linux-kernel - Re: [PATCH v4 6/9] drm-bridge: sii902x: Use fwnode API to acquire device properties

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Message-ID: <nv2tqsoxj3ste4mqhzmbwhibms7obhqrw62c6vquxdkwrsiez4@yxmexbvocds7>
Date: Mon, 22 Apr 2024 23:02:30 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Sui Jingfeng <sui.jingfeng@...ux.dev>
Cc: Neil Armstrong <neil.armstrong@...aro.org>, 
	Robert Foss <rfoss@...nel.org>, Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
	Andrzej Hajda <andrzej.hajda@...el.com>, Jonas Karlman <jonas@...boo.se>, 
	Jernej Skrabec <jernej.skrabec@...il.com>, Maxime Ripard <mripard@...nel.org>, 
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
	Daniel Vetter <daniel@...ll.ch>, Phong LE <ple@...libre.com>, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 6/9] drm-bridge: sii902x: Use fwnode API to acquire
 device properties

On Tue, Apr 23, 2024 at 03:19:00AM +0800, Sui Jingfeng wrote:
> Make this driver less DT-dependent by calling the freshly created helper
> functions, which reduce boilerplate. Should be no functional changes for
> DT based systems.
> 
> Signed-off-by: Sui Jingfeng <sui.jingfeng@...ux.dev>
> ---
>  drivers/gpu/drm/bridge/sii902x.c | 43 +++++++++++---------------------
>  1 file changed, 14 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/sii902x.c
> index 8f84e98249c7..04436f318c7f 100644
> --- a/drivers/gpu/drm/bridge/sii902x.c
> +++ b/drivers/gpu/drm/bridge/sii902x.c
> @@ -827,20 +827,19 @@ static int sii902x_audio_codec_init(struct sii902x *sii902x,
>  		.spdif = 0,
>  		.max_i2s_channels = 0,
>  	};
> +	struct fwnode_handle *fwnode = dev_fwnode(dev);
>  	u8 lanes[4];
>  	int num_lanes, i;
>  
> -	if (!of_property_read_bool(dev->of_node, "#sound-dai-cells")) {
> +	if (!fwnode_property_present(fwnode, "#sound-dai-cells")) {
>  		dev_dbg(dev, "%s: No \"#sound-dai-cells\", no audio\n",
>  			__func__);
>  		return 0;
>  	}
>  
> -	num_lanes = of_property_read_variable_u8_array(dev->of_node,
> -						       "sil,i2s-data-lanes",
> -						       lanes, 1,
> -						       ARRAY_SIZE(lanes));
> -
> +	num_lanes = fwnode_property_read_u8_array(fwnode,
> +						  "sil,i2s-data-lanes",
> +						  lanes, ARRAY_SIZE(lanes));

You have lost support for having less than 4 lanes. Please see the
documentation for this function.

>  	if (num_lanes == -EINVAL) {
>  		dev_dbg(dev,
>  			"%s: No \"sil,i2s-data-lanes\", use default <0>\n",
> @@ -1097,13 +1096,13 @@ static int sii902x_init(struct sii902x *sii902x)
>  		goto err_unreg_audio;
>  
>  	sii902x->bridge.funcs = &sii902x_bridge_funcs;
> -	sii902x->bridge.of_node = dev->of_node;
>  	sii902x->bridge.timings = &default_sii902x_timings;
>  	sii902x->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID;
>  
>  	if (sii902x->i2c->irq > 0)
>  		sii902x->bridge.ops |= DRM_BRIDGE_OP_HPD;
>  
> +	drm_bridge_set_node(&sii902x->bridge, dev_fwnode(dev));

Move back to the place of the of_node setter.

>  	drm_bridge_add(&sii902x->bridge);
>  
>  	return 0;
> @@ -1118,7 +1117,6 @@ static int sii902x_init(struct sii902x *sii902x)
>  static int sii902x_probe(struct i2c_client *client)
>  {
>  	struct device *dev = &client->dev;
> -	struct device_node *endpoint;
>  	struct sii902x *sii902x;
>  	static const char * const supplies[] = {"iovcc", "cvcc12"};
>  	int ret;
> @@ -1147,27 +1145,14 @@ static int sii902x_probe(struct i2c_client *client)
>  		return PTR_ERR(sii902x->reset_gpio);
>  	}
>  
> -	endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 1, -1);
> -	if (endpoint) {
> -		struct device_node *remote = of_graph_get_remote_port_parent(endpoint);
> -
> -		of_node_put(endpoint);
> -		if (!remote) {
> -			dev_err(dev, "Endpoint in port@1 unconnected\n");
> -			return -ENODEV;
> -		}
> -
> -		if (!of_device_is_available(remote)) {
> -			dev_err(dev, "port@1 remote device is disabled\n");
> -			of_node_put(remote);
> -			return -ENODEV;
> -		}
> -
> -		sii902x->next_bridge = of_drm_find_bridge(remote);
> -		of_node_put(remote);
> -		if (!sii902x->next_bridge)
> -			return dev_err_probe(dev, -EPROBE_DEFER,
> -					     "Failed to find remote bridge\n");
> +	sii902x->next_bridge = drm_bridge_find_next_bridge_by_fwnode(dev_fwnode(dev), 1);
> +	if (!sii902x->next_bridge) {
> +		return dev_err_probe(dev, -EPROBE_DEFER,
> +				     "Failed to find the next bridge\n");
> +	} else if (IS_ERR(sii902x->next_bridge)) {
> +		ret = PTR_ERR(sii902x->next_bridge);
> +		dev_err(dev, "Error on find the next bridge: %d\n", ret);
> +		return ret;
>  	}
>  
>  	mutex_init(&sii902x->mutex);
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry