Re: [PATCH 2/2] ARM: tegra: roth: enable input on mmc clock pins
From: Stephen Warren
Date: Tue Jun 24 2014 - 11:53:57 EST
On 06/23/2014 11:44 PM, Alexandre Courbot wrote:
> On 06/24/2014 04:01 AM, Stephen Warren wrote:
>> On 06/23/2014 01:32 AM, Alexandre Courbot wrote:
>>> Input had been disabled by mistake on these pins, leading to issues with
>>> SDIO devices like the Wifi module not being probed or random errors
>>> occuring on the SD card.
>>
>> I thought the host controller always drove the clock, so there should be
>> no need for the pin's input path to be enabled. Perhaps it depends on
>> the transfer mode (e.g. UHS)?
>
> That's what I thought too, so I went against what was done downstream
> and disabled input mode. Eventually noticed various issues with MMC
> devices, reverted to the downstream settings and noticed my problems
> were solved by this single change.
Hmm. That's odd. Can you talk to one of the HW engineers behind the
SDHCI controller and get a definitive answer. Thanks.
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