[RFC][PATCH] drm/bridge: lvds-codec: Add support for pixel data sampling edge select

[Sam Ravnborg]

Hi Marek.

On Sat, Oct 03, 2020 at 01:08:23AM +0200, Marek Vasut wrote:
> The OnSemi FIN3385 Parallel-to-LVDS encoder has a dedicated input line to
> select input pixel data sampling edge. Add DT property "pixelclk-active",
> same as the one used by display timings, and configure bus flags based on
> this DT property.

Why is it that this information cannot come from the panel driver?
The property tell when data are sampled and the FIN3385 Parallel-to-LVDS
is the one that transmit the data - not then one that samples the data.
Correct?

	Sam

> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Alexandre Torgue <alexandre.torgue at st.com>
> Cc: Andrzej Hajda <a.hajda at samsung.com>
> Cc: Antonio Borneo <antonio.borneo at st.com>
> Cc: Benjamin Gaignard <benjamin.gaignard at st.com>
> Cc: Biju Das <biju.das.jz at bp.renesas.com>
> Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Cc: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
> Cc: Philippe Cornu <philippe.cornu at st.com>
> Cc: Sam Ravnborg <sam at ravnborg.org>
> Cc: Vincent Abriou <vincent.abriou at st.com>
> Cc: Yannick Fertre <yannick.fertre at st.com>
> Cc: linux-arm-kernel at lists.infradead.org
> Cc: linux-stm32 at st-md-mailman.stormreply.com
> To: dri-devel at lists.freedesktop.org
> ---
>  drivers/gpu/drm/bridge/lvds-codec.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/lvds-codec.c b/drivers/gpu/drm/bridge/lvds-codec.c
> index f52ccffc1bd1..bc941d4fb5b9 100644
> --- a/drivers/gpu/drm/bridge/lvds-codec.c
> +++ b/drivers/gpu/drm/bridge/lvds-codec.c
> @@ -19,6 +19,7 @@ struct lvds_codec {
>  	struct device *dev;
>  	struct drm_bridge bridge;
>  	struct drm_bridge *panel_bridge;
> +	struct drm_bridge_timings timings;
>  	struct regulator *vcc;
>  	struct gpio_desc *powerdown_gpio;
>  	u32 connector_type;
> @@ -80,6 +81,7 @@ static int lvds_codec_probe(struct platform_device *pdev)
>  	struct device_node *panel_node;
>  	struct drm_panel *panel;
>  	struct lvds_codec *lvds_codec;
> +	u32 val;
>  	int ret;
>  
>  	lvds_codec = devm_kzalloc(dev, sizeof(*lvds_codec), GFP_KERNEL);
> @@ -124,6 +126,12 @@ static int lvds_codec_probe(struct platform_device *pdev)
>  	if (IS_ERR(lvds_codec->panel_bridge))
>  		return PTR_ERR(lvds_codec->panel_bridge);
>  
> +	if (!of_property_read_u32(dev->of_node, "pixelclk-active", &val)) {
> +		lvds_codec->timings.input_bus_flags = val ?
> +			DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE :
> +			DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE;
> +	}
> +
>  	/*
>  	 * The panel_bridge bridge is attached to the panel's of_node,
>  	 * but we need a bridge attached to our of_node for our user
> @@ -131,6 +139,7 @@ static int lvds_codec_probe(struct platform_device *pdev)
>  	 */
>  	lvds_codec->bridge.of_node = dev->of_node;
>  	lvds_codec->bridge.funcs = &funcs;
> +	lvds_codec->bridge.timings = &lvds_codec->timings;
>  	drm_bridge_add(&lvds_codec->bridge);
>  
>  	platform_set_drvdata(pdev, lvds_codec);
> -- 
> 2.28.0
> 
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