Part Number: AM5728
Tool/software: Linux
Hi,
I am trying to control GPIO7_1 through /sys/class/gpio/gpio193.
root@am57xx-evm:/sys/class/gpio/gpio193# cat direction
out
root@am57xx-evm:/sys/class/gpio/gpio193# cat value
0
When I use a osciloscope to measure the voltage, it shows that it is 3.3 V even though I set it to 0.
I took additionally steps and replaced the mux mode settings for mux_data.h
I replaced the old entry for MMC3_DAT2 with {MMC3_DAT2, (M14 | PIN_OUTPUT_PULLUP)}. Please see attached mux_data.h file.
Also, within kernel space I set gpio193 (GPIO7_1) to 0:
gpio_request(193, "gpio7_1");
gpio_direction_output(193, 0);
gpio_export(193, true);
See the debug output:
root@am57xx-evm:/sys/class/gpio/gpio193# cat /sys/kernel/debug/gpio
gpiochip0: GPIOs 0-31, parent: platform/4ae10000.gpio, gpio:
gpiochip1: GPIOs 32-63, parent: platform/48055000.gpio, gpio:
gpio-37 ( |enable ) out lo
gpio-40 ( |? ) out lo
gpio-52 ( |Home ) in hi IRQ
gpio-55 ( |Up ) in hi IRQ
gpio-56 ( |Right ) in hi IRQ
gpio-57 ( |Down ) in hi IRQ
gpio-60 ( |Left ) in hi IRQ
gpiochip2: GPIOs 64-95, parent: platform/48057000.gpio, gpio:
gpiochip3: GPIOs 96-127, parent: platform/48059000.gpio, gpio:
gpio-97 ( |sfp0dis ) out lo
gpio-103 ( |sfp1dis ) out lo
gpio-113 ( |phyadd2 ) out lo
gpio-114 ( |phyadd3 ) out lo
gpio-115 ( |phyadd4 ) out lo
gpio-117 ( |vbus ) in lo IRQ
gpiochip4: GPIOs 128-159, parent: platform/4805b000.gpio, gpio:
gpio-136 ( |vmmcwl_fixed ) out lo
gpio-142 ( |phyresetn ) out hi
gpiochip5: GPIOs 160-191, parent: platform/4805d000.gpio, gpio:
gpio-187 ( |cd ) in lo IRQ
gpiochip6: GPIOs 192-223, parent: platform/48051000.gpio, gpio:
gpio-193 ( |gpio7_1 ) out lo
gpio-200 ( |? ) out hi
gpio-201 ( |? ) out lo
gpio-206 ( |? ) out lo
gpio-207 ( |? ) out lo
gpiochip7: GPIOs 224-255, parent: platform/48053000.gpio, gpio:
gpio-224 ( |nMR1553 ) out hi
gpiochip8: GPIOs 504-511, parent: platform/48070000.i2c:tps659038@58:tps659038_gpio, 48070000.i2c:tps659038@58:tps659038_gpio, can sl
eep:
gpio-506 ( |GPIO fan control ) out lo
Please let me know how I can enable control of this gpio pin through userspace.
Thanks,
Eeshan
