Subject: Re: Warnings for invalid VDD (sdhci-s3c)
To: Adrian Hunter <adrian.hunter@intel.com>,
        Jisheng Zhang <jszhang@marvell.com>,
        Jaehoon Chung <jh80.chung@samsung.com>
References: <CAJKOXPcGDnPm-Ykh6wHqV1YxfTaov5E8iVqBoBn4OJc7BnhgEQ@mail.gmail.com>
 <20160324155840.50474b98@xhacker> <56F3A0B7.4050509@samsung.com>
 <20160324162449.29c9cf78@xhacker> <56F3A88F.50603@samsung.com>
 <56F3E77D.7030201@intel.com> <56F3E9EB.3090207@intel.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>, ludovic.desroches@atmel.com,
        "Ivan T. Ivanov" <ivan.ivanov@linaro.org>, linux-mmc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org
From: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Message-id: <56F8CA0C.2080908@samsung.com>
Date: Mon, 28 Mar 2016 15:07:08 +0900
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On 24.03.2016 22:21, Adrian Hunter wrote:
> On 24/03/16 15:11, Adrian Hunter wrote:
>> On 24/03/16 10:42, Krzysztof Kozlowski wrote:
>>> On 24.03.2016 17:24, Jisheng Zhang wrote:
>>>> Hi,
>>>>
>>>> On Thu, 24 Mar 2016 17:09:27 +0900 Jaehoon Chung wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> On 03/24/2016 04:58 PM, Jisheng Zhang wrote:
>>>>>> Hi,
>>>>>>
>>>>>> On Thu, 24 Mar 2016 16:28:56 +0900 Krzysztof Kozlowski wrote:
>>>>>>   
>>>>>>> Hi,
>>>>>>>
>>>>>>> After 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD via
>>>>>>> external regulator") On Trats2 board I see warnings for invalid VDD
>>>>>>> value (2.8V):
>>>>>>>
>>>>>>> [    3.119656] ------------[ cut here ]------------
>>>>>>> [    3.119666] WARNING: CPU: 3 PID: 90 at
>>>>>>> ../drivers/mmc/host/sdhci.c:1234 sdhci_do_set_ios+0x4cc/0x5e0
>>>>>>> [    3.119669] mmc0: Invalid vdd 0x10  
>>>>>>
>>>>>> Per my understanding, the wrong vdd indicates a wrong ocr, what's the voltage of
>>>>>> this host's vmmc regulator?  
>>>>>
>>>>> As i know, it's fixed-voltage with gpio on trats2. It's 2.8V.
>>>>> I didn't check this entirely..need to check ocr value.
>>>>>
>>>>
>>>> I may know the reason. the vmmc is 2.8v, then mmc_regulator_get_supply() convert
>>>> the value to a ocr as 0x10. The key here is that the 2.8v is invalid in SDHCI
>>>> case and isn't accepted by current sdhci driver.
>>>
>>> Yeah, I already wrote that. It is the part of the warning and my email.
>>> Our regulator is fixed at 2.8 which is 0x10. :)
>>>
>>>> I dunno the elegant solution to handle this case, let's wait for sdhci maintainers
>>>> idea.
>>>
>>> Hmm...
>>
>> I haven't tested it, but what about this:
> 
> And now with checkpatch complaints fixed:
> 
> From: Adrian Hunter <adrian.hunter@intel.com>
> Date: Thu, 24 Mar 2016 14:29:24 +0200
> Subject: [PATCH V2] mmc: sdhci: Fix regression setting power on Trats2 board
> 
> Several commits relating to setting power have been introducing
> problems by putting driver-specific rules into generic SDHCI code.
> 
> Fix by adding a 'set_power' callback and restoring the default
> behaviour prior to commit 918f4cbd4340 ("mmc: sdhci: restore
> behavior when setting VDD via external regulator").  The desired

s/behavior/behaviour/

> behaviour of that commit is gotten by having sdhci-pxav3 provide
> its own set_power callback.
> 
> Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Fixes: 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD...)
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> Cc: stable@vger.kernel.org # v4.5+
> ---
>  drivers/mmc/host/sdhci-pxav3.c | 17 +++++++++++++++++
>  drivers/mmc/host/sdhci.c       | 38 ++++++++++++++++++++++++++++++--------
>  drivers/mmc/host/sdhci.h       |  4 ++++
>  3 files changed, 51 insertions(+), 8 deletions(-)
>

Works for me (sdhci-s3c, Exynos4412 on Trats2 board):
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>


Best regards,
Krzysztof