drm/sti: hdmi: convert to devm_drm_bridge_alloc() API

devm_drm_bridge_alloc() is the new API to be used for allocating (and
partially initializing) a private driver struct embedding a struct
drm_bridge.

This driver was missed during the automated conversion in commit
9c39971 ("drm: convert many bridge drivers from devm_kzalloc() to
devm_drm_bridge_alloc() API") and following commits.

The lack of conversion for this driver is a bug since commit a7748dd
("drm/bridge: get/put the bridge reference in drm_bridge_add/remove()")
which is the first commmit having added a drm_bridge_get/put() pair and
thus exposing the incorrect initial refcount issue.

Fix this by switching the driver to the new API.

Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/all/ce9c6aa3-5372-468f-a4bf-5a261259e459@samsung.com/
Fixes: a7748dd ("drm/bridge: get/put the bridge reference in drm_bridge_add/remove()")
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250708-drm-bridge-convert-to-alloc-api-leftovers-v1-1-6285de8c3759@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Author: lucaceresoli

drivers/gpu/drm/sti/sti_hdmi.c

@@ -168,6 +168,11 @@ struct sti_hdmi_connector {
 #define to_sti_hdmi_connector(x) \
 	container_of(x, struct sti_hdmi_connector, drm_connector)
 
+static struct sti_hdmi *drm_bridge_to_sti_hdmi(struct drm_bridge *bridge)
+{
+	return container_of(bridge, struct sti_hdmi, bridge);
+}
+
 static const struct drm_prop_enum_list colorspace_mode_names[] = {
 	{ HDMI_COLORSPACE_RGB, "rgb" },
 	{ HDMI_COLORSPACE_YUV422, "yuv422" },
@@ -749,7 +754,7 @@ static void hdmi_debugfs_init(struct sti_hdmi *hdmi, struct drm_minor *minor)
 
 static void sti_hdmi_disable(struct drm_bridge *bridge)
 {
-	struct sti_hdmi *hdmi = bridge->driver_private;
+	struct sti_hdmi *hdmi = drm_bridge_to_sti_hdmi(bridge);
 
 	u32 val = hdmi_read(hdmi, HDMI_CFG);
 
@@ -881,7 +886,7 @@ static int hdmi_audio_configure(struct sti_hdmi *hdmi)
 
 static void sti_hdmi_pre_enable(struct drm_bridge *bridge)
 {
-	struct sti_hdmi *hdmi = bridge->driver_private;
+	struct sti_hdmi *hdmi = drm_bridge_to_sti_hdmi(bridge);
 
 	DRM_DEBUG_DRIVER("\n");
 
@@ -936,7 +941,7 @@ static void sti_hdmi_set_mode(struct drm_bridge *bridge,
 			      const struct drm_display_mode *mode,
 			      const struct drm_display_mode *adjusted_mode)
 {
-	struct sti_hdmi *hdmi = bridge->driver_private;
+	struct sti_hdmi *hdmi = drm_bridge_to_sti_hdmi(bridge);
 	int ret;
 
 	DRM_DEBUG_DRIVER("\n");
@@ -1273,7 +1278,6 @@ static int sti_hdmi_bind(struct device *dev, struct device *master, void *data)
 	struct sti_hdmi_connector *connector;
 	struct cec_connector_info conn_info;
 	struct drm_connector *drm_connector;
-	struct drm_bridge *bridge;
 	int err;
 
 	/* Set the drm device handle */
@@ -1289,13 +1293,7 @@ static int sti_hdmi_bind(struct device *dev, struct device *master, void *data)
 
 	connector->hdmi = hdmi;
 
-	bridge = devm_kzalloc(dev, sizeof(*bridge), GFP_KERNEL);
-	if (!bridge)
-		return -EINVAL;
-
-	bridge->driver_private = hdmi;
-	bridge->funcs = &sti_hdmi_bridge_funcs;
-	drm_bridge_attach(encoder, bridge, NULL, 0);
+	drm_bridge_attach(encoder, &hdmi->bridge, NULL, 0);
 
 	connector->encoder = encoder;
 
@@ -1385,9 +1383,9 @@ static int sti_hdmi_probe(struct platform_device *pdev)
 
 	DRM_INFO("%s\n", __func__);
 
-	hdmi = devm_kzalloc(dev, sizeof(*hdmi), GFP_KERNEL);
-	if (!hdmi)
-		return -ENOMEM;
+	hdmi = devm_drm_bridge_alloc(dev, struct sti_hdmi, bridge, &sti_hdmi_bridge_funcs);
+	if (IS_ERR(hdmi))
+		return PTR_ERR(hdmi);
 
 	ddc = of_parse_phandle(pdev->dev.of_node, "ddc", 0);
 	if (ddc) {

drivers/gpu/drm/sti/sti_hdmi.h

@@ -12,6 +12,7 @@
 
 #include <media/cec-notifier.h>
 
+#include <drm/drm_bridge.h>
 #include <drm/drm_modes.h>
 #include <drm/drm_property.h>
 
@@ -86,6 +87,7 @@ struct sti_hdmi {
 	struct hdmi_audio_params audio;
 	struct drm_connector *drm_connector;
 	struct cec_notifier *notifier;
+	struct drm_bridge bridge;
 };
 
 u32 hdmi_read(struct sti_hdmi *hdmi, int offset);