[3/5] drm/bridge: simple-bridge: Allow acquiring the next bridge with fwnode API

  Which make it possible to use this driver on non-DT based systems,
meanwhile, made no functional changes for DT based systems.

Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
---
 drivers/gpu/drm/bridge/simple-bridge.c | 51 ++++++++++++++++++++++----
 1 file changed, 44 insertions(+), 7 deletions(-)
  

On Tue, Jan 23, 2024 at 12:32:18AM +0800, Sui Jingfeng wrote:
> Which make it possible to use this driver on non-DT based systems,
> meanwhile, made no functional changes for DT based systems.
> 
> Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
> ---
>  drivers/gpu/drm/bridge/simple-bridge.c | 51 ++++++++++++++++++++++----
>  1 file changed, 44 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
> index 595f672745b9..cfea5a67cc5b 100644
> --- a/drivers/gpu/drm/bridge/simple-bridge.c
> +++ b/drivers/gpu/drm/bridge/simple-bridge.c
> @@ -184,6 +184,39 @@ static const void *simple_bridge_get_match_data(const struct device *dev)
>  	return NULL;
>  }
>  
> +static int simple_bridge_get_next_bridge_by_fwnode(struct device *dev,
> +						   struct drm_bridge **next_bridge)
> +{
> +	struct drm_bridge *bridge;
> +	struct fwnode_handle *ep;
> +	struct fwnode_handle *remote;
> +
> +	ep = fwnode_graph_get_endpoint_by_id(dev->fwnode, 1, 0, 0);
> +	if (!ep) {
> +		dev_err(dev, "The endpoint is unconnected\n");
> +		return -EINVAL;
> +	}
> +
> +	remote = fwnode_graph_get_remote_port_parent(ep);
> +	fwnode_handle_put(ep);
> +	if (!remote) {
> +		dev_err(dev, "No valid remote node\n");
> +		return -ENODEV;
> +	}
> +
> +	bridge = drm_bridge_find_by_fwnode(remote);
> +	fwnode_handle_put(remote);
> +
> +	if (!bridge) {
> +		dev_warn(dev, "Next bridge not found, deferring probe\n");
> +		return -EPROBE_DEFER;
> +	}
> +
> +	*next_bridge = bridge;
> +
> +	return 0;
> +}
> +

Hmmmm yes, this convinces me further that we should switch to fwnode,
not implement fwnode and OF side-by-side.

>  static int simple_bridge_probe(struct platform_device *pdev)
>  {
>  	struct simple_bridge *sbridge;
> @@ -199,14 +232,17 @@ static int simple_bridge_probe(struct platform_device *pdev)
>  	else
>  		sbridge->info = simple_bridge_get_match_data(&pdev->dev);
>  
> -	/* Get the next bridge in the pipeline. */
> -	remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1);
> -	if (!remote)
> -		return -EINVAL;
> -
> -	sbridge->next_bridge = of_drm_find_bridge(remote);
> -	of_node_put(remote);
> +	if (pdev->dev.of_node) {
> +		/* Get the next bridge in the pipeline. */
> +		remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1);
> +		if (!remote)
> +			return -EINVAL;
>  
> +		sbridge->next_bridge = of_drm_find_bridge(remote);
> +		of_node_put(remote);
> +	} else {
> +		simple_bridge_get_next_bridge_by_fwnode(&pdev->dev, &sbridge->next_bridge);
> +	}
>  	if (!sbridge->next_bridge) {
>  		dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n");
>  		return -EPROBE_DEFER;
> @@ -231,6 +267,7 @@ static int simple_bridge_probe(struct platform_device *pdev)
>  	/* Register the bridge. */
>  	sbridge->bridge.funcs = &simple_bridge_bridge_funcs;
>  	sbridge->bridge.of_node = pdev->dev.of_node;
> +	sbridge->bridge.fwnode = pdev->dev.fwnode;
>  	sbridge->bridge.timings = sbridge->info->timings;
>  
>  	drm_bridge_add(&sbridge->bridge);
> -- 
> 2.25.1
>
  

