Re: [PATCH v2 1/8] mmc: sdhci-pxav2: add initial support for PXA168 V1 controller

[Adrian Hunter <adrian.hunter@intel.com>]

On 26/12/22 22:35, Doug Brown wrote:
> Hi Adrian,
> 
> On 12/22/2022 8:03 AM, Adrian Hunter wrote:
>> On 2/12/22 05:13, Doug Brown wrote:
>>> Add a new compatible string for the version 1 controller used in the
>>> PXA168, along with necessary quirks. Use a separate ops struct in
>>> preparation for a silicon bug workaround only necessary on V1.
>>>
>>> Signed-off-by: Doug Brown <doug@schmorgal.com>
>>> ---
>>>   drivers/mmc/host/sdhci-pxav2.c | 18 +++++++++++++++++-
>>>   1 file changed, 17 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci-pxav2.c b/drivers/mmc/host/sdhci-pxav2.c
>>> index f18906b5575f..2f9fa0ecbddd 100644
>>> --- a/drivers/mmc/host/sdhci-pxav2.c
>>> +++ b/drivers/mmc/host/sdhci-pxav2.c
>>> @@ -101,6 +101,14 @@ static void pxav2_mmc_set_bus_width(struct sdhci_host *host, int width)
>>>       writeb(ctrl, host->ioaddr + SDHCI_HOST_CONTROL);
>>>   }
>>>   +static const struct sdhci_ops pxav1_sdhci_ops = {
>>> +    .set_clock     = sdhci_set_clock,
>>> +    .get_max_clock = sdhci_pltfm_clk_get_max_clock,
>>> +    .set_bus_width = pxav2_mmc_set_bus_width,
>>> +    .reset         = pxav2_reset,
>>> +    .set_uhs_signaling = sdhci_set_uhs_signaling,
>>> +};
>>> +
>>>   static const struct sdhci_ops pxav2_sdhci_ops = {
>>>       .set_clock     = sdhci_set_clock,
>>>       .get_max_clock = sdhci_pltfm_clk_get_max_clock,
>>> @@ -114,6 +122,9 @@ static const struct of_device_id sdhci_pxav2_of_match[] = {
>>>       {
>>>           .compatible = "mrvl,pxav2-mmc",
>>>       },
>>> +    {
>>> +        .compatible = "mrvl,pxav1-mmc",
>>> +    },
>>>       {},
>>>   };
>>>   MODULE_DEVICE_TABLE(of, sdhci_pxav2_of_match);
>>> @@ -208,7 +219,12 @@ static int sdhci_pxav2_probe(struct platform_device *pdev)
>>>               host->mmc->pm_caps |= pdata->pm_caps;
>>>       }
>>>   -    host->ops = &pxav2_sdhci_ops;
>>> +    if (match && of_device_is_compatible(dev->of_node, "mrvl,pxav1-mmc")) {
>>> +        host->quirks |= SDHCI_QUIRK_NO_BUSY_IRQ | SDHCI_QUIRK_32BIT_DMA_SIZE;
>>> +        host->ops = &pxav1_sdhci_ops;
>>> +    } else {
>>> +        host->ops = &pxav2_sdhci_ops;
>>> +    }
>>
>> It would be better to put the information above in a structure and
>> get it with of_device_get_match_data() (instead of of_match_device).
>> Also drivers typically assume there is always a match since that
>> is the only way the driver ->probe() will get run.
> 
> Thanks for all of your great feedback on this series. That makes sense.
> I did have one question about this suggestion. There are other parts of
> sdhci_pxav2_probe() that don't assume there was a match so that it can
> be set up the old way as a platform_device without CONFIG_OF. I was
> trying to preserve compatibility by defaulting to pxav2_sdhci_ops if
> it was set up as a platform_device. Is it all right if I leave a
> fallback in place for that, or should I just end compatibility with the
> old way at this point and assume a match in all cases? I don't see any
> legacy board files that use this driver.

I didn't think about matching by name.  As you say, there doesn't seem
to be anything in mainline.  I will leave it to you to decide.

> 
>>
>>>         ret = sdhci_add_host(host);
>>>       if (ret)
>>
> 
> Thanks,
> Doug