drm/radeon: rework legacy backlight control

To better enable sharing with atom backlight control.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_legacy_encoders.c

@@ -271,13 +271,6 @@ static const struct drm_encoder_helper_funcs radeon_legacy_lvds_helper_funcs = {
 
 #if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
 
-#define MAX_RADEON_LEVEL 0xFF
-
-struct radeon_backlight_privdata {
-	struct radeon_encoder *encoder;
-	uint8_t negative;
-};
-
 static uint8_t radeon_legacy_lvds_level(struct backlight_device *bd)
 {
 	struct radeon_backlight_privdata *pdata = bl_get_data(bd);
@@ -286,13 +279,13 @@ static uint8_t radeon_legacy_lvds_level(struct backlight_device *bd)
 	/* Convert brightness to hardware level */
 	if (bd->props.brightness < 0)
 		level = 0;
-	else if (bd->props.brightness > MAX_RADEON_LEVEL)
-		level = MAX_RADEON_LEVEL;
+	else if (bd->props.brightness > RADEON_MAX_BL_LEVEL)
+		level = RADEON_MAX_BL_LEVEL;
 	else
 		level = bd->props.brightness;
 
 	if (pdata->negative)
-		level = MAX_RADEON_LEVEL - level;
+		level = RADEON_MAX_BL_LEVEL - level;
 
 	return level;
 }
@@ -336,7 +329,7 @@ static int radeon_legacy_backlight_get_brightness(struct backlight_device *bd)
 	backlight_level = (RREG32(RADEON_LVDS_GEN_CNTL) >>
 			   RADEON_LVDS_BL_MOD_LEVEL_SHIFT) & 0xff;
 
-	return pdata->negative ? MAX_RADEON_LEVEL - backlight_level : backlight_level;
+	return pdata->negative ? RADEON_MAX_BL_LEVEL - backlight_level : backlight_level;
 }
 
 static const struct backlight_ops radeon_backlight_ops = {
@@ -370,7 +363,7 @@ void radeon_legacy_backlight_init(struct radeon_encoder *radeon_encoder,
 	}
 
 	memset(&props, 0, sizeof(props));
-	props.max_brightness = MAX_RADEON_LEVEL;
+	props.max_brightness = RADEON_MAX_BL_LEVEL;
 	props.type = BACKLIGHT_RAW;
 	bd = backlight_device_register("radeon_bl", &drm_connector->kdev,
 				       pdata, &radeon_backlight_ops, &props);
@@ -449,7 +442,7 @@ static void radeon_legacy_backlight_exit(struct radeon_encoder *radeon_encoder)
 	}
 
 	if (bd) {
-		struct radeon_legacy_backlight_privdata *pdata;
+		struct radeon_backlight_privdata *pdata;
 
 		pdata = bl_get_data(bd);
 		backlight_device_unregister(bd);

drivers/gpu/drm/radeon/radeon_mode.h

@@ -256,6 +256,17 @@ struct radeon_mode_info {
 	u16 firmware_flags;
 };
 
+#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
+
+#define RADEON_MAX_BL_LEVEL 0xFF
+
+struct radeon_backlight_privdata {
+	struct radeon_encoder *encoder;
+	uint8_t negative;
+};
+
+#endif
+
 #define MAX_H_CODE_TIMING_LEN 32
 #define MAX_V_CODE_TIMING_LEN 32