Hi,


On 2024/1/23 09:18, Laurent Pinchart wrote:
> On Tue, Jan 23, 2024 at 12:32:18AM +0800, Sui Jingfeng wrote:
>> Which make it possible to use this driver on non-DT based systems,
>> meanwhile, made no functional changes for DT based systems.
>>
>> Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
>> ---
>>   drivers/gpu/drm/bridge/simple-bridge.c | 51 ++++++++++++++++++++++----
>>   1 file changed, 44 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
>> index 595f672745b9..cfea5a67cc5b 100644
>> --- a/drivers/gpu/drm/bridge/simple-bridge.c
>> +++ b/drivers/gpu/drm/bridge/simple-bridge.c
>> @@ -184,6 +184,39 @@ static const void *simple_bridge_get_match_data(const struct device *dev)
>>   	return NULL;
>>   }
>>   
>> +static int simple_bridge_get_next_bridge_by_fwnode(struct device *dev,
>> +						   struct drm_bridge **next_bridge)
>> +{
>> +	struct drm_bridge *bridge;
>> +	struct fwnode_handle *ep;
>> +	struct fwnode_handle *remote;
>> +
>> +	ep = fwnode_graph_get_endpoint_by_id(dev->fwnode, 1, 0, 0);
>> +	if (!ep) {
>> +		dev_err(dev, "The endpoint is unconnected\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	remote = fwnode_graph_get_remote_port_parent(ep);
>> +	fwnode_handle_put(ep);
>> +	if (!remote) {
>> +		dev_err(dev, "No valid remote node\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	bridge = drm_bridge_find_by_fwnode(remote);
>> +	fwnode_handle_put(remote);
>> +
>> +	if (!bridge) {
>> +		dev_warn(dev, "Next bridge not found, deferring probe\n");
>> +		return -EPROBE_DEFER;
>> +	}
>> +
>> +	*next_bridge = bridge;
>> +
>> +	return 0;
>> +}
>> +
> Hmmmm yes, this convinces me further that we should switch to fwnode,
> not implement fwnode and OF side-by-side.
>

OK, I'm agree with you.


But this means that I have to make the drm_bridge_find_by_fwnode() function works
on both DT systems and non-DT systems. This is also means that we will no longer
need to call of_drm_find_bridge() function anymore. This will eventually lead to
completely remove of_drm_find_bridge()?


As far as I can see, if I follow you suggestion, drm/bridge subsystem will
encountering a *big* refactor. My 'side-by-side' approach allows co-exist.
It is not really meant to purge OF. I feel it is a little bit of aggressive.

hello Maxime, are you watching this? what do you think?


>>   static int simple_bridge_probe(struct platform_device *pdev)
>>   {
>>   	struct simple_bridge *sbridge;
>> @@ -199,14 +232,17 @@ static int simple_bridge_probe(struct platform_device *pdev)
>>   	else
>>   		sbridge->info = simple_bridge_get_match_data(&pdev->dev);
>>   
>> -	/* Get the next bridge in the pipeline. */
>> -	remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1);
>> -	if (!remote)
>> -		return -EINVAL;
>> -
>> -	sbridge->next_bridge = of_drm_find_bridge(remote);
>> -	of_node_put(remote);
>> +	if (pdev->dev.of_node) {
>> +		/* Get the next bridge in the pipeline. */
>> +		remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1);
>> +		if (!remote)
>> +			return -EINVAL;
>>   
>> +		sbridge->next_bridge = of_drm_find_bridge(remote);
>> +		of_node_put(remote);
>> +	} else {
>> +		simple_bridge_get_next_bridge_by_fwnode(&pdev->dev, &sbridge->next_bridge);
>> +	}
>>   	if (!sbridge->next_bridge) {
>>   		dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n");
>>   		return -EPROBE_DEFER;
>> @@ -231,6 +267,7 @@ static int simple_bridge_probe(struct platform_device *pdev)
>>   	/* Register the bridge. */
>>   	sbridge->bridge.funcs = &simple_bridge_bridge_funcs;
>>   	sbridge->bridge.of_node = pdev->dev.of_node;
>> +	sbridge->bridge.fwnode = pdev->dev.fwnode;
>>   	sbridge->bridge.timings = sbridge->info->timings;
>>   
>>   	drm_bridge_add(&sbridge->bridge);
>> -- 
>> 2.25.1
>>
  

