[PATCH v5 2/4] drm: introduce drm_writeback_connector_init_with_encoder() API

[Abhinav Kumar]

For vendors drivers which pass an already allocated and
initialized encoder especially for cases where the encoder
hardware is shared OR the writeback encoder shares the resources
with the rest of the display pipeline introduce a new API,
drm_writeback_connector_init_with_encoder() which expects
an initialized encoder as a parameter and only sets up the
writeback connector.

changes in v5:
	- reorder this change to come before in the series
	  to avoid incorrect functionality in subsequent changes
	- continue using struct drm_encoder instead of
	  struct drm_encoder * and switch it in next change

Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
---
 drivers/gpu/drm/drm_writeback.c | 143 ++++++++++++++++++++++++++++------------
 include/drm/drm_writeback.h     |   5 ++
 2 files changed, 106 insertions(+), 42 deletions(-)

diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
index dc2ef12..abe78b9 100644
--- a/drivers/gpu/drm/drm_writeback.c
+++ b/drivers/gpu/drm/drm_writeback.c
@@ -149,37 +149,15 @@ static const struct drm_encoder_funcs drm_writeback_encoder_funcs = {
 	.destroy = drm_encoder_cleanup,
 };
 
-/**
- * drm_writeback_connector_init - Initialize a writeback connector and its properties
- * @dev: DRM device
- * @wb_connector: Writeback connector to initialize
- * @con_funcs: Connector funcs vtable
- * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder
- * @formats: Array of supported pixel formats for the writeback engine
- * @n_formats: Length of the formats array
- * @possible_crtcs: possible crtcs for the internal writeback encoder
- *
- * This function creates the writeback-connector-specific properties if they
- * have not been already created, initializes the connector as
- * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property
- * values. It will also create an internal encoder associated with the
- * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for
- * the encoder helper.
- *
- * Drivers should always use this function instead of drm_connector_init() to
- * set up writeback connectors.
- *
- * Returns: 0 on success, or a negative error code
- */
-int drm_writeback_connector_init(struct drm_device *dev,
-				 struct drm_writeback_connector *wb_connector,
-				 const struct drm_connector_funcs *con_funcs,
-				 const struct drm_encoder_helper_funcs *enc_helper_funcs,
-				 const u32 *formats, int n_formats, uint32_t possible_crtcs)
+static int drm_writeback_connector_setup(struct drm_device *dev,
+		struct drm_writeback_connector *wb_connector,
+		const struct drm_connector_funcs *con_funcs, const u32 *formats,
+		int n_formats)
 {
 	struct drm_property_blob *blob;
-	struct drm_connector *connector = &wb_connector->base;
 	struct drm_mode_config *config = &dev->mode_config;
+	struct drm_connector *connector = &wb_connector->base;
+
 	int ret = create_writeback_properties(dev);
 
 	if (ret != 0)
@@ -187,18 +165,10 @@ int drm_writeback_connector_init(struct drm_device *dev,
 
 	blob = drm_property_create_blob(dev, n_formats * sizeof(*formats),
 					formats);
-	if (IS_ERR(blob))
-		return PTR_ERR(blob);
-
-	drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs);
-
-	wb_connector->encoder.possible_crtcs = possible_crtcs;
-
-	ret = drm_encoder_init(dev, &wb_connector->encoder,
-			       &drm_writeback_encoder_funcs,
-			       DRM_MODE_ENCODER_VIRTUAL, NULL);
-	if (ret)
-		goto fail;
+	if (IS_ERR(blob)) {
+		ret = PTR_ERR(blob);
+		return ret;
+	}
 
 	connector->interlace_allowed = 0;
 
