linux-kernel - Re: [PATCH v10 18/21] drm/mediatek: Add mt8195 Embedded DisplayPort driver

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Date:   Fri, 10 Jun 2022 10:10:40 +0800
From:   Rex-BC Chen <rex-bc.chen@...iatek.com>
To:     CK Hu <ck.hu@...iatek.com>,
        Guillaume Ranquet <granquet@...libre.com>,
        Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Chunfeng Yun (云春峰) 
        <Chunfeng.Yun@...iatek.com>,
        Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>, "Helge Deller" <deller@....de>,
        Jitao Shi (石记涛) 
        <jitao.shi@...iatek.com>
CC:     Markus Schneider-Pargmann <msp@...libre.com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-phy@...ts.infradead.org" <linux-phy@...ts.infradead.org>,
        "linux-fbdev@...r.kernel.org" <linux-fbdev@...r.kernel.org>
Subject: Re: [PATCH v10 18/21] drm/mediatek: Add mt8195 Embedded DisplayPort
 driver

On Thu, 2022-06-09 at 17:37 +0800, CK Hu wrote:
> Hi, Rex:
> 
> On Mon, 2022-05-23 at 12:47 +0200, Guillaume Ranquet wrote:
> > From: Markus Schneider-Pargmann <msp@...libre.com>
> > 
> > This patch adds a DisplayPort driver for the Mediatek mt8195 SoC.
> > 
> > It supports the mt8195, the embedded DisplayPort units. It offers
> > DisplayPort 1.4 with up to 4 lanes.
> > 
> > The driver creates a child device for the phy. The child device
> > will
> > never exist without the parent being active. As they are sharing a
> > register range, the parent passes a regmap pointer to the child so
> > that
> > both can work with the same register range. The phy driver sets
> > device
> > data that is read by the parent to get the phy device that can be
> > used
> > to control the phy properties.
> > 
> > This driver is based on an initial version by
> > Jason-JH.Lin <jason-jh.lin@...iatek.com>.
> > 
> > Signed-off-by: Markus Schneider-Pargmann <msp@...libre.com>
> > Signed-off-by: Guillaume Ranquet <granquet@...libre.com>
> > ---
> 
> [snip]
> 
> > +
> > +static int mtk_dp_power_disable(struct mtk_dp *mtk_dp)
> > +{
> > +	int ret;
> > +
> > +	ret = mtk_dp_write(mtk_dp, MTK_DP_TOP_PWR_STATE, 0);
> > +
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = mtk_dp_write(mtk_dp, MTK_DP_0034,
> 
> MTK_DP_0034 is defined as:
> 
> +#define MTK_DP_0034		      (BIT(2) | BIT(4) | BIT(5))
> 
> I think this a weird address.
> 
> > +			   DA_CKM_CKTX0_EN_FORCE_EN |
> > DA_CKM_BIAS_LPF_EN_FORCE_VAL |
> > +		     DA_CKM_BIAS_EN_FORCE_VAL |
> > +		     DA_XTP_GLB_LDO_EN_FORCE_VAL |
> > +		     DA_XTP_GLB_AVD10_ON_FORCE_VAL);
> > +
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Disable RX */
> > +	ret = mtk_dp_write(mtk_dp, MTK_DP_1040, 0);
> 
> 
> MTK_DP_1040 is defined as:
> 
> +#define MTK_DP_1040		      (BIT(6) | BIT(12))
> 
> I think this a weird address.
> 
> Regards,
> CK
> 

Hello CK,

I will change them to 0x34 and 0x1040.

BRs,
Rex

> > +
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = mtk_dp_write(mtk_dp, MTK_DP_TOP_MEM_PD,
> > +			   0x550 | BIT(FUSE_SEL_SHIFT) |
> > BIT(MEM_ISO_EN_SHIFT));
> > +
> > +	return ret;
> > +}
> 
>