Hello Sui,

On Tue, Jan 23, 2024 at 08:18:22PM +0800, Sui Jingfeng wrote:
> On 2024/1/23 09:18, Laurent Pinchart wrote:
> > On Tue, Jan 23, 2024 at 12:32:18AM +0800, Sui Jingfeng wrote:
> >> Which make it possible to use this driver on non-DT based systems,
> >> meanwhile, made no functional changes for DT based systems.
> >>
> >> Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
> >> ---
> >>   drivers/gpu/drm/bridge/simple-bridge.c | 51 ++++++++++++++++++++++----
> >>   1 file changed, 44 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
> >> index 595f672745b9..cfea5a67cc5b 100644
> >> --- a/drivers/gpu/drm/bridge/simple-bridge.c
> >> +++ b/drivers/gpu/drm/bridge/simple-bridge.c
> >> @@ -184,6 +184,39 @@ static const void *simple_bridge_get_match_data(const struct device *dev)
> >>   	return NULL;
> >>   }
> >>   
> >> +static int simple_bridge_get_next_bridge_by_fwnode(struct device *dev,
> >> +						   struct drm_bridge **next_bridge)
> >> +{
> >> +	struct drm_bridge *bridge;
> >> +	struct fwnode_handle *ep;
> >> +	struct fwnode_handle *remote;
> >> +
> >> +	ep = fwnode_graph_get_endpoint_by_id(dev->fwnode, 1, 0, 0);
> >> +	if (!ep) {
> >> +		dev_err(dev, "The endpoint is unconnected\n");
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	remote = fwnode_graph_get_remote_port_parent(ep);
> >> +	fwnode_handle_put(ep);
> >> +	if (!remote) {
> >> +		dev_err(dev, "No valid remote node\n");
> >> +		return -ENODEV;
> >> +	}
> >> +
> >> +	bridge = drm_bridge_find_by_fwnode(remote);
> >> +	fwnode_handle_put(remote);
> >> +
> >> +	if (!bridge) {
> >> +		dev_warn(dev, "Next bridge not found, deferring probe\n");
> >> +		return -EPROBE_DEFER;
> >> +	}
> >> +
> >> +	*next_bridge = bridge;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >
> > Hmmmm yes, this convinces me further that we should switch to fwnode,
> > not implement fwnode and OF side-by-side.
> 
> OK, I'm agree with you.
> 
> But this means that I have to make the drm_bridge_find_by_fwnode() function works
> on both DT systems and non-DT systems. This is also means that we will no longer
> need to call of_drm_find_bridge() function anymore. This will eventually lead to
> completely remove of_drm_find_bridge()?

It would be replaced by fwnode_drm_find_bridge(). Although, if we need
to rename the function, I think it would be best to make have a drm_
prefix, maybe drm_bridge_find-by_fwnode() or something similar.

> As far as I can see, if I follow you suggestion, drm/bridge subsystem will
> encountering a *big* refactor. My 'side-by-side' approach allows co-exist.
> It is not really meant to purge OF. I feel it is a little bit of aggressive.
> 
> hello Maxime, are you watching this? what do you think?
> 
> >>   static int simple_bridge_probe(struct platform_device *pdev)
> >>   {
> >>   	struct simple_bridge *sbridge;
> >> @@ -199,14 +232,17 @@ static int simple_bridge_probe(struct platform_device *pdev)
> >>   	else
> >>   		sbridge->info = simple_bridge_get_match_data(&pdev->dev);
> >>   
> >> -	/* Get the next bridge in the pipeline. */
> >> -	remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1);
> >> -	if (!remote)
> >> -		return -EINVAL;
> >> -
> >> -	sbridge->next_bridge = of_drm_find_bridge(remote);
> >> -	of_node_put(remote);
> >> +	if (pdev->dev.of_node) {
> >> +		/* Get the next bridge in the pipeline. */
> >> +		remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1);
> >> +		if (!remote)
> >> +			return -EINVAL;
> >>   
> >> +		sbridge->next_bridge = of_drm_find_bridge(remote);
> >> +		of_node_put(remote);
> >> +	} else {
> >> +		simple_bridge_get_next_bridge_by_fwnode(&pdev->dev, &sbridge->next_bridge);
> >> +	}
> >>   	if (!sbridge->next_bridge) {
> >>   		dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n");
> >>   		return -EPROBE_DEFER;
> >> @@ -231,6 +267,7 @@ static int simple_bridge_probe(struct platform_device *pdev)
> >>   	/* Register the bridge. */
> >>   	sbridge->bridge.funcs = &simple_bridge_bridge_funcs;
> >>   	sbridge->bridge.of_node = pdev->dev.of_node;
> >> +	sbridge->bridge.fwnode = pdev->dev.fwnode;
> >>   	sbridge->bridge.timings = sbridge->info->timings;
> >>   
> >>   	drm_bridge_add(&sbridge->bridge);
  

