Re: [EXT] Re: [PATCH] mmc: sdhci-xenon: add gpio hard reset support

Shawn Lin
2017-08-16T00:32:21Z

Hi

On 2017/8/16 6:40, Zhoujie Wu wrote:
> Hi Shawn,

>> ----------------------------------------------------------------------
>> Hi
>>
>> On 2017/8/15 6:19, Zhoujie Wu wrote:
>>> On some platforms, like armada3700, SD card need to
>>> do hard reset by gpio toggling to make it work properly
>>> after warm reset the board.
>>
>> I don't get this that SD card need to do hard reset...
>>
>> I assume what you talk about is either for eMMC or a power-cycle
>> for SD card.
>
> The subject of the patch confused you. What I want is a power-cycle for
> the SD card. The gpio is used to enable/disable the vdd power supply
> for sd card.
> Actually on a3700, when warm reset the board, their is no power-cycle
> for SD card, which will lead sd card can't response correct ocr and
> never set S18A unless a power-cycle.
> This is the purpose I submit this patch.
>

Well, if that is the case, I suggest you to use regulator-gpio.

i.e:

vcc_sd: regulator {
compatible = "regulator-gpio";
regulator-name = "vcc_sd";
regulator-min-microvolt = <3300000>;
regulator-max-microvolt = <3300000>;

gpios = <&gpio1 23 GPIO_ACTIVE_HIGH>;
enable-active-high;
};

&sdhci {
vmmc-supply = <&vcc_sd>;
}

>>
>>> Add gpio hard reset feature for this purpose.
>>>

>
>
>
>