linux-kernel - Re: [PATCH 14/18] drm/mediatek: add connect function for ovl

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Date:   Thu, 27 Dec 2018 12:56:13 +0800
From:   CK Hu <ck.hu@...iatek.com>
To:     Yongqiang Niu <yongqiang.niu@...iatek.com>
CC:     Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        <dri-devel@...ts.freedesktop.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>
Subject: Re: [PATCH 14/18] drm/mediatek: add connect function for ovl

Hi, Yongqiang:

On Mon, 2018-12-24 at 16:08 +0800, Yongqiang Niu wrote:
> This patch add connect function for ovl

Could you describe more about how ovl-2l works? I guess that ovl-2l is a
ovl hardware which has 3 layer, the bottom two layer is from DRAM and
the top layer is from another hardware (maybe the ovl). If my guess is
correct, why not just implement this function in mtk_ovl_layer_on()? In
mtk_ovl_layer_on(), you could do as

if (idx == ovl->data->layer_nr) {
	mtk_ddp_write_mask((1 << 2), comp,
			DISP_REG_OVL_DATAPATH_CON, OVL_BGCLR_SEL_IN);

	return;
}

So does mtk_ovl_layer_off().

Regards,
CK

> 
> Signed-off-by: Yongqiang Niu <yongqiang.niu@...iatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> index a0ab760..3b2ce77 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> @@ -27,6 +27,8 @@
>  #define DISP_REG_OVL_EN				0x000c
>  #define DISP_REG_OVL_RST			0x0014
>  #define DISP_REG_OVL_ROI_SIZE			0x0020
> +#define DISP_REG_OVL_DATAPATH_CON		0x0024
> +#define OVL_BGCLR_SEL_IN                        BIT(2)
>  #define DISP_REG_OVL_ROI_BGCLR			0x0028
>  #define DISP_REG_OVL_SRC_CON			0x002c
>  #define DISP_REG_OVL_CON(n)			(0x0030 + 0x20 * (n))
> @@ -245,6 +247,19 @@ static void mtk_ovl_layer_config(struct mtk_ddp_comp *comp, unsigned int idx,
>  		mtk_ovl_layer_on(comp, idx);
>  }
>  
> +static void mtk_ovl_connect(struct mtk_ddp_comp *comp,
> +			    enum mtk_ddp_comp_id prev)
> +{
> +	int is_ovl = 0;
> +
> +	if (prev == DDP_COMPONENT_OVL0 || prev == DDP_COMPONENT_OVL1 ||
> +	    prev == DDP_COMPONENT_OVL0_2L || prev == DDP_COMPONENT_OVL1_2L)
> +		is_ovl = 1;
> +
> +	mtk_ddp_write_mask((is_ovl << 2), comp,
> +			   DISP_REG_OVL_DATAPATH_CON, OVL_BGCLR_SEL_IN);
> +}
> +
>  static const struct mtk_ddp_comp_funcs mtk_disp_ovl_funcs = {
>  	.config = mtk_ovl_config,
>  	.start = mtk_ovl_start,
> @@ -255,6 +270,7 @@ static void mtk_ovl_layer_config(struct mtk_ddp_comp *comp, unsigned int idx,
>  	.layer_on = mtk_ovl_layer_on,
>  	.layer_off = mtk_ovl_layer_off,
>  	.layer_config = mtk_ovl_layer_config,
> +	.connect = mtk_ovl_connect,
>  };
>  
>  static int mtk_disp_ovl_bind(struct device *dev, struct device *master,