On Tue, Jan 23, 2024 at 08:18:22PM +0800, Sui Jingfeng wrote:
> Hi,
> 
> 
> On 2024/1/23 09:18, Laurent Pinchart wrote:
> > On Tue, Jan 23, 2024 at 12:32:18AM +0800, Sui Jingfeng wrote:
> > > Which make it possible to use this driver on non-DT based systems,
> > > meanwhile, made no functional changes for DT based systems.
> > > 
> > > Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
> > > ---
> > >   drivers/gpu/drm/bridge/simple-bridge.c | 51 ++++++++++++++++++++++----
> > >   1 file changed, 44 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
> > > index 595f672745b9..cfea5a67cc5b 100644
> > > --- a/drivers/gpu/drm/bridge/simple-bridge.c
> > > +++ b/drivers/gpu/drm/bridge/simple-bridge.c
> > > @@ -184,6 +184,39 @@ static const void *simple_bridge_get_match_data(const struct device *dev)
> > >   	return NULL;
> > >   }
> > > +static int simple_bridge_get_next_bridge_by_fwnode(struct device *dev,
> > > +						   struct drm_bridge **next_bridge)
> > > +{
> > > +	struct drm_bridge *bridge;
> > > +	struct fwnode_handle *ep;
> > > +	struct fwnode_handle *remote;
> > > +
> > > +	ep = fwnode_graph_get_endpoint_by_id(dev->fwnode, 1, 0, 0);
> > > +	if (!ep) {
> > > +		dev_err(dev, "The endpoint is unconnected\n");
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	remote = fwnode_graph_get_remote_port_parent(ep);
> > > +	fwnode_handle_put(ep);
> > > +	if (!remote) {
> > > +		dev_err(dev, "No valid remote node\n");
> > > +		return -ENODEV;
> > > +	}
> > > +
> > > +	bridge = drm_bridge_find_by_fwnode(remote);
> > > +	fwnode_handle_put(remote);
> > > +
> > > +	if (!bridge) {
> > > +		dev_warn(dev, "Next bridge not found, deferring probe\n");
> > > +		return -EPROBE_DEFER;
> > > +	}
> > > +
> > > +	*next_bridge = bridge;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > Hmmmm yes, this convinces me further that we should switch to fwnode,
> > not implement fwnode and OF side-by-side.
> > 
> 
> OK, I'm agree with you.
> 
> 
> But this means that I have to make the drm_bridge_find_by_fwnode() function works
> on both DT systems and non-DT systems. This is also means that we will no longer
> need to call of_drm_find_bridge() function anymore. This will eventually lead to
> completely remove of_drm_find_bridge()?
> 
> 
> As far as I can see, if I follow you suggestion, drm/bridge subsystem will
> encountering a *big* refactor. My 'side-by-side' approach allows co-exist.
> It is not really meant to purge OF. I feel it is a little bit of aggressive.
> 
> hello Maxime, are you watching this? what do you think?

It's indeed going to be a pretty big refactoring, but I agree with
Laurent that we don't want to maintain both side by side.

Maxime