linux-kernel - Re: [PATCH v11 06/16] drm/mediatek: gamma: Use bitfield macros

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Message-ID: <3399bf15a6e3d3d4ed5228c858b06c7b28b40aea.camel@mediatek.com>
Date:   Fri, 13 Oct 2023 04:00:54 +0000
From:   CK Hu (胡俊光) <ck.hu@...iatek.com>
To:     "angelogioacchino.delregno@...labora.com" 
        <angelogioacchino.delregno@...labora.com>,
        "chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "wenst@...omium.org" <wenst@...omium.org>,
        Jason-JH Lin (林睿祥) 
        <Jason-JH.Lin@...iatek.com>,
        "kernel@...labora.com" <kernel@...labora.com>,
        "daniel@...ll.ch" <daniel@...ll.ch>,
        "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "amergnat@...libre.com" <amergnat@...libre.com>,
        "airlied@...il.com" <airlied@...il.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "ehristev@...labora.com" <ehristev@...labora.com>,
        "nfraprado@...labora.com" <nfraprado@...labora.com>
Subject: Re: [PATCH v11 06/16] drm/mediatek: gamma: Use bitfield macros

Hi, Angelo:

On Thu, 2023-10-12 at 11:57 +0200, AngeloGioacchino Del Regno wrote:
> Make the code more robust and improve readability by using bitfield
> macros instead of open coding bit operations.
> While at it, also add a definition for LUT_BITS_DEFAULT.

When I apply, I would remove the description of LUT_BITS_DEFAULT.

Reviewed-by: CK Hu <ck.hu@...iatek.com>

> 
> Reviewed-by: Jason-JH.Lin <jason-jh.lin@...iatek.com>
> Reviewed-by: Alexandre Mergnat <amergnat@...libre.com>
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@...labora.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_disp_gamma.c | 28 +++++++++++++++----
> ----
>  1 file changed, 19 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> index d35eaf6dbc2d..81c04518a5eb 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> @@ -3,6 +3,7 @@
>   * Copyright (c) 2021 MediaTek Inc.
>   */
>  
> +#include <linux/bitfield.h>
>  #include <linux/clk.h>
>  #include <linux/component.h>
>  #include <linux/module.h>
> @@ -21,8 +22,14 @@
>  #define GAMMA_LUT_EN					BIT(1)
>  #define GAMMA_DITHERING					BIT(2)
>  #define DISP_GAMMA_SIZE				0x0030
> +#define DISP_GAMMA_SIZE_HSIZE				GENMASK
> (28, 16)
> +#define DISP_GAMMA_SIZE_VSIZE				GENMASK
> (12, 0)
>  #define DISP_GAMMA_LUT				0x0700
>  
> +#define DISP_GAMMA_LUT_10BIT_R			GENMASK(29, 20)
> +#define DISP_GAMMA_LUT_10BIT_G			GENMASK(19, 10)
> +#define DISP_GAMMA_LUT_10BIT_B			GENMASK(9, 0)
> +
>  struct mtk_disp_gamma_data {
>  	bool has_dither;
>  	bool lut_diff;
> @@ -97,9 +104,9 @@ void mtk_gamma_set_common(struct device *dev, void
> __iomem *regs, struct drm_crt
>  		hwlut.blue = drm_color_lut_extract(lut[i].blue, 10);
>  
>  		if (!lut_diff || (i % 2 == 0)) {
> -			word = hwlut.red << 20 +
> -			       hwlut.green << 10 +
> -			       hwlut.red;
> +			word = FIELD_PREP(DISP_GAMMA_LUT_10BIT_R,
> hwlut.red);
> +			word |= FIELD_PREP(DISP_GAMMA_LUT_10BIT_G,
> hwlut.green);
> +			word |= FIELD_PREP(DISP_GAMMA_LUT_10BIT_B,
> hwlut.blue);
>  		} else {
>  			diff.red = lut[i].red - lut[i - 1].red;
>  			diff.red = drm_color_lut_extract(diff.red, 10);
> @@ -110,9 +117,9 @@ void mtk_gamma_set_common(struct device *dev,
> void __iomem *regs, struct drm_crt
>  			diff.blue = lut[i].blue - lut[i - 1].blue;
>  			diff.blue = drm_color_lut_extract(diff.blue,
> 10);
>  
> -			word = diff.blue << 20 +
> -			       diff.green << 10 +
> -			       diff.red;
> +			word = FIELD_PREP(DISP_GAMMA_LUT_10BIT_R,
> diff.red);
> +			word |= FIELD_PREP(DISP_GAMMA_LUT_10BIT_G,
> diff.green);
> +			word |= FIELD_PREP(DISP_GAMMA_LUT_10BIT_B,
> diff.blue);
>  		}
>  		writel(word, (lut_base + i * 4));
>  	}
> @@ -120,7 +127,7 @@ void mtk_gamma_set_common(struct device *dev,
> void __iomem *regs, struct drm_crt
>  	cfg_val = readl(regs + DISP_GAMMA_CFG);
>  
>  	/* Enable the gamma table */
> -	cfg_val |= GAMMA_LUT_EN;
> +	cfg_val |= FIELD_PREP(GAMMA_LUT_EN, 1);
>  
>  	writel(cfg_val, regs + DISP_GAMMA_CFG);
>  }
> @@ -137,9 +144,12 @@ void mtk_gamma_config(struct device *dev,
> unsigned int w,
>  		      unsigned int bpc, struct cmdq_pkt *cmdq_pkt)
>  {
>  	struct mtk_disp_gamma *gamma = dev_get_drvdata(dev);
> +	u32 sz;
> +
> +	sz = FIELD_PREP(DISP_GAMMA_SIZE_HSIZE, w);
> +	sz |= FIELD_PREP(DISP_GAMMA_SIZE_VSIZE, h);
>  
> -	mtk_ddp_write(cmdq_pkt, h << 16 | w, &gamma->cmdq_reg, gamma-
> >regs,
> -		      DISP_GAMMA_SIZE);
> +	mtk_ddp_write(cmdq_pkt, sz, &gamma->cmdq_reg, gamma->regs,
> DISP_GAMMA_SIZE);
>  	if (gamma->data && gamma->data->has_dither)
>  		mtk_dither_set_common(gamma->regs, &gamma->cmdq_reg,
> bpc,
>  				      DISP_GAMMA_CFG, GAMMA_DITHERING,
> cmdq_pkt);