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: <b028f794-bdc9-4414-a823-662ef2fd0ee1@rock-chips.com>
Date: Wed, 22 Jan 2025 16:06:33 +0800
From: Damon Ding <damon.ding@...k-chips.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
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

Hi Dmitry,

On 2025/1/9 20:45, Dmitry Baryshkov wrote:
> 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()
> 

Indeed, it is better to use devm_pm_runtime_enable() instead.

>> +	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
>>
> 

Best regards,
Damon