Re: [PATCH] drm/stm: ltdc: check number of endpoints

[Philippe CORNU <philippe.cornu@st.com>]

Dear Yannick,
Thank you for your patch,

Acked-by: Philippe Cornu <philippe.cornu@st.com>

Philippe :-)

On 1/21/20 11:14 AM, Yannick Fertre wrote:
> Number of endpoints could exceed the fix value MAX_ENDPOINTS(2).
> Instead of increase simply this value, the number of endpoint
> could be read from device tree. Load sequence has been a little
> rework to take care of several panel or bridge which can be
> connected/disconnected or enable/disable.
> 
> Signed-off-by: Yannick Fertré <yannick.fertre@st.com>
> ---
>   drivers/gpu/drm/stm/ltdc.c | 104 ++++++++++++++++++++++-----------------------
>   1 file changed, 52 insertions(+), 52 deletions(-)
> 
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index c2815e8..dba8e7f 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -42,8 +42,6 @@
>   
>   #define MAX_IRQ 4
>   
> -#define MAX_ENDPOINTS 2
> -
>   #define HWVER_10200 0x010200
>   #define HWVER_10300 0x010300
>   #define HWVER_20101 0x020101
> @@ -1190,36 +1188,20 @@ int ltdc_load(struct drm_device *ddev)
>   	struct ltdc_device *ldev = ddev->dev_private;
>   	struct device *dev = ddev->dev;
>   	struct device_node *np = dev->of_node;
> -	struct drm_bridge *bridge[MAX_ENDPOINTS] = {NULL};
> -	struct drm_panel *panel[MAX_ENDPOINTS] = {NULL};
> +	struct drm_bridge *bridge;
> +	struct drm_panel *panel;
>   	struct drm_crtc *crtc;
>   	struct reset_control *rstc;
>   	struct resource *res;
> -	int irq, ret, i, endpoint_not_ready = -ENODEV;
> +	int irq, i, nb_endpoints;
> +	int ret = -ENODEV;
>   
>   	DRM_DEBUG_DRIVER("\n");
>   
> -	/* Get endpoints if any */
> -	for (i = 0; i < MAX_ENDPOINTS; i++) {
> -		ret = drm_of_find_panel_or_bridge(np, 0, i, &panel[i],
> -						  &bridge[i]);
> -
> -		/*
> -		 * If at least one endpoint is -EPROBE_DEFER, defer probing,
> -		 * else if at least one endpoint is ready, continue probing.
> -		 */
> -		if (ret == -EPROBE_DEFER)
> -			return ret;
> -		else if (!ret)
> -			endpoint_not_ready = 0;
> -	}
> -
> -	if (endpoint_not_ready)
> -		return endpoint_not_ready;
> -
> -	rstc = devm_reset_control_get_exclusive(dev, NULL);
> -
> -	mutex_init(&ldev->err_lock);
> +	/* Get number of endpoints */
> +	nb_endpoints = of_graph_get_endpoint_count(np);
> +	if (!nb_endpoints)
> +		return -ENODEV;
>   
>   	ldev->pixel_clk = devm_clk_get(dev, "lcd");
>   	if (IS_ERR(ldev->pixel_clk)) {
> @@ -1233,6 +1215,43 @@ int ltdc_load(struct drm_device *ddev)
>   		return -ENODEV;
>   	}
>   
> +	/* Get endpoints if any */
> +	for (i = 0; i < nb_endpoints; i++) {
> +		ret = drm_of_find_panel_or_bridge(np, 0, i, &panel, &bridge);
> +
> +		/*
> +		 * If at least one endpoint is -ENODEV, continue probing,
> +		 * else if at least one endpoint returned an error
> +		 * (ie -EPROBE_DEFER) then stop probing.
> +		 */
> +		if (ret == -ENODEV)
> +			continue;
> +		else if (ret)
> +			goto err;
> +
> +		if (panel) {
> +			bridge = drm_panel_bridge_add_typed(panel,
> +							    DRM_MODE_CONNECTOR_DPI);
> +			if (IS_ERR(bridge)) {
> +				DRM_ERROR("panel-bridge endpoint %d\n", i);
> +				ret = PTR_ERR(bridge);
> +				goto err;
> +			}
> +		}
> +
> +		if (bridge) {
> +			ret = ltdc_encoder_init(ddev, bridge);
> +			if (ret) {
> +				DRM_ERROR("init encoder endpoint %d\n", i);
> +				goto err;
> +			}
> +		}
> +	}
> +
> +	rstc = devm_reset_control_get_exclusive(dev, NULL);
> +
> +	mutex_init(&ldev->err_lock);
> +
>   	if (!IS_ERR(rstc)) {
>   		reset_control_assert(rstc);
>   		usleep_range(10, 20);
> @@ -1268,7 +1287,6 @@ int ltdc_load(struct drm_device *ddev)
>   		}
>   	}
>   
> -
>   	ret = ltdc_get_caps(ddev);
>   	if (ret) {
>   		DRM_ERROR("hardware identifier (0x%08x) not supported!\n",
> @@ -1278,27 +1296,6 @@ int ltdc_load(struct drm_device *ddev)
>   
>   	DRM_DEBUG_DRIVER("ltdc hw version 0x%08x\n", ldev->caps.hw_version);
>   
> -	/* Add endpoints panels or bridges if any */
> -	for (i = 0; i < MAX_ENDPOINTS; i++) {
> -		if (panel[i]) {
> -			bridge[i] = drm_panel_bridge_add_typed(panel[i],
> -							       DRM_MODE_CONNECTOR_DPI);
> -			if (IS_ERR(bridge[i])) {
> -				DRM_ERROR("panel-bridge endpoint %d\n", i);
> -				ret = PTR_ERR(bridge[i]);
> -				goto err;
> -			}
> -		}
> -
> -		if (bridge[i]) {
> -			ret = ltdc_encoder_init(ddev, bridge[i]);
> -			if (ret) {
> -				DRM_ERROR("init encoder endpoint %d\n", i);
> -				goto err;
> -			}
> -		}
> -	}
> -
>   	crtc = devm_kzalloc(dev, sizeof(*crtc), GFP_KERNEL);
>   	if (!crtc) {
>   		DRM_ERROR("Failed to allocate crtc\n");
> @@ -1331,8 +1328,8 @@ int ltdc_load(struct drm_device *ddev)
>   
>   	return 0;
>   err:
> -	for (i = 0; i < MAX_ENDPOINTS; i++)
> -		drm_panel_bridge_remove(bridge[i]);
> +	for (i = 0; i < nb_endpoints; i++)
> +		drm_of_panel_bridge_remove(ddev->dev->of_node, 0, i);
>   
>   	clk_disable_unprepare(ldev->pixel_clk);
>   
> @@ -1341,11 +1338,14 @@ int ltdc_load(struct drm_device *ddev)
>   
>   void ltdc_unload(struct drm_device *ddev)
>   {
> -	int i;
> +	struct device *dev = ddev->dev;
> +	int nb_endpoints, i;
>   
>   	DRM_DEBUG_DRIVER("\n");
>   
> -	for (i = 0; i < MAX_ENDPOINTS; i++)
> +	nb_endpoints = of_graph_get_endpoint_count(dev->of_node);
> +
> +	for (i = 0; i < nb_endpoints; i++)
>   		drm_of_panel_bridge_remove(ddev->dev->of_node, 0, i);
>   
>   	pm_runtime_disable(ddev->dev);
>