Re: [PATCH v5 7/7] drm/msm/dp: move of_dp_aux_populate_bus() to eDP probe()

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On 04/10/2023 19:27, Kuogee Hsieh wrote:
> Currently eDP population is done at msm_dp_modeset_init() which happen
> at binding time. Move eDP population to be done at display probe time
> so that probe deferral cases can be handled effectively.
> wait_for_hpd_asserted callback is added during drm_dp_aux_init()
> to ensure eDP's HPD is up before proceeding eDP population.
> 
> Changes in v5:
> -- inline dp_display_auxbus_population() and delete it
> 
> Changes in v4:
> -- delete duplicate initialize code to dp_aux before drm_dp_aux_register()
> -- delete of_get_child_by_name(dev->of_node, "aux-bus") and inline the function
> -- not initialize rc = 0
> 
> Changes in v3:
> -- add done_probing callback into devm_of_dp_aux_populate_bus()
> 
> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
> ---
>   drivers/gpu/drm/msm/dp/dp_aux.c     | 34 ++++++++++++++++-----
>   drivers/gpu/drm/msm/dp/dp_display.c | 59 +++++++++++++++----------------------
>   2 files changed, 51 insertions(+), 42 deletions(-)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
> index 10b6eeb..03f4951 100644
> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
> @@ -479,7 +479,6 @@ void dp_aux_deinit(struct drm_dp_aux *dp_aux)
>   
>   int dp_aux_register(struct drm_dp_aux *dp_aux)
>   {
> -	struct dp_aux_private *aux;
>   	int ret;
>   
>   	if (!dp_aux) {
> @@ -487,12 +486,7 @@ int dp_aux_register(struct drm_dp_aux *dp_aux)
>   		return -EINVAL;
>   	}
>   
> -	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
> -
> -	aux->dp_aux.name = "dpu_dp_aux";
> -	aux->dp_aux.dev = aux->dev;
> -	aux->dp_aux.transfer = dp_aux_transfer;
> -	ret = drm_dp_aux_register(&aux->dp_aux);
> +	ret = drm_dp_aux_register(dp_aux);
>   	if (ret) {
>   		DRM_ERROR("%s: failed to register drm aux: %d\n", __func__,
>   				ret);
> @@ -507,6 +501,21 @@ void dp_aux_unregister(struct drm_dp_aux *dp_aux)
>   	drm_dp_aux_unregister(dp_aux);
>   }
>   
> +static int dp_wait_hpd_asserted(struct drm_dp_aux *dp_aux,
> +				 unsigned long wait_us)
> +{
> +	int ret;
> +	struct dp_aux_private *aux;
> +
> +	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
> +
> +	pm_runtime_get_sync(aux->dev);
> +	ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog);
> +	pm_runtime_put_sync(aux->dev);
> +
> +	return ret;
> +}
> +
>   struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
>   			      bool is_edp)
>   {
> @@ -530,6 +539,17 @@ struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
>   	aux->catalog = catalog;
>   	aux->retry_cnt = 0;
>   
> +	/*
> +	 * Use the drm_dp_aux_init() to use the aux adapter
> +	 * before registering AUX with the DRM device so that
> +	 * msm eDP panel can be detected by generic_dep_panel_probe().
> +	 */
> +	aux->dp_aux.name = "dpu_dp_aux";
> +	aux->dp_aux.dev = dev;
> +	aux->dp_aux.transfer = dp_aux_transfer;
> +	aux->dp_aux.wait_hpd_asserted = dp_wait_hpd_asserted;
> +	drm_dp_aux_init(&aux->dp_aux);
> +
>   	return &aux->dp_aux;
>   }
>   
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index 79e56d9..df15145 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -1207,6 +1207,17 @@ static const struct msm_dp_desc *dp_display_get_desc(struct platform_device *pde
>   	return NULL;
>   }
>   
> +static int dp_auxbus_done_probe(struct drm_dp_aux *aux)
> +{
> +	int rc;
> +
> +	rc = component_add(aux->dev, &dp_display_comp_ops);
> +	if (rc)
> +		DRM_ERROR("eDP component add failed, rc=%d\n", rc);
> +
> +	return rc;
> +}
> +
>   static int dp_display_probe(struct platform_device *pdev)
>   {
>   	int rc = 0;
> @@ -1272,10 +1283,18 @@ static int dp_display_probe(struct platform_device *pdev)
>   	if (rc)
>   		goto err;
>   
> -	rc = component_add(&pdev->dev, &dp_display_comp_ops);
> -	if (rc) {
> -		DRM_ERROR("component add failed, rc=%d\n", rc);
> -		goto err;
> +	if (dp->dp_display.is_edp) {
> +		rc = devm_of_dp_aux_populate_bus(dp->aux, dp_auxbus_done_probe);
> +		if (rc) {
> +			DRM_ERROR("eDP auxbus population failed, rc=%d\n", rc);
> +			goto err;
> +		}
> +	} else {
> +		rc = component_add(&pdev->dev, &dp_display_comp_ops);
> +		if (rc) {
> +			DRM_ERROR("component add failed, rc=%d\n", rc);
> +			goto err;
> +		}
>   	}
>   
>   	return rc;
> @@ -1291,7 +1310,6 @@ static int dp_display_remove(struct platform_device *pdev)
>   
>   	component_del(&pdev->dev, &dp_display_comp_ops);
>   	dp_display_deinit_sub_modules(dp);
> -

Nit: irrelevant to this patch.

>   	platform_set_drvdata(pdev, NULL);
>   
>   	return 0;
> @@ -1388,29 +1406,8 @@ static int dp_display_get_next_bridge(struct msm_dp *dp)
>   {
>   	int rc;
>   	struct dp_display_private *dp_priv;
> -	struct device_node *aux_bus;
> -	struct device *dev;
>   
>   	dp_priv = container_of(dp, struct dp_display_private, dp_display);
> -	dev = &dp_priv->pdev->dev;
> -	aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
> -
> -	if (aux_bus && dp->is_edp) {
> -		/*
> -		 * The code below assumes that the panel will finish probing
> -		 * by the time devm_of_dp_aux_populate_ep_devices() returns.
> -		 * This isn't a great assumption since it will fail if the
> -		 * panel driver is probed asynchronously but is the best we
> -		 * can do without a bigger driver reorganization.
> -		 */
> -		rc = of_dp_aux_populate_bus(dp_priv->aux, NULL);
> -		of_node_put(aux_bus);
> -		if (rc)
> -			goto error;
> -	} else if (dp->is_edp) {
> -		DRM_ERROR("eDP aux_bus not found\n");
> -		return -ENODEV;
> -	}
>   
>   	/*
>   	 * External bridges are mandatory for eDP interfaces: one has to
> @@ -1423,17 +1420,9 @@ static int dp_display_get_next_bridge(struct msm_dp *dp)
>   	if (!dp->is_edp && rc == -ENODEV)
>   		return 0;
>   
> -	if (!rc) {
> +	if (!rc)
>   		dp->next_bridge = dp_priv->parser->next_bridge;
> -		return 0;
> -	}
>   
> -error:
> -	if (dp->is_edp) {
> -		of_dp_aux_depopulate_bus(dp_priv->aux);
> -		dp_display_host_phy_exit(dp_priv);
> -		dp_display_host_deinit(dp_priv);
> -	}
>   	return rc;
>   }
>   

-- 
With best wishes
Dmitry