[PATCH] drm/bridge: adv7511: Attach to DSI host at probe time

[PATCH] drm/bridge: adv7511: Attach to DSI host at probe time

[Matt Redfearn]

In contrast to all of the DSI panel drivers in drivers/gpu/drm/panel
which attach to the DSI host via mipi_dsi_attach() at probe time, the
ADV7533 bridge device does not. Instead it defers this to the point that
the upstream device connects to its bridge via drm_bridge_attach().
The generic Synopsys MIPI DSI host driver does not register it's own
drm_bridge until the MIPI DSI has attached. But it does not call
drm_bridge_attach() on the downstream device until the upstream device
has attached. This leads to a chicken and the egg failure and the DRM
pipeline does not complete.
Since all other mipi_dsi_device drivers call mipi_dsi_attach() in
probe(), make the adv7533 mipi_dsi_device do the same. This ensures that
the Synopsys MIPI DSI host registers it's bridge such that it is
available for the upstream device to connect to.

Signed-off-by: Matt Redfearn <matt.redfearn@thinci.com>

---

 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index e7ddd3e3db9..ea36ac3a3de 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -874,9 +874,6 @@ static int adv7511_bridge_attach(struct drm_bridge *bridge)
 				 &adv7511_connector_helper_funcs);
 	drm_connector_attach_encoder(&adv->connector, bridge->encoder);
 
-	if (adv->type == ADV7533)
-		ret = adv7533_attach_dsi(adv);
-
 	if (adv->i2c_main->irq)
 		regmap_write(adv->regmap, ADV7511_REG_INT_ENABLE(0),
 			     ADV7511_INT0_HPD);
@@ -1222,7 +1219,11 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
 	drm_bridge_add(&adv7511->bridge);
 
 	adv7511_audio_init(dev, adv7511);
-	return 0;
+
+	if (adv7511->type == ADV7533)
+		return adv7533_attach_dsi(adv7511);
+	else
+		return 0;
 
 err_unregister_cec:
 	i2c_unregister_device(adv7511->i2c_cec);
-- 
2.17.1

Re: [PATCH] drm/bridge: adv7511: Attach to DSI host at probe time

[Matt Redfearn]

Hi,

Any feedback on this patch?

Thanks,
Matt

On 24/04/2019 14:22, Matthew Redfearn wrote:
> In contrast to all of the DSI panel drivers in drivers/gpu/drm/panel
> which attach to the DSI host via mipi_dsi_attach() at probe time, the
> ADV7533 bridge device does not. Instead it defers this to the point that
> the upstream device connects to its bridge via drm_bridge_attach().
> The generic Synopsys MIPI DSI host driver does not register it's own
> drm_bridge until the MIPI DSI has attached. But it does not call
> drm_bridge_attach() on the downstream device until the upstream device
> has attached. This leads to a chicken and the egg failure and the DRM
> pipeline does not complete.
> Since all other mipi_dsi_device drivers call mipi_dsi_attach() in
> probe(), make the adv7533 mipi_dsi_device do the same. This ensures that
> the Synopsys MIPI DSI host registers it's bridge such that it is
> available for the upstream device to connect to.
> 
> Signed-off-by: Matt Redfearn <matt.redfearn@thinci.com>
> 
> ---
> 
>   drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> index e7ddd3e3db9..ea36ac3a3de 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> @@ -874,9 +874,6 @@ static int adv7511_bridge_attach(struct drm_bridge *bridge)
>   				 &adv7511_connector_helper_funcs);
>   	drm_connector_attach_encoder(&adv->connector, bridge->encoder);
>   
> -	if (adv->type == ADV7533)
> -		ret = adv7533_attach_dsi(adv);
> -
>   	if (adv->i2c_main->irq)
>   		regmap_write(adv->regmap, ADV7511_REG_INT_ENABLE(0),
>   			     ADV7511_INT0_HPD);
> @@ -1222,7 +1219,11 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
>   	drm_bridge_add(&adv7511->bridge);
>   
>   	adv7511_audio_init(dev, adv7511);
> -	return 0;
> +
> +	if (adv7511->type == ADV7533)
> +		return adv7533_attach_dsi(adv7511);
> +	else
> +		return 0;
>   
>   err_unregister_cec:
>   	i2c_unregister_device(adv7511->i2c_cec);
> 

Re: [PATCH] drm/bridge: adv7511: Attach to DSI host at probe time

[Andrzej Hajda]

