Re: [PATCH 21/22] arm64: dts: imx8qxp: Remove i.MX7 compatible from USDHC

[Krzysztof Kozlowski <krzk@xxxxxxxxxx>]

On Mon, Aug 24, 2020 at 10:31:31AM +0000, Bough Chen wrote:
> > -----Original Message-----
> > From: Dong Aisheng [mailto:dongas86@xxxxxxxxx]
> > Sent: 2020年8月24日 17:45
> > To: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> > Cc: Aisheng Dong <aisheng.dong@xxxxxxx>; devicetree@xxxxxxxxxxxxxxx;
> > linux-serial@xxxxxxxxxxxxxxx; Anson Huang <anson.huang@xxxxxxx>;
> > linux-gpio@xxxxxxxxxxxxxxx; Fabio Estevam <festevam@xxxxxxxxx>; Linus
> > Walleij <linus.walleij@xxxxxxxxxx>; linux-pm@xxxxxxxxxxxxxxx;
> > linux-mmc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > linux-pwm@xxxxxxxxxxxxxxx; Bartosz Golaszewski
> > <bgolaszewski@xxxxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>;
> > linux-mtd@xxxxxxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; Pengutronix
> > Kernel Team <kernel@xxxxxxxxxxxxxx>; Thierry Reding
> > <thierry.reding@xxxxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>; Sascha
> > Hauer <s.hauer@xxxxxxxxxxxxxx>; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> > linux-watchdog@xxxxxxxxxxxxxxx; Bough Chen <haibo.chen@xxxxxxx>
> > Subject: Re: [PATCH 21/22] arm64: dts: imx8qxp: Remove i.MX7 compatible
> > from USDHC
> > 
> > On Mon, Aug 24, 2020 at 5:15 PM Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> > wrote:
> > >
> > > On Mon, Aug 24, 2020 at 09:00:19AM +0000, Aisheng Dong wrote:
> > > > > From: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> > > > > Sent: Monday, August 24, 2020 12:16 AM
> > > > >
> > > > > The USDHC on i.MX 8QXP has its own compatible described in
> > > > > bindings and used in the driver (with its own quirks).  Remove
> > > > > additional fsl,imx7d-usdhc compatible to fix dtbs_check warnings like:
> > > > >
> > > > >   arch/arm64/boot/dts/freescale/imx8qxp-ai_ml.dt.yaml:
> > mmc@5b010000:
> > > > >     compatible: ['fsl,imx8qxp-usdhc', 'fsl,imx7d-usdhc'] is too long
> > > > >     From schema:
> > > > > /ocumentation/devicetree/bindings/mmc/fsl-imx-esdhc.yaml
> > > > >
> > > > >   arch/arm64/boot/dts/freescale/imx8qxp-ai_ml.dt.yaml:
> > mmc@5b010000:
> > > > >     compatible: Additional items are not allowed
> > > > > ('fsl,imx7d-usdhc' was
> > > > > unexpected)
> > > > >
> > > > > Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> > > >
> > > > For Patch 19-22, I think we should fix dt binding doc.
> > >
> > > Are you sure that these USDHC controllers are compatible with i.MX 7D?
> > > Could they really run with fsl,imx7d-usdhc compatible?
> > 
> > AFAIK uSDHC on QXP is derived from the former platforms with adding a few
> > more new features. e.g. HS400ES/CMDQ.
> > Let me loop in uSDHC driver owner Haibo Chen to double confirm.
> 
> Yes, usdhc of imx8qxp can work by using the compatible "fsl, imx7d-usdhc", but will not support HS400ES/Command Queue any more. Also imx8qxp support Auto CMD23, but imx7d not.
> And imx8qxp need to re-config the clock rate after system PM, imx7d do not need to do this.

Then we can leave the compatible in DTS and I will correct the device
tree schema.

Best regards,
Krzysztof