Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <02bcd7f8-488a-75ec-badb-e62944c3d4e8@collabora.com>
Date:   Thu, 22 Sep 2022 10:16:33 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.2.0
Subject: Re: [PATCH v7,1/3] soc: mediatek: Add mmsys func to adapt to dpi
 output for MT8186
Content-Language: en-US
To:     xinlei.lee@mediatek.com, matthias.bgg@gmail.com,
        jason-jh.lin@mediatek.com, rex-bc.chen@mediatek.com,
        ck.hu@mediatek.com, p.zabel@pengutronix.de, airlied@linux.ie,
        daniel@ffwll.ch
Cc:     dri-devel@lists.freedesktop.org,
        linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Project_Global_Chrome_Upstream_Group@mediatek.com,
        jitao.shi@mediatek.com
References: <1663831764-18169-1-git-send-email-xinlei.lee@mediatek.com>
 <1663831764-18169-2-git-send-email-xinlei.lee@mediatek.com>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <1663831764-18169-2-git-send-email-xinlei.lee@mediatek.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

Il 22/09/22 09:29, xinlei.lee@mediatek.com ha scritto:
> From: Xinlei Lee <xinlei.lee@mediatek.com>
> 
> The difference between MT8186 and other ICs is that when modifying the
> output format, we need to modify the mmsys_base+0x400 register to take
> effect.
> So when setting the dpi output format, we need to call mmsys_func to set
> it to MT8186 synchronously.
> 
> Co-developed-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> ---
>   drivers/soc/mediatek/mt8186-mmsys.h    |  8 +++++++
>   drivers/soc/mediatek/mtk-mmsys.c       | 32 ++++++++++++++++++++++++++
>   include/linux/soc/mediatek/mtk-mmsys.h |  9 ++++++++
>   3 files changed, 49 insertions(+)
> 
> diff --git a/drivers/soc/mediatek/mt8186-mmsys.h b/drivers/soc/mediatek/mt8186-mmsys.h
> index eb1ad9c37a9c..536005d1cc55 100644
> --- a/drivers/soc/mediatek/mt8186-mmsys.h
> +++ b/drivers/soc/mediatek/mt8186-mmsys.h
> @@ -3,6 +3,14 @@
>   #ifndef __SOC_MEDIATEK_MT8186_MMSYS_H
>   #define __SOC_MEDIATEK_MT8186_MMSYS_H
>   
> +/* Values for DPI configuration in MMSYS address space */
> +#define MT8186_MMSYS_DPI_OUTPUT_FORMAT		0x400
> +#define DPI_FORMAT_MASK					0x3

This is GENMASK(1, 0)

> +#define DPI_RGB888_SDR_CON				0
> +#define DPI_RGB888_DDR_CON				1
> +#define DPI_RGB565_SDR_CON				2
> +#define DPI_RGB565_DDR_CON				3
> +
>   #define MT8186_MMSYS_OVL_CON			0xF04
>   #define MT8186_MMSYS_OVL0_CON_MASK			0x3
>   #define MT8186_MMSYS_OVL0_2L_CON_MASK			0xC
> diff --git a/drivers/soc/mediatek/mtk-mmsys.c b/drivers/soc/mediatek/mtk-mmsys.c
> index 06d8e83a2cb5..0857806206dc 100644
> --- a/drivers/soc/mediatek/mtk-mmsys.c
> +++ b/drivers/soc/mediatek/mtk-mmsys.c
> @@ -227,6 +227,38 @@ void mtk_mmsys_ddp_disconnect(struct device *dev,
>   }
>   EXPORT_SYMBOL_GPL(mtk_mmsys_ddp_disconnect);
>   
> +static void mtk_mmsys_update_bits(struct mtk_mmsys *mmsys, u32 offset, u32 mask, u32 val)
> +{
> +	u32 tmp;
> +
> +	tmp = readl_relaxed(mmsys->regs + offset);
> +	tmp = (tmp & ~mask) | val;
> +	writel_relaxed(tmp, mmsys->regs + offset);
> +}
> +
> +void mtk_mmsys_ddp_dpi_fmt_config(struct device *dev, u32 val)
> +{
> +	switch (val) {

You're not handling the MTK_DPI_RGB888_SDR_CON case.

> +	case MTK_DPI_RGB888_DDR_CON: > +		mtk_mmsys_update_bits(dev_get_drvdata(dev), MT8186_MMSYS_DPI_OUTPUT_FORMAT,

Are there any other (future, past, present) MTK SoCs having a MMSYS
DPI_OUTPUT_FORMAT register?

I don't like seeing this kind of model-agnostic function in a not model-agnostic
driver, especially when this is only because of a register address.
That would change if no other future (or present) MediaTek SoCs have this register.

> +				      DPI_FORMAT_MASK, DPI_RGB888_DDR_CON);
> +		break;
> +	case MTK_DPI_RGB565_SDR_CON:
> +		mtk_mmsys_update_bits(dev_get_drvdata(dev), MT8186_MMSYS_DPI_OUTPUT_FORMAT,
> +				      DPI_FORMAT_MASK, DPI_RGB565_SDR_CON);
> +		break;
> +	case MTK_DPI_RGB565_DDR_CON:
> +		mtk_mmsys_update_bits(dev_get_drvdata(dev), MT8186_MMSYS_DPI_OUTPUT_FORMAT,
> +				      DPI_FORMAT_MASK, DPI_RGB565_DDR_CON);
> +		break;

This goes here...

	case MTK_DPI_RGB888_DDR_CON:
> +	default:
> +		mtk_mmsys_update_bits(dev_get_drvdata(dev), MT8186_MMSYS_DPI_OUTPUT_FORMAT,
> +				      DPI_FORMAT_MASK, DPI_RGB888_DDR_CON);
> +		break;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(mtk_mmsys_ddp_dpi_fmt_config);
> +
>   static int mtk_mmsys_reset_update(struct reset_controller_dev *rcdev, unsigned long id,
>   				  bool assert)
>   {
> diff --git a/include/linux/soc/mediatek/mtk-mmsys.h b/include/linux/soc/mediatek/mtk-mmsys.h
> index 59117d970daf..b85f66db33e1 100644
> --- a/include/linux/soc/mediatek/mtk-mmsys.h
> +++ b/include/linux/soc/mediatek/mtk-mmsys.h
> @@ -9,6 +9,13 @@
>   enum mtk_ddp_comp_id;
>   struct device;
>   
> +enum mtk_dpi_out_format_con {
> +	MTK_DPI_RGB888_SDR_CON,
> +	MTK_DPI_RGB888_DDR_CON,
> +	MTK_DPI_RGB565_SDR_CON,
> +	MTK_DPI_RGB565_DDR_CON
> +};
> +
>   enum mtk_ddp_comp_id {
>   	DDP_COMPONENT_AAL0,
>   	DDP_COMPONENT_AAL1,
> @@ -65,4 +72,6 @@ void mtk_mmsys_ddp_disconnect(struct device *dev,
>   			      enum mtk_ddp_comp_id cur,
>   			      enum mtk_ddp_comp_id next);
>   
> +void mtk_mmsys_ddp_dpi_fmt_config(struct device *dev, u32 val);
> +
>   #endif /* __MTK_MMSYS_H */