On 24.04.2019 15:22, Matt Redfearn wrote:
> In contrast to all of the DSI panel drivers in drivers/gpu/drm/panel
> which attach to the DSI host via mipi_dsi_attach() at probe time, the
> ADV7533 bridge device does not. Instead it defers this to the point that
> the upstream device connects to its bridge via drm_bridge_attach().
> The generic Synopsys MIPI DSI host driver does not register it's own
> drm_bridge until the MIPI DSI has attached. But it does not call
> drm_bridge_attach() on the downstream device until the upstream device
> has attached. This leads to a chicken and the egg failure and the DRM
> pipeline does not complete.
> Since all other mipi_dsi_device drivers call mipi_dsi_attach() in
> probe(), make the adv7533 mipi_dsi_device do the same. This ensures that
> the Synopsys MIPI DSI host registers it's bridge such that it is
> available for the upstream device to connect to.
>
> Signed-off-by: Matt Redfearn <matt.redfearn@thinci.com>
>
> ---
>
>  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> index e7ddd3e3db9..ea36ac3a3de 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> @@ -874,9 +874,6 @@ static int adv7511_bridge_attach(struct drm_bridge *bridge)
>  				 &adv7511_connector_helper_funcs);
>  	drm_connector_attach_encoder(&adv->connector, bridge->encoder);
>  
> -	if (adv->type == ADV7533)
> -		ret = adv7533_attach_dsi(adv);
> -
>  	if (adv->i2c_main->irq)
>  		regmap_write(adv->regmap, ADV7511_REG_INT_ENABLE(0),
>  			     ADV7511_INT0_HPD);
> @@ -1222,7 +1219,11 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
>  	drm_bridge_add(&adv7511->bridge);
>  
>  	adv7511_audio_init(dev, adv7511);
> -	return 0;
> +
> +	if (adv7511->type == ADV7533)
> +		return adv7533_attach_dsi(adv7511);
> +	else
> +		return 0;


It seems that on failure of adv7533_attach_dsi cleanup is not performed.

Beside this change looks OK, but it would be good to test it on
platforms with adv7533.


Regards

Andrzej


>  
>  err_unregister_cec:
>  	i2c_unregister_device(adv7511->i2c_cec);

Re: [PATCH] drm/bridge: adv7511: Attach to DSI host at probe time

[Matt Redfearn]

On 25/06/2019 11:54, Andrzej Hajda wrote:
> On 24.04.2019 15:22, Matt Redfearn wrote:
>> In contrast to all of the DSI panel drivers in drivers/gpu/drm/panel
>> which attach to the DSI host via mipi_dsi_attach() at probe time, the
>> ADV7533 bridge device does not. Instead it defers this to the point that
>> the upstream device connects to its bridge via drm_bridge_attach().
>> The generic Synopsys MIPI DSI host driver does not register it's own
>> drm_bridge until the MIPI DSI has attached. But it does not call
>> drm_bridge_attach() on the downstream device until the upstream device
>> has attached. This leads to a chicken and the egg failure and the DRM
>> pipeline does not complete.
>> Since all other mipi_dsi_device drivers call mipi_dsi_attach() in
>> probe(), make the adv7533 mipi_dsi_device do the same. This ensures that
>> the Synopsys MIPI DSI host registers it's bridge such that it is
>> available for the upstream device to connect to.
>>
>> Signed-off-by: Matt Redfearn <matt.redfearn@thinci.com>
>>
>> ---
>>
>>   drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 9 +++++----
>>   1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> index e7ddd3e3db9..ea36ac3a3de 100644
>> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> @@ -874,9 +874,6 @@ static int adv7511_bridge_attach(struct drm_bridge *bridge)
>>   				 &adv7511_connector_helper_funcs);
>>   	drm_connector_attach_encoder(&adv->connector, bridge->encoder);
>>   
>> -	if (adv->type == ADV7533)
>> -		ret = adv7533_attach_dsi(adv);
>> -
>>   	if (adv->i2c_main->irq)
>>   		regmap_write(adv->regmap, ADV7511_REG_INT_ENABLE(0),
>>   			     ADV7511_INT0_HPD);
>> @@ -1222,7 +1219,11 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
>>   	drm_bridge_add(&adv7511->bridge);
>>   
>>   	adv7511_audio_init(dev, adv7511);
>> -	return 0;
>> +
>> +	if (adv7511->type == ADV7533)
>> +		return adv7533_attach_dsi(adv7511);
>> +	else
>> +		return 0;
> 
> 
> It seems that on failure of adv7533_attach_dsi cleanup is not performed.

Hi Andrzej,
Quite right - I will fix and resend.

> 
> Beside this change looks OK, but it would be good to test it on
> platforms with adv7533.

As in the commit message, I needed this change to get the driver to work 
at all on a platform with a Synopsys MIPI DSI interface. However I would 
be very grateful for feedback from people using the ADV7533 with other 
MIPI DSI hosts.

Thanks,
Matt

> 
> 
> Regards
> 
> Andrzej
> 
> 
>>   
>>   err_unregister_cec:
>>   	i2c_unregister_device(adv7511->i2c_cec);
> 
>