@@ -237,13 +207,102 @@ int drm_writeback_connector_init(struct drm_device *dev,
 attach_fail:
 	drm_connector_cleanup(connector);
 connector_fail:
-	drm_encoder_cleanup(&wb_connector->encoder);
-fail:
 	drm_property_blob_put(blob);
 	return ret;
 }
+
+/**
+ * drm_writeback_connector_init - Initialize a writeback connector and its properties
+ * @dev: DRM device
+ * @wb_connector: Writeback connector to initialize
+ * @con_funcs: Connector funcs vtable
+ * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder
+ * @formats: Array of supported pixel formats for the writeback engine
+ * @n_formats: Length of the formats array
+ * @possible_crtcs: possible crtcs for the internal writeback encoder
+ *
+ * This function creates the writeback-connector-specific properties if they
+ * have not been already created, initializes the connector as
+ * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property
+ * values. It will also create an internal encoder associated with the
+ * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for
+ * the encoder helper.
+ *
+ * Drivers should always use this function instead of drm_connector_init() to
+ * set up writeback connectors.
+ *
+ * Returns: 0 on success, or a negative error code
+ */
+int drm_writeback_connector_init(struct drm_device *dev,
+		struct drm_writeback_connector *wb_connector,
+		const struct drm_connector_funcs *con_funcs,
+		const struct drm_encoder_helper_funcs *enc_helper_funcs,
+		const u32 *formats, int n_formats, uint32_t possible_crtcs)
+{
+	int ret = 0;
+
+	drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs);
+
+	wb_connector->encoder.possible_crtcs = possible_crtcs;
+
+	ret = drm_encoder_init(dev, &wb_connector->encoder,
+			       &drm_writeback_encoder_funcs,
+			       DRM_MODE_ENCODER_VIRTUAL, NULL);
+	if (ret)
+		return ret;
+
+	ret = drm_writeback_connector_setup(dev, wb_connector, con_funcs, formats,
+			n_formats);
+
+	if (ret)
+		drm_encoder_cleanup(&wb_connector->encoder);
+
+	return ret;
+}
 EXPORT_SYMBOL(drm_writeback_connector_init);
 
+/**
+ * drm_writeback_connector_init_with_encoder - Initialize a writeback connector and its properties
+ * using the encoder which already assigned and initialized
+ *
+ * @dev: DRM device
+ * @wb_connector: Writeback connector to initialize
+ * @con_funcs: Connector funcs vtable
+ * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder
+ * @formats: Array of supported pixel formats for the writeback engine
+ * @n_formats: Length of the formats array
+ *
+ * This function creates the writeback-connector-specific properties if they
+ * have not been already created, initializes the connector as
+ * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property
+ * values.
+ *
+ * This function assumes that the drm_writebac_connector's encoder has already been
+ * created and initialized before invoking this function.
+ *
+ * In addition, this function also assumes that callers of this API will manage
+ * assigning the encoder helper functions, possible_crtcs and any other encoder
+ * specific operation which is otherwise handled by drm_writeback_connector_init().
+ *
+ * Drivers should always use this function instead of drm_connector_init() to
+ * set up writeback connectors.
+ *
+ * Returns: 0 on success, or a negative error code
+ */
+int drm_writeback_connector_init_with_encoder(struct drm_device *dev,
+		struct drm_writeback_connector *wb_connector,
+		const struct drm_connector_funcs *con_funcs, const u32 *formats,
+		int n_formats)
+{
+	int ret = 0;
+
+	ret = drm_writeback_connector_setup(dev, wb_connector, con_funcs, formats,
+			n_formats);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_writeback_connector_init_with_encoder);
+
 int drm_writeback_set_fb(struct drm_connector_state *conn_state,
 			 struct drm_framebuffer *fb)
 {
diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
index db6214f..0093bab 100644
--- a/include/drm/drm_writeback.h
+++ b/include/drm/drm_writeback.h
@@ -152,6 +152,11 @@ int drm_writeback_connector_init(struct drm_device *dev,
 				 const struct drm_encoder_helper_funcs *enc_helper_funcs,
 				 const u32 *formats, int n_formats, uint32_t possible_crtcs);
 
+int drm_writeback_connector_init_with_encoder(struct drm_device *dev,
+				struct drm_writeback_connector *wb_connector,
+				const struct drm_connector_funcs *con_funcs, const u32 *formats,
+				int n_formats);
+
 int drm_writeback_set_fb(struct drm_connector_state *conn_state,
 			 struct drm_framebuffer *fb);
 
-- 
2.7.4