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Subject: Re: [PATCH] drm: bridge: rename the function drm_bridge_hpd_notify to
 drm_bridge_hpd_cb
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        kernel@collabora.com, dafna3@gmail.com, airlied@linux.ie,
        daniel@ffwll.ch, enric.balletbo@collabora.com
References: <20210330115200.26006-1-dafna.hirschfeld@collabora.com>
 <YGxWwTTjhFcVDELB@pendragon.ideasonboard.com>
From:   Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Message-ID: <284cd4e3-b6a9-0b48-a01d-86d22f4f2e23@collabora.com>
Date:   Wed, 7 Apr 2021 17:26:18 +0200
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Hi

On 06.04.21 14:40, Laurent Pinchart wrote:
> Hi Dafna,
> 
> Thank you for the patch.
> 
> On Tue, Mar 30, 2021 at 01:52:00PM +0200, Dafna Hirschfeld wrote:
>> drm_bridge_funcs has a function called 'hpd_notify'.
>> The function drm_bridge_hpd_notify does not call
>> 'hpd_notify' but it calls 'hpd_cb'. This is rather
>> confusing. Rename the function to fix this confusion.
>>
>> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
>> ---
>>   drivers/gpu/drm/bridge/adv7511/adv7511_drv.c        | 2 +-
>>   drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 4 ++--
>>   drivers/gpu/drm/bridge/display-connector.c          | 2 +-
>>   drivers/gpu/drm/bridge/lontium-lt9611uxc.c          | 8 ++++----
>>   drivers/gpu/drm/bridge/synopsys/dw-hdmi.c           | 2 +-
>>   drivers/gpu/drm/bridge/ti-tpd12s015.c               | 2 +-
>>   drivers/gpu/drm/drm_bridge.c                        | 8 ++++----
>>   include/drm/drm_bridge.h                            | 8 ++++----
>>   8 files changed, 18 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> index 76555ae64e9c..748f82910f4f 100644
>> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> @@ -449,7 +449,7 @@ static void adv7511_hpd_work(struct work_struct *work)
>>   				cec_phys_addr_invalidate(adv7511->cec_adap);
>>   			drm_kms_helper_hotplug_event(adv7511->connector.dev);
>>   		} else {
>> -			drm_bridge_hpd_notify(&adv7511->bridge, status);
>> +			drm_bridge_hpd_cb(&adv7511->bridge, status);
>>   		}
>>   	}
>>   }
>> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
>> index d0c65610ebb5..682da288ff6d 100644
>> --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
>> +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
>> @@ -794,7 +794,7 @@ static void cdns_mhdp_fw_cb(const struct firmware *fw, void *context)
>>   		if (mhdp->connector.dev)
>>   			drm_kms_helper_hotplug_event(mhdp->bridge.dev);
>>   		else
>> -			drm_bridge_hpd_notify(&mhdp->bridge, cdns_mhdp_detect(mhdp));
>> +			drm_bridge_hpd_cb(&mhdp->bridge, cdns_mhdp_detect(mhdp));
>>   	}
>>   }
>>   
>> @@ -2314,7 +2314,7 @@ static irqreturn_t cdns_mhdp_irq_handler(int irq, void *data)
>>   			else
>>   				drm_kms_helper_hotplug_event(mhdp->bridge.dev);
>>   		} else {
>> -			drm_bridge_hpd_notify(&mhdp->bridge, cdns_mhdp_detect(mhdp));
>> +			drm_bridge_hpd_cb(&mhdp->bridge, cdns_mhdp_detect(mhdp));
>>   		}
>>   	}
>>   
>> diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/bridge/display-connector.c
>> index 05eb759da6fc..8ccd69d7fe34 100644
>> --- a/drivers/gpu/drm/bridge/display-connector.c
>> +++ b/drivers/gpu/drm/bridge/display-connector.c
>> @@ -98,7 +98,7 @@ static irqreturn_t display_connector_hpd_irq(int irq, void *arg)
>>   	struct display_connector *conn = arg;
>>   	struct drm_bridge *bridge = &conn->bridge;
>>   
>> -	drm_bridge_hpd_notify(bridge, display_connector_detect(bridge));
>> +	drm_bridge_hpd_cb(bridge, display_connector_detect(bridge));
>>   
>>   	return IRQ_HANDLED;
>>   }
>> diff --git a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
>> index fee27952ec6d..58f61b5da605 100644
>> --- a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
>> +++ b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
>> @@ -175,10 +175,10 @@ static void lt9611uxc_hpd_work(struct work_struct *work)
>>   		connected = lt9611uxc->hdmi_connected;
>>   		mutex_unlock(&lt9611uxc->ocm_lock);
>>   
>> -		drm_bridge_hpd_notify(&lt9611uxc->bridge,
>> -				      connected ?
>> -				      connector_status_connected :
>> -				      connector_status_disconnected);
>> +		drm_bridge_hpd_cb(&lt9611uxc->bridge,
>> +				  connected ?
>> +				  connector_status_connected :
>> +				  connector_status_disconnected);
>>   	}
>>   }
>>   
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> index dda4fa9a1a08..984ab5c4bc71 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> @@ -3026,7 +3026,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
>>   
>>   		if (hdmi->bridge.dev) {
>>   			drm_helper_hpd_irq_event(hdmi->bridge.dev);
>> -			drm_bridge_hpd_notify(&hdmi->bridge, status);
>> +			drm_bridge_hpd_cb(&hdmi->bridge, status);
>>   		}
>>   	}
>>   
>> diff --git a/drivers/gpu/drm/bridge/ti-tpd12s015.c b/drivers/gpu/drm/bridge/ti-tpd12s015.c
>> index e0e015243a60..2f079b6f51bc 100644
>> --- a/drivers/gpu/drm/bridge/ti-tpd12s015.c
>> +++ b/drivers/gpu/drm/bridge/ti-tpd12s015.c
>> @@ -103,7 +103,7 @@ static irqreturn_t tpd12s015_hpd_isr(int irq, void *data)
>>   	struct tpd12s015_device *tpd = data;
>>   	struct drm_bridge *bridge = &tpd->bridge;
>>   
>> -	drm_bridge_hpd_notify(bridge, tpd12s015_detect(bridge));
>> +	drm_bridge_hpd_cb(bridge, tpd12s015_detect(bridge));
>>   
>>   	return IRQ_HANDLED;
>>   }
>> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
>> index 64f0effb52ac..653761a0d5f9 100644
>> --- a/drivers/gpu/drm/drm_bridge.c
>> +++ b/drivers/gpu/drm/drm_bridge.c
>> @@ -1173,7 +1173,7 @@ void drm_bridge_hpd_disable(struct drm_bridge *bridge)
>>   EXPORT_SYMBOL_GPL(drm_bridge_hpd_disable);
>>   
>>   /**
>> - * drm_bridge_hpd_notify - notify hot plug detection events
>> + * drm_bridge_hpd_cb - notify hot plug detection events
> 
> This function is still documented as notifying hot plug detection
> events, so drm_bridge_hpd_cb() isn't a great name :-S I do agree there's
> confusion with the current naming scheme though.
> 
> bridge->hpd_cb() is an internal callback, not part of bridge ops, so I'd
> rather not expose its name in the public drm_bridge_hpd_notify() API.
> Could we find a better naming scheme ?

