linux-kernel - Re: [PATCH 3/4] mmc: sdhci_am654: Disable HS400 for AM62P SR1.0 and SR1.1

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Message-ID: <f5b48a22-b036-4df0-b68d-0606b1bc454d@ti.com>
Date: Thu, 7 Aug 2025 17:14:30 -0500
From: Judith Mendez <jm@...com>
To: Andrew Davis <afd@...com>, Nishanth Menon <nm@...com>,
        Tero Kristo
	<kristo@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski
	<krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Adrian Hunter
	<adrian.hunter@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>
CC: Vignesh Raghavendra <vigneshr@...com>,
        Santosh Shilimkar
	<ssantosh@...nel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-mmc@...r.kernel.org>
Subject: Re: [PATCH 3/4] mmc: sdhci_am654: Disable HS400 for AM62P SR1.0 and
 SR1.1

Hi Andrew,

On 8/7/25 12:28 PM, Andrew Davis wrote:
> On 8/5/25 6:49 PM, Judith Mendez wrote:
>> This adds SDHCI_AM654_QUIRK_DISABLE_HS400 quirk which shall be used
>> to disable HS400 support. AM62P SR1.0 and SR1.1 do not support HS400
>> due to errata i2458 [0] so disable HS400 for these SoC revisions.
>>
>> [0] https://www.ti.com/lit/er/sprz574a/sprz574a.pdf
>> Signed-off-by: Judith Mendez <jm@...com>
>> ---
>>   drivers/mmc/host/sdhci_am654.c | 16 ++++++++++++++++
>>   1 file changed, 16 insertions(+)
>>
>> diff --git a/drivers/mmc/host/sdhci_am654.c 
>> b/drivers/mmc/host/sdhci_am654.c
>> index e4fc345be7e5..b7d2adff3277 100644
>> --- a/drivers/mmc/host/sdhci_am654.c
>> +++ b/drivers/mmc/host/sdhci_am654.c
>> @@ -156,6 +156,7 @@ struct sdhci_am654_data {
>>   #define SDHCI_AM654_QUIRK_FORCE_CDTEST BIT(0)
>>   #define SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA BIT(1)
>> +#define SDHCI_AM654_QUIRK_DISABLE_HS400 BIT(2)
>>   };
>>   struct window {
>> @@ -820,6 +821,9 @@ static int sdhci_am654_init(struct sdhci_host *host)
>>       if (ret)
>>           goto err_cleanup_host;
>> +    if (sdhci_am654->quirks & SDHCI_AM654_QUIRK_DISABLE_HS400)
>> +        host->mmc->caps2 &= ~(MMC_CAP2_HS400 | MMC_CAP2_HS400_ES);
>> +
>>       ret = __sdhci_add_host(host);
>>       if (ret)
>>           goto err_cleanup_host;
>> @@ -883,6 +887,12 @@ static int sdhci_am654_get_of_property(struct 
>> platform_device *pdev,
>>       return 0;
>>   }
>> +static const struct soc_device_attribute sdhci_am654_descope_hs400[] = {
>> +    { .family = "AM62PX", .revision = "SR1.0" },
>> +    { .family = "AM62PX", .revision = "SR1.1" },
>> +    { /* sentinel */ }
>> +};
>> +
>>   static const struct of_device_id sdhci_am654_of_match[] = {
>>       {
>>           .compatible = "ti,am654-sdhci-5.1",
>> @@ -970,6 +980,12 @@ static int sdhci_am654_probe(struct 
>> platform_device *pdev)
>>       if (ret)
>>           return dev_err_probe(dev, ret, "parsing dt failed\n");
>> +    soc = soc_device_match(sdhci_am654_descope_hs400);
>> +    if (soc) {
>> +        dev_err(dev, "Disable descoped HS400 mode for this silicon 
>> revision\n");
> 
> Not really an error, use dev_info() or dev_warn(). Also this message
> should go up in the init function when the caps are actually removed,
> and only printed if the caps were set in the first place.

Will fix for v2, thanks

~ Judith