linux-kernel - Re: [PATCH v5 11/20] drm/bridge: analogix_dp: Add support to get panel from the DP AUX bus

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Message-ID: <v3is3v3fpx42i2eh2qrfkx3qx3z7iema3honi544qoc4j2whdo@h6ajv5h53gry>
Date: Thu, 9 Jan 2025 14:45:32 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Damon Ding <damon.ding@...k-chips.com>
Cc: heiko@...ech.de, robh@...nel.org, krzk+dt@...nel.org, 
	conor+dt@...nel.org, rfoss@...nel.org, vkoul@...nel.org, 
	sebastian.reichel@...labora.com, cristian.ciocaltea@...labora.com, l.stach@...gutronix.de, 
	andy.yan@...k-chips.com, hjc@...k-chips.com, algea.cao@...k-chips.com, 
	kever.yang@...k-chips.com, dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-phy@...ts.infradead.org
Subject: Re: [PATCH v5 11/20] drm/bridge: analogix_dp: Add support to get
 panel from the DP AUX bus

On Thu, Jan 09, 2025 at 11:27:16AM +0800, Damon Ding wrote:
> The main modification is moving the DP AUX initialization from function
> analogix_dp_bind() to analogix_dp_probe(). In order to get the EDID of
> eDP panel during probing, it is also needed to advance PM operaions to
> ensure that eDP controller and phy are prepared for AUX transmission.
> 
> Signed-off-by: Damon Ding <damon.ding@...k-chips.com>
> 
> ---
> 
> Changes in v4:
> - Use done_probing() to call drm_of_find_panel_or_bridge() and
>   component_add() when getting panel from the DP AUX bus
> 
> Changes in v5:
> - Advance PM operations to make eDP AUX work well
> ---
>  .../drm/bridge/analogix/analogix_dp_core.c    | 62 ++++++++++---------
>  1 file changed, 34 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 8251adfce2f9..78e78fb474d3 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1548,6 +1548,18 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux,
>  	return ret;
>  }
>  
> +static void analogix_dp_runtime_disable(void *data)
> +{
> +	struct analogix_dp_device *dp = (struct analogix_dp_device *)data;
> +
> +	if (IS_ENABLED(CONFIG_PM)) {
> +		pm_runtime_dont_use_autosuspend(dp->dev);
> +		pm_runtime_disable(dp->dev);
> +	} else {
> +		analogix_dp_suspend(dp);
> +	}
> +}
> +
>  struct analogix_dp_device *
>  analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>  {
> @@ -1658,8 +1670,29 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>  	}
>  	disable_irq(dp->irq);
>  
> +	dp->aux.name = "DP-AUX";
> +	dp->aux.transfer = analogix_dpaux_transfer;
> +	dp->aux.dev = dp->dev;
> +	drm_dp_aux_init(&dp->aux);
> +
> +	if (IS_ENABLED(CONFIG_PM)) {
> +		pm_runtime_use_autosuspend(dp->dev);
> +		pm_runtime_set_autosuspend_delay(dp->dev, 100);
> +		pm_runtime_enable(dp->dev);
> +	} else {
> +		ret = analogix_dp_resume(dp);
> +		if (ret)
> +			goto err_disable_clk;
> +	}
> +
> +	ret = devm_add_action_or_reset(dev, analogix_dp_runtime_disable, dp);

This looks like a local version of devm_pm_runtime_enable()

> +	if (ret)
> +		goto err_disable_pm_runtime;
> +
>  	return dp;
>  
> +err_disable_pm_runtime:
> +	analogix_dp_runtime_disable((void *)dp);
>  err_disable_clk:
>  	clk_disable_unprepare(dp->clock);
>  	return ERR_PTR(ret);
> @@ -1708,25 +1741,12 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
>  	dp->drm_dev = drm_dev;
>  	dp->encoder = dp->plat_data->encoder;
>  
> -	if (IS_ENABLED(CONFIG_PM)) {
> -		pm_runtime_use_autosuspend(dp->dev);
> -		pm_runtime_set_autosuspend_delay(dp->dev, 100);
> -		pm_runtime_enable(dp->dev);
> -	} else {
> -		ret = analogix_dp_resume(dp);
> -		if (ret)
> -			return ret;
> -	}
> -
> -	dp->aux.name = "DP-AUX";
> -	dp->aux.transfer = analogix_dpaux_transfer;
> -	dp->aux.dev = dp->dev;
>  	dp->aux.drm_dev = drm_dev;
>  
>  	ret = drm_dp_aux_register(&dp->aux);
>  	if (ret) {
>  		DRM_ERROR("failed to register AUX (%d)\n", ret);
> -		goto err_disable_pm_runtime;
> +		return ret;
>  	}
>  
>  	ret = analogix_dp_create_bridge(drm_dev, dp);
> @@ -1739,13 +1759,6 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
>  
>  err_unregister_aux:
>  	drm_dp_aux_unregister(&dp->aux);
> -err_disable_pm_runtime:
> -	if (IS_ENABLED(CONFIG_PM)) {
> -		pm_runtime_dont_use_autosuspend(dp->dev);
> -		pm_runtime_disable(dp->dev);
> -	} else {
> -		analogix_dp_suspend(dp);
> -	}
>  
>  	return ret;
>  }
> @@ -1762,13 +1775,6 @@ void analogix_dp_unbind(struct analogix_dp_device *dp)
>  	}
>  
>  	drm_dp_aux_unregister(&dp->aux);
> -
> -	if (IS_ENABLED(CONFIG_PM)) {
> -		pm_runtime_dont_use_autosuspend(dp->dev);
> -		pm_runtime_disable(dp->dev);
> -	} else {
> -		analogix_dp_suspend(dp);
> -	}
>  }
>  EXPORT_SYMBOL_GPL(analogix_dp_unbind);
>  
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry