[RFC 12/16] drm/armada: add bus-width property to the output endpoint

[Russell King - ARM Linux]

On Tue, Dec 18, 2018 at 04:37:38PM +0100, Lubomir Rintel wrote:
> This makes it possible to choose a different pixel format for the
> endpoint. Modelled after what other LCD controllers use, including
> marvell,pxa2xx-lcdc and atmel,hlcdc-display-controller and perhaps more.
> 
> Signed-off-by: Lubomir Rintel <lkundrak at v3.sk>
> ---
>  drivers/gpu/drm/armada/armada_crtc.c | 26 +++++++++++++++++++++++++-
>  1 file changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/armada/armada_crtc.c b/drivers/gpu/drm/armada/armada_crtc.c
> index da9360688b55..5400fb925bcd 100644
> --- a/drivers/gpu/drm/armada/armada_crtc.c
> +++ b/drivers/gpu/drm/armada/armada_crtc.c
> @@ -724,6 +724,8 @@ static int armada_drm_crtc_create(struct drm_device *drm, struct device *dev,
>  	struct armada_private *priv = drm->dev_private;
>  	struct armada_crtc *dcrtc;
>  	struct drm_plane *primary;
> +	struct device_node *endpoint;
> +	u32 bus_width = 24;
>  	void __iomem *base;
>  	int ret;
>  
> @@ -744,8 +746,30 @@ static int armada_drm_crtc_create(struct drm_device *drm, struct device *dev,
>  	dcrtc->base = base;
>  	dcrtc->num = drm->mode_config.num_crtc;
>  	dcrtc->clk = ERR_PTR(-EINVAL);
> -	dcrtc->cfg_dumb_ctrl = DUMB24_RGB888_0;
>  	dcrtc->spu_iopad_ctrl = CFG_VSCALE_LN_EN | CFG_IOPAD_DUMB24;
> +
> +	endpoint = of_get_next_child(port, NULL);
> +	of_property_read_u32(endpoint, "bus-width", &bus_width);
> +	of_node_put(endpoint);
> +
> +	switch (bus_width) {
> +	case 12:
> +		dcrtc->cfg_dumb_ctrl = DUMB12_RGB444_0;
> +		break;
> +	case 16:
> +		dcrtc->cfg_dumb_ctrl = DUMB16_RGB565_0;
> +		break;
> +	case 18:
> +		dcrtc->cfg_dumb_ctrl = DUMB18_RGB666_0;
> +		break;
> +	case 24:
> +		dcrtc->cfg_dumb_ctrl = DUMB24_RGB888_0;
> +		break;
> +	default:
> +		DRM_ERROR("unsupported bus width: %d\n", bus_width);
> +		return -EINVAL;
> +	}
> +

This needs to default to 24bpp if the property is not present.

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