Re: [PATCH v2 11/13] mmc: sdhci-esdhc-imx: Add sdhc support for i.MXRT series

[Giulio Benetti]

Hello Rob, Jesse, All,

> Il giorno 4 nov 2021, alle ore 02:05, Rob Herring <robh@xxxxxxxxxx> ha scritto:
> 
> On Wed, Nov 03, 2021 at 12:30:17AM +0100, Giulio Benetti wrote:
>> Hi Fabio, Jesse, All,
>> 
>>> On 11/3/21 12:25 AM, Jesse Taube wrote:
>>> 
>>> 
>>> On 11/2/21 19:17, Fabio Estevam wrote:
>>>> On Tue, Nov 2, 2021 at 7:57 PM Jesse Taube <mr.bossman075@xxxxxxxxx> wrote:
>>>> 
>>>>>   static struct esdhc_soc_data usdhc_imx8qxp_data = {
>>>>>          .flags = ESDHC_FLAG_USDHC | ESDHC_FLAG_STD_TUNING
>>>>> @@ -357,6 +363,7 @@ static const struct of_device_id imx_esdhc_dt_ids[] = {
>>>>>          { .compatible = "fsl,imx7ulp-usdhc", .data = &usdhc_imx7ulp_data, },
>>>>>          { .compatible = "fsl,imx8qxp-usdhc", .data = &usdhc_imx8qxp_data, },
>>>>>          { .compatible = "fsl,imx8mm-usdhc", .data = &usdhc_imx8mm_data, },
>>>>> +       { .compatible = "fsl,imxrt-usdhc", .data = &usdhc_imxrt_data, },
>>>> 
>>>> I thought Rob suggested to use the SoC name, so this would be:
>>>> 
>>> Uh i think that may have been for the UART.
>>>> { .compatible = "fsl,imxrt1050-usdhc", .data = &usdhc_imxrt1050_data, },
>>>> 
>>>> The same applies to the other bindings in the series.
>>>> 
>>>> This way it would be possible to differentiate between future
>>>> supported i.MX RT devices.
>>>> 
>>> This makes sense will do in V3.
>>> 
>> 
>> If we add every SoC we will end up having a long list for every device
>> driver. At the moment it would be 7 parts:
>> 1) imxrt1020
>> 2) imxrt1024
>> .
>> .
>> .
>> 7) imxrt1170
> 
> You don't need a driver update if you use a fallback. When you add 
> the 2nd chip, if you think it is 'the same', then you do:
> 
> compatible = "fsl,imxrt1024-usdhc", "fsl,imxrt1050-usdhc";
> 
> That requires no driver update until the driver needs to handle some 
> difference. And when there is a difference, you don't need a DT update.

This solution is pretty fine, we’re going with that then, for this and every driver involved.

Thank you for pointing us.

Best regards
Giulio Benetti
Benetti Engineering sas

> 
> You could make "fsl,imxrt-usdhc" the fallback from the start if you are 
> adverse to the first way.
> 
> Rob