linux-kernel - Re: [PATCH 2/5] drm/bridge: simple-bridge: Extend match support for non-DT based systems

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Message-ID: <20240123012139.GD22880@pendragon.ideasonboard.com>
Date: Tue, 23 Jan 2024 03:21:39 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Sui Jingfeng <sui.jingfeng@...ux.dev>
Cc: David Airlie <airlied@...il.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	Daniel Vetter <daniel@...ll.ch>, dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/5] drm/bridge: simple-bridge: Extend match support for
 non-DT based systems

On Tue, Jan 23, 2024 at 12:32:17AM +0800, Sui Jingfeng wrote:
> Which is intended to be used on non-DT environment, where the simple-bridge
> platform device is created by either the display controller driver side or
> platform firmware subsystem.

Could you give an example of a platform where you intend to use this ?

> To avoid duplication and to keep consistent,
> we choose to reuse the OF match tables. Because the potentional user may
> not has a of_node attached, nor a ACPI match id. If this is the case,
> a software node string property can be provide to fill the niche.

Shouldn't non-DT, non-ACPI platforms use swnodes ?

> Signed-off-by: Sui Jingfeng <sui.jingfeng@...ux.dev>
> ---
>  drivers/gpu/drm/bridge/simple-bridge.c | 24 +++++++++++++++++++++++-
>  1 file changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
> index cbe8e778d7c7..595f672745b9 100644
> --- a/drivers/gpu/drm/bridge/simple-bridge.c
> +++ b/drivers/gpu/drm/bridge/simple-bridge.c
> @@ -166,6 +166,24 @@ static const struct drm_bridge_funcs simple_bridge_bridge_funcs = {
>  	.disable	= simple_bridge_disable,
>  };
>  
> +static const void *simple_bridge_get_match_data(const struct device *dev)
> +{
> +	const struct of_device_id *matches = dev->driver->of_match_table;
> +
> +	/* Try to get the match data by software node */
> +	while (matches) {
> +		if (!matches->compatible[0])
> +			break;
> +
> +		if (device_is_compatible(dev, matches->compatible))
> +			return matches->data;
> +
> +		matches++;
> +	}
> +
> +	return NULL;
> +}
> +
>  static int simple_bridge_probe(struct platform_device *pdev)
>  {
>  	struct simple_bridge *sbridge;
> @@ -176,7 +194,10 @@ static int simple_bridge_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  	platform_set_drvdata(pdev, sbridge);
>  
> -	sbridge->info = of_device_get_match_data(&pdev->dev);
> +	if (pdev->dev.of_node)
> +		sbridge->info = of_device_get_match_data(&pdev->dev);
> +	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);
> @@ -309,3 +330,4 @@ module_platform_driver(simple_bridge_driver);
>  MODULE_AUTHOR("Maxime Ripard <maxime.ripard@...e-electrons.com>");
>  MODULE_DESCRIPTION("Simple DRM bridge driver");
>  MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:simple-bridge");

This is an unrelated change.

-- 
Regards,

Laurent Pinchart