Part Number: AM5718
Hi Support Team,
Our customer has asked us if some GPIOs are not working as expected as shown below,
and could you please tell us the possible causes and how to investigate the causes.
I would appreciate your confirmation and response.
【Problems】
-For some GPIOs, the gpio/value setting and the output voltage do not match.
(The output voltage does not go High even though it is set to High.)
-Some GPIOs can be controlled as expected, and some cannot be controlled.
【Details】
The attached text shows the information in # cat /sys/kernel/debug/gpio.
/mnt/home/program/build_cross # echo 0 > /sys/class/gpio/gpio167/value /mnt/home/program/build_cross # echo 1 > /sys/class/gpio/gpio167/value /mnt/home/program/build_cross # cat /sys/kernel/debug/gpio gpiochip0: GPIOs 0-31, parent: platform/4ae10000.gpio, gpio-0-31: gpio-5 ( |sysfs ) in lo gpio-14 ( |sysfs ) in lo gpio-22 ( |sysfs ) in lo gpio-23 ( |sysfs ) in lo gpio-24 ( |sysfs ) in lo gpio-25 ( |sysfs ) in lo gpiochip1: GPIOs 32-63, parent: platform/48055000.gpio, gpio-32-63: gpio-54 ( |sysfs ) in lo gpiochip2: GPIOs 64-95, parent: platform/48057000.gpio, gpio-64-95: gpio-92 ( |sysfs ) out lo gpio-93 ( |sysfs ) out hi gpiochip3: GPIOs 96-127, parent: platform/48059000.gpio, gpio-96-127: gpio-102 ( |sysfs ) out hi gpio-105 ( |sysfs ) out hi gpio-106 ( |sysfs ) out hi gpio-107 ( |sysfs ) out hi gpio-108 ( |sysfs ) out hi gpiochip4: GPIOs 128-159, parent: platform/4805b000.gpio, gpio-128-159: gpio-146 ( |sysfs ) in hi IRQ gpio-147 ( |sysfs ) out hi gpiochip5: GPIOs 160-191, parent: platform/4805d000.gpio, gpio-160-191: gpio-167 ( |sysfs ) out hi gpio-170 ( |sysfs ) in lo gpio-180 ( |sysfs ) out hi gpio-187 ( |sysfs ) in lo gpio-188 ( |sub-lcd-backlight ) out lo gpio-191 ( |vtt_fixed ) out hi gpiochip6: GPIOs 192-223, parent: platform/48051000.gpio, gpio-192-223: gpio-194 ( |sysfs ) in lo gpio-195 ( |sysfs ) out hi gpio-198 ( |sysfs ) out hi gpio-203 ( |sysfs ) in hi gpio-206 ( |sysfs ) out hi gpio-207 ( |sysfs ) out hi gpio-209 ( |sysfs ) in lo gpio-216 ( |sysfs ) in lo gpio-219 ( |sysfs ) in lo gpiochip7: GPIOs 224-255, parent: platform/48053000.gpio, gpio-224-255: gpiochip9: GPIOs 502-503, parent: platform/50000000.gpmc, omap-gpmc: gpiochip8: GPIOs 504-511, parent: platform/48070000.i2c:tps659038@58:tps659038_gpio, 48070000.i2c:tps659038@58:tps659038_gpio, can sleep: /mnt/home/program/build_cross #
Although we have not confirmed the output of all GPIOs, there are some pins
whose GPIO output does not follow the settings.
At the moment, GPIO7_6 (GPIO198) is set to out hi.
If we measure the output voltage, we can see that it is low.
# echo 1 > /sys/class/gpio/gpio198/value
Even if I do something like this, the output voltage does not change.
To eliminate the influence of peripheral circuits, the series resistor near the GPIO pin is removed,
and the voltage is measured on the GPIO pin side.
GPIO4_9 (GPIO105) and GPIO7_14 (GPIO206) output High as expected.
# echo 0 > /sys/class/gpio/gpio105/value
So, we can confirm that the output switches from High to Low.
【Other Customers' status】
1. The version of the SDK
ti-processor-sdk-linux-am57xx-evm-06.03.00.106
linux 4.19
2．The following register values for each GPIO pin
-GPIO7_6 (T7) gpmc_a3 pin
Table 18-1098. CTRL_CORE_PAD_GPMC_A3
gpmc_a3=00040102
-GPIO4_9 (F5) vin2a_d8 pin
Table 18-1196. CTRL_CORE_PAD_VIN2A_D8
vin2a_d8=0004000e
-GPIO7_14 (A26) spi2_sclk pin
Table 18-1480. CTRL_CORE_PAD_SPI2_SCLK
spi2_sclk=0004000e
3. Register value of GPIO_DATAOUT after executing the following command.
# echo 1 > /sys/class/gpio/gpio198/value
GPIO_DATAOUT: 0x0000C048
If you need other information, please let me know.
Best regards,
Kanae
