linux-kernel - Re: [PATCH] sdhci: Fix SD card detection issue

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Date: Mon, 15 Apr 2024 12:35:14 +0300
From: Adrian Hunter <adrian.hunter@...el.com>
To: richard clark <richard.xnu.clark@...il.com>,
 Thierry Reding <thierry.reding@...il.com>, Jon Hunter <jonathanh@...dia.com>
Cc: ulf.hansson@...aro.org, linux-mmc@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] sdhci: Fix SD card detection issue

+Nvidia guys

On 15/04/24 11:11, richard clark wrote:
> On Mon, Apr 15, 2024 at 3:18 PM Adrian Hunter <adrian.hunter@...el.com> wrote:
>>
>> On 15/04/24 10:06, Richard Clark wrote:
>>> The mmc_gpio_get_cd(...) will return 0 called from sdhci_get_cd(...), which means
>>> the card is not present. Actually, the card detection pin is active low by default
>>> according to the SDHCI psec, thus the card detection result is not correct, more
>>
>> SDHCI spec covers the SDHCI lines.  GPIO is separate.
>>
>>> specificly below if condition is true in mmc_rescan(...):
>>>       ...
>>>       if (mmc_card_is_removable(host) && host->ops->get_cd &&
>>>               host->ops->get_cd(host) == 0) {
>>>               ...
>>>               goto out;
>>>       }
>>> The SD card device will have no chance to be created.
>>>
>>> This commit fixes this detection issue via the MMC_CAP2_CD_ACTIVE_HIGH cap2 flag,
>>> parsed from the 'cd-inverted' property of DT.
>>
>> What hardware / driver is it?
> sdhci-tegra on Orin.
>>>
>>> Signed-off-by: Richard Clark <richard.xnu.clark@...il.com>
>>> ---
>>>  drivers/mmc/host/sdhci.c | 3 +++
>>>  1 file changed, 3 insertions(+)
>>>
>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> index c79f73459915..79f33a161ca8 100644
>>> --- a/drivers/mmc/host/sdhci.c
>>> +++ b/drivers/mmc/host/sdhci.c
>>> @@ -2483,6 +2483,9 @@ static int sdhci_get_cd(struct mmc_host *mmc)
>>>        * Try slot gpio detect, if defined it take precedence
>>>        * over build in controller functionality
>>>        */
>>> +     if (!(mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH))
>>> +             gpio_cd = !gpio_cd;
>>
>> MMC_CAP2_CD_ACTIVE_HIGH is already handled in
>> mmc_gpiod_request_cd(), and this turns an error (gpio_cd < 0)
>> into 0, which is not right.
> 
> But in case of 'cd-inverted' is not specified, the gpio CD pin return
> 0 which will be explained as card is not present.
>>
>>> +
>>>       if (gpio_cd >= 0)
>>>               return !!gpio_cd;
>>>
>>