linux-kernel - Re: [PATCH 0/2] Enable GPIO and I2C configs for TI's J721e platform

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Message-ID: <142b9d12-ea65-320f-aef9-583389aabb3e@ti.com>
Date:   Thu, 8 Oct 2020 15:10:57 +0530
From:   Faiz Abbas <faiz_abbas@...com>
To:     Tero Kristo <t-kristo@...com>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
CC:     <will@...nel.org>, <catalin.marinas@....com>, <nm@...com>
Subject: Re: [PATCH 0/2] Enable GPIO and I2C configs for TI's J721e platform

Tero,

On 08/10/20 2:49 pm, Tero Kristo wrote:
> On 08/10/2020 11:59, Faiz Abbas wrote:
>> Tero,
>>
>> On 06/10/20 6:40 pm, Tero Kristo wrote:
>>> On 06/10/2020 16:03, Faiz Abbas wrote:
>>>> Hi Tero,
>>>>
>>>> On 06/10/20 5:21 pm, Tero Kristo wrote:
>>>>> On 02/10/2020 19:45, Faiz Abbas wrote:
>>>>>> The following patches enable configs in the arm64 defconfig to support
>>>>>> GPIO and I2C support on TI's J721e platform.
>>>>>>
>>>>>> Faiz Abbas (2):
>>>>>>      arm64: defconfig: Enable OMAP I2C driver
>>>>>>      arm64: defconfig: Enable DAVINCI_GPIO driver
>>>>>>
>>>>>>     arch/arm64/configs/defconfig | 2 ++
>>>>>>     1 file changed, 2 insertions(+)
>>>>>>
>>>>>
>>>>> Why are you enabling these?
>>>>>
>>>>> Are they required for booting the board?
>>>>>
>>>>> If not, they shall not be enabled, as it just clutters the arm64 defconfig unnecessarily.
>>>>>
>>>>
>>>> They are required because the SD card regulators need gpio over i2c expander and also
>>>> soc gpio support to come up in UHS modes.
>>>
>>> Is that needed for boot support? If it is only needed with UHS cards, that does not seem important enough for me. We can already boot the board via other means.
>>
>> Without these configs, the regulator drivers keep EPROBE_DEFERing waiting for their gpio drivers
>> to probe and SD card never comes up. This configuration happens before any UHS capabilities are detected.
>>
>> [    1.326654] sdhci-am654 4fb0000.sdhci: _devm_regulator_get id:vmmc ret:-517
>> [    1.333651] sdhci-am654 4fb0000.sdhci: _devm_regulator_get id:vqmmc ret:-517
>> [    1.340693] sdhci-am654 4fb0000.sdhci: sdhci_am654_probe ret:-517
>> [    1.489088] sdhci-am654 4fb0000.sdhci: _devm_regulator_get id:vmmc ret:-517
>> [    1.496067] sdhci-am654 4fb0000.sdhci: _devm_regulator_get id:vqmmc ret:-517
>> [    1.510392] sdhci-am654 4fb0000.sdhci: sdhci_am654_probe ret:-517
>> [    1.543210] sdhci-am654 4fb0000.sdhci: _devm_regulator_get id:vmmc ret:-517
>> [    1.550186] sdhci-am654 4fb0000.sdhci: _devm_regulator_get id:vqmmc ret:-517
>> [    1.568134] sdhci-am654 4fb0000.sdhci: sdhci_am654_probe ret:-517
> 
> This happens because you have merged/enabled UHS support or? This sounds like a regression as I haven't seen this happen before.
> 

Thats right. The EPROBE_DEFERs will happen if my patches enabling UHS modes here are merged. I need to repost them for v5.11-rc1:
https://lore.kernel.org/linux-arm-kernel/20201001190541.6364-1-faiz_abbas@ti.com/

Thanks,
Faiz