drm/sti: hda: 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 <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Fixes: a7748dd ("drm/bridge: get/put the bridge reference in drm_bridge_add/remove()")
Reviewed-by: Maxime Ripard <[email protected]>
Link: https://lore.kernel.org/r/20250708-drm-bridge-convert-to-alloc-api-leftovers-v1-2-6285de8c3759@bootlin.com
Signed-off-by: Luca Ceresoli <[email protected]>

Author: lucaceresoli

drivers/gpu/drm/sti/sti_hda.c

@@ -246,6 +246,7 @@ struct sti_hda {
 	struct device dev;
 	struct drm_device *drm_dev;
 	struct drm_display_mode mode;
+	struct drm_bridge bridge;
 	void __iomem *regs;
 	void __iomem *video_dacs_ctrl;
 	struct clk *clk_pix;
@@ -262,6 +263,11 @@ struct sti_hda_connector {
 #define to_sti_hda_connector(x) \
 	container_of(x, struct sti_hda_connector, drm_connector)
 
+static struct sti_hda *drm_bridge_to_sti_hda(struct drm_bridge *bridge)
+{
+	return container_of(bridge, struct sti_hda, bridge);
+}
+
 static u32 hda_read(struct sti_hda *hda, int offset)
 {
 	return readl(hda->regs + offset);
@@ -401,7 +407,7 @@ static void sti_hda_configure_awg(struct sti_hda *hda, u32 *awg_instr, int nb)
 
 static void sti_hda_disable(struct drm_bridge *bridge)
 {
-	struct sti_hda *hda = bridge->driver_private;
+	struct sti_hda *hda = drm_bridge_to_sti_hda(bridge);
 	u32 val;
 
 	if (!hda->enabled)
@@ -426,7 +432,7 @@ static void sti_hda_disable(struct drm_bridge *bridge)
 
 static void sti_hda_pre_enable(struct drm_bridge *bridge)
 {
-	struct sti_hda *hda = bridge->driver_private;
+	struct sti_hda *hda = drm_bridge_to_sti_hda(bridge);
 	u32 val, i, mode_idx;
 	u32 src_filter_y, src_filter_c;
 	u32 *coef_y, *coef_c;
@@ -517,7 +523,7 @@ static void sti_hda_set_mode(struct drm_bridge *bridge,
 			     const struct drm_display_mode *mode,
 			     const struct drm_display_mode *adjusted_mode)
 {
-	struct sti_hda *hda = bridge->driver_private;
+	struct sti_hda *hda = drm_bridge_to_sti_hda(bridge);
 	u32 mode_idx;
 	int hddac_rate;
 	int ret;
@@ -677,7 +683,6 @@ static int sti_hda_bind(struct device *dev, struct device *master, void *data)
 	struct drm_encoder *encoder;
 	struct sti_hda_connector *connector;
 	struct drm_connector *drm_connector;
-	struct drm_bridge *bridge;
 	int err;
 
 	/* Set the drm device handle */
@@ -693,13 +698,7 @@ static int sti_hda_bind(struct device *dev, struct device *master, void *data)
 
 	connector->hda = hda;
 
-	bridge = devm_kzalloc(dev, sizeof(*bridge), GFP_KERNEL);
-	if (!bridge)
-		return -ENOMEM;
-
-	bridge->driver_private = hda;
-	bridge->funcs = &sti_hda_bridge_funcs;
-	drm_bridge_attach(encoder, bridge, NULL, 0);
+	drm_bridge_attach(encoder, &hda->bridge, NULL, 0);
 
 	connector->encoder = encoder;
 
@@ -745,9 +744,9 @@ static int sti_hda_probe(struct platform_device *pdev)
 
 	DRM_INFO("%s\n", __func__);
 
-	hda = devm_kzalloc(dev, sizeof(*hda), GFP_KERNEL);
-	if (!hda)
-		return -ENOMEM;
+	hda = devm_drm_bridge_alloc(dev, struct sti_hda, bridge, &sti_hda_bridge_funcs);
+	if (IS_ERR(hda))
+		return PTR_ERR(hda);
 
 	hda->dev = pdev->dev;
 	hda->regs = devm_platform_ioremap_resource_byname(pdev, "hda-reg");