[PATCH 1/3] drm: add crtc helper drm_crtc_from_index()

[Shawn Guo]

From: Shawn Guo <shawn.guo at linaro.org>

It adds a crtc helper drm_crtc_from_index() to find the registered CRTC
with a given index, just like drm_plane_from_index().

Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
---
 drivers/gpu/drm/drm_crtc.c | 20 ++++++++++++++++++++
 include/drm/drm_crtc.h     |  1 +
 2 files changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index e75f62cd8a65..5c1bb1f34697 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -47,6 +47,26 @@
 #include "drm_internal.h"
 
 /**
+ * drm_crtc_from_index - find the registered CRTC at an index
+ * @dev: DRM device
+ * @idx: index of registered CRTC to find for
+ *
+ * Given a CRTC index, return the registered CRTC from DRM device's
+ * list of CRTCs with matching index.
+ */
+struct drm_crtc *drm_crtc_from_index(struct drm_device *dev, int idx)
+{
+	struct drm_crtc *crtc;
+
+	drm_for_each_crtc(crtc, dev)
+		if (idx == crtc->index)
+			return crtc;
+
+	return NULL;
+}
+EXPORT_SYMBOL(drm_crtc_from_index);
+
+/**
  * drm_crtc_force_disable - Forcibly turn off a CRTC
  * @crtc: CRTC to turn off
  *
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 946672f97e1e..a5627eb8621f 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -830,6 +830,7 @@ void drm_crtc_get_hv_timing(const struct drm_display_mode *mode,
 int drm_crtc_force_disable_all(struct drm_device *dev);
 
 int drm_mode_set_config_internal(struct drm_mode_set *set);
+struct drm_crtc *drm_crtc_from_index(struct drm_device *dev, int idx);
 
 /* Helpers */
 static inline struct drm_crtc *drm_crtc_find(struct drm_device *dev,
-- 
1.9.1