERDOWN.
+ */
int power;
- /* FB Blanking active? (values as for power) */
- /* Due to be removed, please use (state & BL_CORE_FBBLANK) */
+
+ /**
+ * @fb_blank:
+ *
+ * When the FBIOBLANK ioctl is called fb_blank is set to the
+ * blank parameter and the update_status() operation is called.
+ *
+ * When the backlight device is enabled @fb_blank is set
+ * to FB_BLANK_UNBLANK. When the backlight device is disabled
+ * @fb_blank is set to FB_BLANK_POWERDOWN.
+ *
+ * This property must not be modified by a driver.
+ * The backlight driver shall never read this variable,
+ * as the necessary info is avaialble via the state.
+ *
+ * fb_blank is deprecated and will be removed.
+ */
int fb_blank;
- /* Backlight type */
+
+ /**
+ * @type:
+ *
+ * The type of backlight supported.
+ * The backlight type allows userspace to make appropriate
+ * policy desicions based on the backlight type.
+ *
+ * This value must be set in the backlight_properties
+ * passed to devm_backlight_device_register().
+ */
enum backlight_type type;
- /* Flags used to signal drivers of state changes */
+
+ /**
+ * @state:
+ *
+ * The state property is used to inform drivers of state changes
+ * when the update_status() operation is called.
+ * The state is a bitmask. BL_CORE_FBBLANK is set when the display
+ * is expected to be blank. BL_CORE_SUSPENDED is set when the
+ * driver is suspended.
+ *
+ * This property must not be modified by a driver.
+ */
unsigned int state;
- /* Type of the brightness scale (linear, non-linear, ...) */
- enum backlight_scale scale;
#define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */
#define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */
+ /**
+ * @scale:
+ *
+ * The type of the brightness scale (linear, non-linear, ...)
+ */
+ enum backlight_scale scale;
};
struct backlight_device {
--
2.25.1
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