drm/amd: Pass luminance data to amdgpu_dm_backlight_caps

The ATIF method on some systems will provide a backlight curve. Pass
this curve into amdgpu_dm add it to the structures.

Reviewed-by: Alex Hung <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mario Limonciello <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c

···
 			characteristics.max_input_signal;
 	atif->backlight_caps.ac_level = characteristics.ac_level;
 	atif->backlight_caps.dc_level = characteristics.dc_level;
+	atif->backlight_caps.data_points = characteristics.number_of_points;
+	memcpy(atif->backlight_caps.luminance_data,
+	       characteristics.data_points,
+	       sizeof(atif->backlight_caps.luminance_data));
 out:
 	kfree(info);
 	return err;

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h

···
 	bool running;
 };
 
+#define MAX_LUMINANCE_DATA_POINTS 99
+
+/**
+ * struct amdgpu_dm_luminance_data - Custom luminance data
+ * @luminance: Luminance in percent
+ * @input_signal: Input signal in range 0-255
+ */
+struct amdgpu_dm_luminance_data {
+	u8 luminance;
+	u8 input_signal;
+} __packed;
+
 /**
  * struct amdgpu_dm_backlight_caps - Information about backlight
  *
···
 	 * @dc_level: the default brightness if booted on DC
 	 */
 	u8 dc_level;
+	/**
+	 * @data_points: the number of custom luminance data points
+	 */
+	u8 data_points;
+	/**
+	 * @luminance_data: custom luminance data
+	 */
+	struct amdgpu_dm_luminance_data luminance_data[MAX_LUMINANCE_DATA_POINTS];
 };
 
 /**

drivers/gpu/drm/amd/include/amd_acpi.h

···
 
 struct atif_qbtc_data_point {
 	u8 luminance;		/* luminance in percent */
-	u8 ipnut_signal;	/* input signal in range 0-255 */
+	u8 input_signal;	/* input signal in range 0-255 */
 } __packed;
 
 struct atif_qbtc_output {
···
 	u8 number_of_points;	/* number of data points */
 	struct atif_qbtc_data_point data_points[ATIF_QBTC_MAX_DATA_POINTS];
 } __packed;
+static_assert(ATIF_QBTC_MAX_DATA_POINTS == MAX_LUMINANCE_DATA_POINTS);
+static_assert(sizeof(struct atif_qbtc_data_point) == sizeof(struct amdgpu_dm_luminance_data));
 
 #define ATIF_NOTIFY_MASK	0x3
 #define ATIF_NOTIFY_NONE	0