drm/simple_kms_helper: add drmm_simple_encoder_alloc()

Add an alternative to drm_simple_encoder_init() that allocates and
initializes a simple encoder and registers drm_encoder_cleanup() with
drmm_add_action_or_reset().
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_simple_kms_helper.c

@@ -9,6 +9,7 @@
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
+#include <drm/drm_managed.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_simple_kms_helper.h>
@@ -55,8 +56,9 @@ static const struct drm_encoder_funcs drm_simple_encoder_funcs_cleanup = {
  * stored in the device structure. Free the encoder's memory as part of
  * the device release function.
  *
- * FIXME: Later improvements to DRM's resource management may allow for
- *        an automated kfree() of the encoder's memory.
+ * Note: consider using drmm_simple_encoder_alloc() instead of
+ * drm_simple_encoder_init() to let the DRM managed resource infrastructure
+ * take care of cleanup and deallocation.
  *
  * Returns:
  * Zero on success, error code on failure.
@@ -71,6 +73,14 @@ int drm_simple_encoder_init(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_simple_encoder_init);
 
+void *__drmm_simple_encoder_alloc(struct drm_device *dev, size_t size,
+				  size_t offset, int encoder_type)
+{
+	return __drmm_encoder_alloc(dev, size, offset, NULL, encoder_type,
+				    NULL);
+}
+EXPORT_SYMBOL(__drmm_simple_encoder_alloc);
+
 static enum drm_mode_status
 drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
 			       const struct drm_display_mode *mode)

include/drm/drm_simple_kms_helper.h

@@ -185,4 +185,28 @@ int drm_simple_encoder_init(struct drm_device *dev,
 			    struct drm_encoder *encoder,
 			    int encoder_type);
 
+void *__drmm_simple_encoder_alloc(struct drm_device *dev, size_t size,
+				  size_t offset, int encoder_type);
+
+/**
+ * drmm_simple_encoder_alloc - Allocate and initialize an encoder with basic
+ *                             functionality.
+ * @dev: drm device
+ * @type: the type of the struct which contains struct &drm_encoder
+ * @member: the name of the &drm_encoder within @type.
+ * @encoder_type: user visible type of the encoder
+ *
+ * Allocates and initializes an encoder that has no further functionality.
+ * Settings for possible CRTC and clones are left to their initial values.
+ * Cleanup is automatically handled through registering drm_encoder_cleanup()
+ * with drmm_add_action().
+ *
+ * Returns:
+ * Pointer to new encoder, or ERR_PTR on failure.
+ */
+#define drmm_simple_encoder_alloc(dev, type, member, encoder_type) \
+	((type *)__drmm_simple_encoder_alloc(dev, sizeof(type), \
+					     offsetof(type, member), \
+					     encoder_type))
+
 #endif /* __LINUX_DRM_SIMPLE_KMS_HELPER_H */