Hi
In our custom board with IMX8mq, we are using pin SAI1_MCLK or SAI5_MCLK for power enables for a backlight led driver,
I am configuring them as GPIO in u-boot and setting them as high, when the unit boots up , the u-boot set those pin as high, but when kernel boots up it becomes low,
I had removed all SAI1 and SAI5 related configuration (with respect to audio from DT ). still it becomes low while boot up.
I tried toggling the GPIO after boot up, not change ( tried both GPIO sysfs and libgpiod). bot behaves same.
but in the same place if I use PIN SAI3_RXD - i am able to use it as expected and I ma able to toggle it after bootup.
does it means that I cannot use MCLK pin as GPIO ? or is there something I am missing at my end.
Thank you for the help.
Thanks and Regards
Terry
已解决! 转到解答。
HI Aldo,
Thank you for the response, Found the issue , it was HW issue , because of the soldering , tried with a new board, it works as expected. Thank you for the help, highly appreciate it.
Thanks and Regards
Terry
Hi Aldo
I configured the SAI1_MCLK as GPIO in pincntrl_hog, and tried to access the GPIO through sysfs and libgpiod.
pinctrl_hog: hoggrp {
fsl,pins = <
MX8MQ_IOMUXC_SAI1_MCLK_GPIO4_IO20 0x19
MX8MQ_IOMUXC_SAI5_MCLK_GPIO3_IO25 0x19
>;
};
for sysfs : I did a echo of the gpio number (bank-1)*32 + pinnumber to the /sys/class/gpio/export. and then tried setting the value after setting the direction.
with both the MCLK , I am not able to toggle it, but I am able to do the same for SAI3_RXD.(able to toggle).
Thanks and Regards
Terry
HI Aldo,
Thank you for the response, Found the issue , it was HW issue , because of the soldering , tried with a new board, it works as expected. Thank you for the help, highly appreciate it.
Thanks and Regards
Terry