Hello all,
First off, I'm still pretty new to embedded devices and really just working at this level of software, so I'm sorry if anything here seems like a stupid question.
I've got a custom Imx6ul board based on the 9x9 evk (interestingly the u-boot only works if i target it at the 14x14, but that's a topic for another time...).
I have been using gpio pins 0, 1, 2, 3, and 4 for like i normally would in linux using sysfs. This made it a surprise to me when setting gpio 5 did not work like expected.
linux would throw no errors, and doing cat /sys/class/gpio/gpio5/value would even display whatever I set it to; however, testing with a multimeter revealed to me that pin 5 was actually pulling low regardless of what I set it to with sysfs.
From what I've read, I must change the dts/dtsi where it configures the pin's function. In my case, gpio 5 appears to be set to do the voltage select for usdhc 1.
pinctrl_usdhc1: usdhc1grp {
fsl,pins = <
MX6UL_PAD_SD1_CMD__USDHC1_CMD 0x17059
MX6UL_PAD_SD1_CLK__USDHC1_CLK 0x10059
MX6UL_PAD_SD1_DATA0__USDHC1_DATA0 0x17059
MX6UL_PAD_SD1_DATA1__USDHC1_DATA1 0x17059
MX6UL_PAD_SD1_DATA2__USDHC1_DATA2 0x17059
MX6UL_PAD_SD1_DATA3__USDHC1_DATA3 0x17059
MX6UL_PAD_UART1_RTS_B__GPIO1_IO19 0x17059 /* SD1 CD */
MX6UL_PAD_GPIO1_IO05__USDHC1_VSELECT 0x17059 /* SD1 VSELECT */
MX6UL_PAD_GPIO1_IO09__GPIO1_IO09 0x17059 /* SD1 RESET */
>;
};
Here are some things I don't understand :
I'm sure there's more, but that's what i'm confused about right now.
Thanks for any help you can give!
Hi JManta
one can look at gpio tutorial on
Best regards
igor