drm/connector: Print connector colorspace in state debugfs

v3: Fix kerneldocs (kernel test robot)

v4: Avoid returning NULL from drm_get_colorspace_name

Signed-off-by: Harry Wentland <[e-mail]>
Reviewed-by: Sebastian Wick <[e-mail]>
Reviewed-by: Joshua Ashton <[e-mail]>
Reviewed-by: Simon Ser <[e-mail]>

Cc: Pekka Paalanen <[e-mail]>
Cc: Sebastian Wick <[e-mail]>
Cc: [e-mail]
Cc: Uma Shankar <[e-mail]>
Cc: Ville Syrjälä <[e-mail]>
Cc: Joshua Ashton <[e-mail]>
Cc: Jani Nikula <[e-mail]>
Cc: Simon Ser <[e-mail]>
Cc: Melissa Wen <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/drm_atomic.c

···
 	drm_printf(p, "\tcrtc=%s\n", state->crtc ? state->crtc->name : "(null)");
 	drm_printf(p, "\tself_refresh_aware=%d\n", state->self_refresh_aware);
 	drm_printf(p, "\tmax_requested_bpc=%d\n", state->max_requested_bpc);
+	drm_printf(p, "\tcolorspace=%s\n", drm_get_colorspace_name(state->colorspace));
 
 	if (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK)
 		if (state->writeback_job && state->writeback_job->fb)

drivers/gpu/drm/drm_connector.c

···
 	[DRM_MODE_COLORIMETRY_BT601_YCC] = "BT601_YCC",
 };
 
+/**
+ * drm_get_colorspace_name - return a string for color encoding
+ * @colorspace: color space to compute name of
+ *
+ * In contrast to the other drm_get_*_name functions this one here returns a
+ * const pointer and hence is threadsafe.
+ */
+const char *drm_get_colorspace_name(enum drm_colorspace colorspace)
+{
+	if (colorspace < ARRAY_SIZE(colorspace_names) && colorspace_names[colorspace])
+		return colorspace_names[colorspace];
+	else
+		return "(null)";
+}
+
 static const u32 hdmi_colorspaces =
 	BIT(DRM_MODE_COLORIMETRY_SMPTE_170M_YCC) |
 	BIT(DRM_MODE_COLORIMETRY_BT709_YCC) |

include/drm/drm_connector.h

···
 
 bool drm_connector_has_possible_encoder(struct drm_connector *connector,
 					struct drm_encoder *encoder);
+const char *drm_get_colorspace_name(enum drm_colorspace colorspace);
 
 /**
  * drm_for_each_connector_iter - connector_list iterator macro