[PATCH 2/2] drm/sti: hda: convert to devm_drm_bridge_alloc() API

[Maxime Ripard]

Hi,

On Tue, Jul 08, 2025 at 05:24:43PM +0200, Luca Ceresoli wrote:
> 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
> 9c399719cfb9 ("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 a7748dd127ea
> ("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 at samsung.com>
> Closes: https://lore.kernel.org/all/ce9c6aa3-5372-468f-a4bf-5a261259e459@samsung.com/
> Fixes: a7748dd127ea ("drm/bridge: get/put the bridge reference in drm_bridge_add/remove()")
> Signed-off-by: Luca Ceresoli <luca.ceresoli at bootlin.com>
> ---
>  drivers/gpu/drm/sti/sti_hda.c | 27 +++++++++++++--------------
>  1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/sti/sti_hda.c b/drivers/gpu/drm/sti/sti_hda.c
> index d202b6c1eb8f6032fef547c9f00ca9cd2a914520..2c015f563de96ae58959801493ead870c49f70e5 100644
> --- a/drivers/gpu/drm/sti/sti_hda.c
> +++ b/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);

It's not entirely related, but the connector is also allocated right
before and could be moved into the structure instead of storing a
pointer.

Either way,
Reviewed-by: Maxime Ripard <mripard at kernel.org>

Maxime
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