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

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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.







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