linux-kernel - Re: [PATCH v3 2/2] drm/bridge: sii902x: Set input bus format based on bus-width

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Message-ID: <56b66841-e60b-4dd7-8b96-cf67628fc0e6@linaro.org>
Date: Mon, 21 Oct 2024 14:28:34 +0200
From: neil.armstrong@...aro.org
To: Wadim Egorov <w.egorov@...tec.de>, andrzej.hajda@...el.com,
 rfoss@...nel.org
Cc: Laurent.pinchart@...asonboard.com, jonas@...boo.se,
 jernej.skrabec@...il.com, maarten.lankhorst@...ux.intel.com,
 mripard@...nel.org, tzimmermann@...e.de, airlied@...il.com, simona@...ll.ch,
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 devicetree@...r.kernel.org, bbrezillon@...nel.org, conor+dt@...nel.org,
 krzk+dt@...nel.org, robh@...nel.org, upstream@...ts.phytec.de
Subject: Re: [PATCH v3 2/2] drm/bridge: sii902x: Set input bus format based on
 bus-width

On 17/10/2024 10:55, Wadim Egorov wrote:
> Introduce a bus-width property to define the number of parallel RGB
> input pins connected to the transmitter. The input bus formats are updated
> accordingly. If the property is not specified, default to 24-bit bus-width.
> 
> Signed-off-by: Wadim Egorov <w.egorov@...tec.de>
> ---
> v3: Ensure bus_width is set/defaults to 24 even if an endpoint is not defined
> ---
>   drivers/gpu/drm/bridge/sii902x.c | 24 +++++++++++++++++++++++-
>   1 file changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/sii902x.c
> index 7f91b0db161e..9be9cc5b9025 100644
> --- a/drivers/gpu/drm/bridge/sii902x.c
> +++ b/drivers/gpu/drm/bridge/sii902x.c
> @@ -180,6 +180,8 @@ struct sii902x {
>   	struct gpio_desc *reset_gpio;
>   	struct i2c_mux_core *i2cmux;
>   	bool sink_is_hdmi;
> +	u32 bus_width;
> +
>   	/*
>   	 * Mutex protects audio and video functions from interfering
>   	 * each other, by keeping their i2c command sequences atomic.
> @@ -477,6 +479,8 @@ static u32 *sii902x_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
>   						     u32 output_fmt,
>   						     unsigned int *num_input_fmts)
>   {
> +
> +	struct sii902x *sii902x = bridge_to_sii902x(bridge);
>   	u32 *input_fmts;
>   
>   	*num_input_fmts = 0;
> @@ -485,7 +489,20 @@ static u32 *sii902x_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
>   	if (!input_fmts)
>   		return NULL;
>   
> -	input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> +	switch (sii902x->bus_width) {
> +	case 16:
> +		input_fmts[0] = MEDIA_BUS_FMT_RGB565_1X16;
> +		break;
> +	case 18:
> +		input_fmts[0] = MEDIA_BUS_FMT_RGB666_1X18;
> +		break;
> +	case 24:
> +		input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> +		break;
> +	default:
> +		return NULL;
> +	}
> +
>   	*num_input_fmts = 1;
>   
>   	return input_fmts;
> @@ -1167,6 +1184,11 @@ static int sii902x_probe(struct i2c_client *client)
>   		return PTR_ERR(sii902x->reset_gpio);
>   	}
>   
> +	sii902x->bus_width = 24;
> +	endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
> +	if (endpoint)
> +		of_property_read_u32(endpoint, "bus-width", &sii902x->bus_width);
> +
>   	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);

Reviewed-by: Neil Armstrong <neil.armstrong@...aro.org>