drm: expose subpixel order name routine v3

Just like we have for connector type etc.

v2: drop static array (Chris)
v3: add kdoc (Daniel)

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_crtc.c

@@ -215,6 +215,16 @@ static const struct drm_prop_enum_list drm_encoder_enum_list[] =
 	{ DRM_MODE_ENCODER_DSI, "DSI" },
 };
 
+static const struct drm_prop_enum_list drm_subpixel_enum_list[] =
+{
+	{ SubPixelUnknown, "Unknown" },
+	{ SubPixelHorizontalRGB, "Horizontal RGB" },
+	{ SubPixelHorizontalBGR, "Horizontal BGR" },
+	{ SubPixelVerticalRGB, "Vertical RGB" },
+	{ SubPixelVerticalBGR, "Vertical BGR" },
+	{ SubPixelNone, "None" },
+};
+
 void drm_connector_ida_init(void)
 {
 	int i;
@@ -264,6 +274,19 @@ const char *drm_get_connector_status_name(enum drm_connector_status status)
 }
 EXPORT_SYMBOL(drm_get_connector_status_name);
 
+/**
+ * drm_get_subpixel_order_name - return a string for a given subpixel enum
+ * @order: enum of subpixel_order
+ *
+ * Note you could abuse this and return something out of bounds, but that
+ * would be a caller error.  No unscrubbed user data should make it here.
+ */
+const char *drm_get_subpixel_order_name(enum subpixel_order order)
+{
+	return drm_subpixel_enum_list[order].name;
+}
+EXPORT_SYMBOL(drm_get_subpixel_order_name);
+
 static char printable_char(int c)
 {
 	return isascii(c) && isprint(c) ? c : '?';

include/drm/drm_crtc.h

@@ -991,6 +991,7 @@ extern void drm_encoder_cleanup(struct drm_encoder *encoder);
 
 extern const char *drm_get_connector_name(const struct drm_connector *connector);
 extern const char *drm_get_connector_status_name(enum drm_connector_status status);
+extern const char *drm_get_subpixel_order_name(enum subpixel_order order);
 extern const char *drm_get_dpms_name(int val);
 extern const char *drm_get_dvi_i_subconnector_name(int val);
 extern const char *drm_get_dvi_i_select_name(int val);