drm/amd/display: Add debugfs for testing output colorspace

In order to IGT test colorspace we'll want to print
the currently enabled colorspace on a stream. We add
a new debugfs to do so, using the same scheme as
current bpc reporting.

This might also come in handy when debugging display
issues.

v4:
- Fix function doc comment
- Fix sRGB debug print

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Joshua Ashton <joshua@froggi.es>

Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Sebastian Wick <sebastian.wick@redhat.com>
Cc: Vitaly.Prosyak@amd.com
Cc: Joshua Ashton <joshua@froggi.es>
Cc: Simon Ser <contact@emersion.fr>
Cc: Melissa Wen <mwen@igalia.com>
Cc: dri-devel@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Harry Wentland

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c

@@ -906,6 +906,61 @@ static int amdgpu_current_bpc_show(struct seq_file *m, void *data)
 }
 DEFINE_SHOW_ATTRIBUTE(amdgpu_current_bpc);
 
+/*
+ * Returns the current colorspace for the crtc.
+ * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/amdgpu_current_colorspace
+ */
+static int amdgpu_current_colorspace_show(struct seq_file *m, void *data)
+{
+	struct drm_crtc *crtc = m->private;
+	struct drm_device *dev = crtc->dev;
+	struct dm_crtc_state *dm_crtc_state = NULL;
+	int res = -ENODEV;
+
+	mutex_lock(&dev->mode_config.mutex);
+	drm_modeset_lock(&crtc->mutex, NULL);
+	if (crtc->state == NULL)
+		goto unlock;
+
+	dm_crtc_state = to_dm_crtc_state(crtc->state);
+	if (dm_crtc_state->stream == NULL)
+		goto unlock;
+
+	switch (dm_crtc_state->stream->output_color_space) {
+	case COLOR_SPACE_SRGB:
+		seq_printf(m, "sRGB");
+		break;
+	case COLOR_SPACE_YCBCR601:
+	case COLOR_SPACE_YCBCR601_LIMITED:
+		seq_printf(m, "BT601_YCC");
+		break;
+	case COLOR_SPACE_YCBCR709:
+	case COLOR_SPACE_YCBCR709_LIMITED:
+		seq_printf(m, "BT709_YCC");
+		break;
+	case COLOR_SPACE_ADOBERGB:
+		seq_printf(m, "opRGB");
+		break;
+	case COLOR_SPACE_2020_RGB_FULLRANGE:
+		seq_printf(m, "BT2020_RGB");
+		break;
+	case COLOR_SPACE_2020_YCBCR:
+		seq_printf(m, "BT2020_YCC");
+		break;
+	default:
+		goto unlock;
+	}
+	res = 0;
+
+unlock:
+	drm_modeset_unlock(&crtc->mutex);
+	mutex_unlock(&dev->mode_config.mutex);
+
+	return res;
+}
+DEFINE_SHOW_ATTRIBUTE(amdgpu_current_colorspace);
+
+
 /*
  * Example usage:
  * Disable dsc passthrough, i.e.,: have dsc decoding at converver, not external RX
@@ -3139,6 +3194,8 @@ void crtc_debugfs_init(struct drm_crtc *crtc)
 #endif
 	debugfs_create_file("amdgpu_current_bpc", 0644, crtc->debugfs_entry,
 			    crtc, &amdgpu_current_bpc_fops);
+	debugfs_create_file("amdgpu_current_colorspace", 0644, crtc->debugfs_entry,
+			    crtc, &amdgpu_current_colorspace_fops);
 }
 
 /*