linux-kernel - Re: [PATCH 1/8] drm/mediatek: Use regmap for register access

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Date:   Thu, 23 Nov 2017 09:54:42 +0100
From:   Philipp Zabel <p.zabel@...gutronix.de>
To:     Matthias Brugger <matthias.bgg@...il.com>,
        ulrich.hecht+renesas@...il.com, laurent.pinchart@...asonboard.com,
        ck.hu@...iatek.com, airlied@...ux.ie, robh+dt@...nel.org,
        mark.rutland@....com, mturquette@...libre.com,
        sboyd@...eaurora.org, lee.jones@...aro.org
Cc:     davem@...emloft.net, gregkh@...uxfoundation.org,
        mchehab@...nel.org, rdunlap@...radead.org,
        pi-cheng.chen@...aro.org, sean.wang@...iatek.com,
        linux-clk@...r.kernel.org, linux@...linux.org.uk,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        Matthias Brugger <mbrugger@...e.com>
Subject: Re: [PATCH 1/8] drm/mediatek: Use regmap for register access

Hi Matthias,

On Tue, 2017-11-14 at 22:41 +0100, Matthias Brugger wrote:
> The mmsys memory space is shared between the drm and the
> clk driver. Use regmap to access it.
> 
> Signed-off-by: Matthias Brugger <mbrugger@...e.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_crtc.c |  4 ++--
>  drivers/gpu/drm/mediatek/mtk_drm_ddp.c  | 30 +++++++++++++++++-------------
>  drivers/gpu/drm/mediatek/mtk_drm_ddp.h  |  4 ++--
>  drivers/gpu/drm/mediatek/mtk_drm_drv.c  | 13 ++++---------
>  drivers/gpu/drm/mediatek/mtk_drm_drv.h  |  2 +-
>  5 files changed, 26 insertions(+), 27 deletions(-)
[...]
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
> index 8130f3dab661..1227d6db07da 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
> @@ -185,16 +185,16 @@ static unsigned int mtk_ddp_sel_in(enum mtk_ddp_comp_id cur,
>  	return value;
>  }
>  
> -static void mtk_ddp_sout_sel(void __iomem *config_regs,
> +static void mtk_ddp_sout_sel(struct regmap *config_regs,
>  			     enum mtk_ddp_comp_id cur,
>  			     enum mtk_ddp_comp_id next)
>  {
>  	if (cur == DDP_COMPONENT_BLS && next == DDP_COMPONENT_DSI0)
> -		writel_relaxed(BLS_TO_DSI_RDMA1_TO_DPI1,
> -			       config_regs + DISP_REG_CONFIG_OUT_SEL);
> +		regmap_write(config_regs, DISP_REG_CONFIG_OUT_SEL,
> +				BLS_TO_DSI_RDMA1_TO_DPI1);
>  }
>  
> -void mtk_ddp_add_comp_to_path(void __iomem *config_regs,
> +void mtk_ddp_add_comp_to_path(struct regmap *config_regs,
>  			      enum mtk_ddp_comp_id cur,
>  			      enum mtk_ddp_comp_id next)
>  {
> @@ -202,20 +202,22 @@ void mtk_ddp_add_comp_to_path(void __iomem *config_regs,
>  
>  	value = mtk_ddp_mout_en(cur, next, &addr);
>  	if (value) {
> -		reg = readl_relaxed(config_regs + addr) | value;
> -		writel_relaxed(reg, config_regs + addr);
> +		regmap_read(config_regs, addr, &reg);
> +		reg |= value;
> +		regmap_write(config_regs, addr, reg);

You can use

		regmap_update_bits(config_regs, addr, value, value);

here and drop the local variable reg.

>  	}
>  
>  	mtk_ddp_sout_sel(config_regs, cur, next);
>  
>  	value = mtk_ddp_sel_in(cur, next, &addr);
>  	if (value) {
> -		reg = readl_relaxed(config_regs + addr) | value;
> -		writel_relaxed(reg, config_regs + addr);
> +		regmap_read(config_regs, addr, &reg);
> +		reg |= value;
> +		regmap_write(config_regs, addr, reg);

		regmap_update_bits(config_regs, addr, value, value);

>  	}
>  }
>  
> -void mtk_ddp_remove_comp_from_path(void __iomem *config_regs,
> +void mtk_ddp_remove_comp_from_path(struct regmap *config_regs,
>  				   enum mtk_ddp_comp_id cur,
>  				   enum mtk_ddp_comp_id next)
>  {
> @@ -223,14 +225,16 @@ void mtk_ddp_remove_comp_from_path(void __iomem *config_regs,
>  
>  	value = mtk_ddp_mout_en(cur, next, &addr);
>  	if (value) {
> -		reg = readl_relaxed(config_regs + addr) & ~value;
> -		writel_relaxed(reg, config_regs + addr);
> +		regmap_read(config_regs, addr, &reg);
> +		reg &= ~value;
> +		regmap_write(config_regs, addr, reg);

		regmap_update_bits(config_regs, addr, value, 0);

>  	}
>  
>  	value = mtk_ddp_sel_in(cur, next, &addr);
>  	if (value) {
> -		reg = readl_relaxed(config_regs + addr) & ~value;
> -		writel_relaxed(reg, config_regs + addr);
> +		regmap_read(config_regs, addr, &reg);
> +		reg &= ~value;
> +		regmap_write(config_regs, addr, reg);

		regmap_update_bits(config_regs, addr, value, 0);

Reviewed-by: Philipp Zabel <p.zabel@...gutronix.de>

regards
Philipp