[PATCH] drm/simple_kms_helper: add drmm_simple_encoder_init()

[Philipp Zabel]

Add a drm_simple_encoder_init() variant that registers
drm_encoder_cleanup() with drmm_add_action().

Now drivers can store encoders in memory allocated with drmm_kmalloc()
after the call to drmm_mode_config_init(), without having to manually
make sure that drm_encoder_cleanup() is called before the memory is
freed.

Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
---
 drivers/gpu/drm/drm_simple_kms_helper.c | 42 +++++++++++++++++++++++++
 include/drm/drm_simple_kms_helper.h     |  4 +++
 2 files changed, 46 insertions(+)

diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c
index 74946690aba4..a243f00cf63d 100644
--- a/drivers/gpu/drm/drm_simple_kms_helper.c
+++ b/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>
@@ -71,6 +72,47 @@ int drm_simple_encoder_init(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_simple_encoder_init);
 
+static void drmm_encoder_cleanup(struct drm_device *dev, void *ptr)
+{
+	struct drm_encoder *encoder = ptr;
+
+	drm_encoder_cleanup(encoder);
+}
+
+/**
+ * drmm_simple_encoder_init - Initialize a preallocated encoder with
+ *                            basic functionality.
+ * @dev: drm device
+ * @encoder: the encoder to initialize
+ * @encoder_type: user visible type of the encoder
+ *
+ * Initialises a preallocated 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().
+ *
+ * The caller of drmm_simple_encoder_init() is responsible for allocating
+ * the encoder's memory with drmm_kzalloc() to ensure it is automatically
+ * freed after the encoder has been cleaned up.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drmm_simple_encoder_init(struct drm_device *dev,
+			     struct drm_encoder *encoder,
+			     int encoder_type)
+{
+	int ret;
+
+	ret = drm_encoder_init(dev, encoder, &drm_simple_encoder_funcs_cleanup,
+			       encoder_type, NULL);
+	if (ret)
+		return ret;
+
+	return drmm_add_action_or_reset(dev, drmm_encoder_cleanup, encoder);
+}
+EXPORT_SYMBOL(drmm_simple_encoder_init);
+
 static enum drm_mode_status
 drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
 			       const struct drm_display_mode *mode)
diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
index a026375464ff..27f0915599c8 100644
--- a/include/drm/drm_simple_kms_helper.h
+++ b/include/drm/drm_simple_kms_helper.h
@@ -185,4 +185,8 @@ int drm_simple_encoder_init(struct drm_device *dev,
 			    struct drm_encoder *encoder,
 			    int encoder_type);
 
+int drmm_simple_encoder_init(struct drm_device *dev,
+			     struct drm_encoder *encoder,
+			     int encoder_type);
+
 #endif /* __LINUX_DRM_SIMPLE_KMS_HELPER_H */
-- 
2.20.1