mmc wp - imx6ul

anantharamachan · ‎09-26-2018

Hi,

I'm using i.MX6UL processor. I want to enable write protection for the usdhc1 [mmc].

But setting the register MX6UL_PAD_CSI_DATA04__USDHC1_WP to proper value. but still seeing write protection is not enabled for the sd card connected.

I even tried adding following line to DTS file:

&usdhc1 {
   pinctrl-names = "default";
   pinctrl-0 = <&pinctrl_usdhc1>;
   cd-gpios = <&gpio2 21 0>;
   wp-gpios = <&gpio4 25 0>;
   no-1-8-v;
   keep-power-in-suspend;
   enable-sdio-wakeup;
   status = "okay";
};

But still it didnt work.

Am I missing any setting further? Can you please help me out.

BR,

Anantha R

igorpadykov · ‎09-26-2018

Hi Anantha

mmc wp-gpios usage is described in linux documentation

linux/Documentation/devicetree/bindings/mmc/mmc.txt

mmc.txt\mmc\bindings\devicetree\Documentation - linux-imx - i.MX Linux kernel

and one can check if valid gpio polarity used in the case.

Best regards
igor
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anantharamachan · ‎09-27-2018

Hi Igor,

Thanks for the response.

Indeed I followed the linux documentation. [As I mentioned in my initial post]. But still I dont see wp enabled when the GPIO is set to high through hardware.

I configured the register MX6UL_PAD_CSI_DATA04__USDHC1_WP

[#define MX6UL_PAD_CSI_DATA04__USDHC1_WP 0x01F4 0x0480 0x0000 8 0] in DTB set to 0x17059.

& modified usdhc1 node as mentioned below.

&usdhc1 {
   pinctrl-names = "default";
   pinctrl-0 = <&pinctrl_usdhc1>;
   cd-gpios = <&gpio2 21 0>;
   wp-gpios = <&gpio4 25 0>;
   no-1-8-v;
   keep-power-in-suspend;
   enable-sdio-wakeup;
   status = "okay";
};

Even polarity is checked - GPIO value toggles when pin input toggles. But WP functionality is not working as expected. [it allows file/folder creation still to the mmc]. Can you please let me know if I miss any further setting?

Thanks in advance for your support.

BR,

Anantha R

igorpadykov · ‎09-27-2018

Hi Anantha

for using gpio4 25 as wp IOMUXC_SW_MUX_CTL_PAD_CSI_DATA04

should be configured as 0101 ALT5 — Select mux mode: ALT5 mux port: GPIO4_IO25 of instance: gpio4

not as 1000 ALT8 — Select mux mode: ALT8 mux port: USDHC1_WP of instance: usdhc1

Best regards
igor