I that bridge->funcs->hpd_notify is called only from drm_bridge_connector_hpd_notify
which is called from both the hpd cb and from the 'detect' of the bridge connector.
But 'detect' is not necesseraly by hpd right? I mean there is other ways apart of hpd
to detect a connctor right?
If that is the case then bridge->funcs->hpd_notify is also not a good name.

Also, I see that in some places the function drm_bridge_connector_init
is called without later calling the function drm_bridge_connector_enable_hpd.
Is there a use case in which we want to create a bridge connector without enabeling
the hpd_cb ?

Regarding the naming, maybe we can replace 'drm_bridge_hpd_notify' with 'drm_bridge_hpd' ?

Thanks,
Dafna

> 
>>    * @bridge: bridge control structure
>>    * @status: output connection status
>>    *
>> @@ -1183,15 +1183,15 @@ EXPORT_SYMBOL_GPL(drm_bridge_hpd_disable);
>>    *
>>    * This function shall be called in a context that can sleep.
>>    */
>> -void drm_bridge_hpd_notify(struct drm_bridge *bridge,
>> -			   enum drm_connector_status status)
>> +void drm_bridge_hpd_cb(struct drm_bridge *bridge,
>> +		       enum drm_connector_status status)
>>   {
>>   	mutex_lock(&bridge->hpd_mutex);
>>   	if (bridge->hpd_cb)
>>   		bridge->hpd_cb(bridge->hpd_data, status);
>>   	mutex_unlock(&bridge->hpd_mutex);
>>   }
>> -EXPORT_SYMBOL_GPL(drm_bridge_hpd_notify);
>> +EXPORT_SYMBOL_GPL(drm_bridge_hpd_cb);
>>   
>>   #ifdef CONFIG_OF
>>   /**
>> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
>> index 2195daa289d2..ab54715eda8b 100644
>> --- a/include/drm/drm_bridge.h
>> +++ b/include/drm/drm_bridge.h
>> @@ -605,7 +605,7 @@ struct drm_bridge_funcs {
>>   	 * @hpd_enable:
>>   	 *
>>   	 * Enable hot plug detection. From now on the bridge shall call
>> -	 * drm_bridge_hpd_notify() each time a change is detected in the output
>> +	 * drm_bridge_hpd_cb() each time a change is detected in the output
>>   	 * connection status, until hot plug detection gets disabled with
>>   	 * @hpd_disable.
>>   	 *
>> @@ -620,7 +620,7 @@ struct drm_bridge_funcs {
>>   	 * @hpd_disable:
>>   	 *
>>   	 * Disable hot plug detection. Once this function returns the bridge
>> -	 * shall not call drm_bridge_hpd_notify() when a change in the output
>> +	 * shall not call drm_bridge_hpd_cb() when a change in the output
>>   	 * connection status occurs.
>>   	 *
>>   	 * This callback is optional and shall only be implemented by bridges
>> @@ -878,8 +878,8 @@ void drm_bridge_hpd_enable(struct drm_bridge *bridge,
>>   				      enum drm_connector_status status),
>>   			   void *data);
>>   void drm_bridge_hpd_disable(struct drm_bridge *bridge);
>> -void drm_bridge_hpd_notify(struct drm_bridge *bridge,
>> -			   enum drm_connector_status status);
>> +void drm_bridge_hpd_cb(struct drm_bridge *bridge,
>> +		       enum drm_connector_status status);
>>   
>>   #ifdef CONFIG_DRM_PANEL_BRIDGE
>>   struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel);
>