Hi I ask access a GPIO port on my imx28 platform board.
At first I say thanks to the answer (https://community.freescale.com/message/365311#365311) to Yuri.
According to Yuri's guide I check the /sys/class/gpio as below.
root@freescale /sys/class/gpio$ ls -l
-rwxrwxrwx 1 root root 4096 Jan 1 20:54 export
lrwxrwxrwx 1 root root 0 Jan 1 19:40 gpiochip0 -> ../../devices/virtual/gpio/gpiochip0
lrwxrwxrwx 1 root root 0 Jan 1 19:40 gpiochip128 -> ../../devices/virtual/gpio/gpiochip128
lrwxrwxrwx 1 root root 0 Jan 1 19:40 gpiochip32 -> ../../devices/virtual/gpio/gpiochip32
lrwxrwxrwx 1 root root 0 Jan 1 19:40 gpiochip64 -> ../../devices/virtual/gpio/gpiochip64
lrwxrwxrwx 1 root root 0 Jan 1 19:40 gpiochip96 -> ../../devices/virtual/gpio/gpiochip96
--w------- 1 root root 4096 Jan 1 19:40 unexport
As you can see after configuration (CONFIG_GPIO_SYSFS) and re-build uImage I see the gpio sysfs.
TRe: how to access GPIO on imx28)
But I can't access the GPIO pin after update uImage.
root@freescale /sys/class/gpio$ echo 36 > /sys/class/gpio/export
root@freescale /sys/class/gpio$ ls -l
-rwxrwxrwx 1 root root 4096 Jan 2 00:00 export
lrwxrwxrwx 1 root root 0 Jan 1 19:40 gpiochip0 -> ../../devices/virtual/gpio/gpiochip0
lrwxrwxrwx 1 root root 0 Jan 1 19:40 gpiochip128 -> ../../devices/virtual/gpio/gpiochip128
lrwxrwxrwx 1 root root 0 Jan 1 19:40 gpiochip32 -> ../../devices/virtual/gpio/gpiochip32
lrwxrwxrwx 1 root root 0 Jan 1 19:40 gpiochip64 -> ../../devices/virtual/gpio/gpiochip64
lrwxrwxrwx 1 root root 0 Jan 1 19:40 gpiochip96 -> ../../devices/virtual/gpio/gpiochip96
--w------- 1 root root 4096 Jan 1 19:40 unexport
36 is pin of SSP0_DATA4 and is BANK2_PIN04. After export could not see the gpio.
I did modify mx28evk_fixed_pins the MUX pin of mx28evk_pins.c file in LINUX/arch/arm/march-mx28.
解決済! 解決策の投稿を見る。
I did it and refer my other answer (Re: how to access GPIO on imx28).
Other answer is some different in my case. I hope my answer help to you.
Thanks.
I did it and refer my other answer (Re: how to access GPIO on imx28).
Other answer is some different in my case. I hope my answer help to you.
Thanks.
The modifing is in mx28evk_fixed_pins is
{
.name = "SSP0_DATA4",
.id = PINID_SSP0_DATA4,
.fun = PIN_GPIO,
.strength = PAD_4MA,
.voltage = PAD_3_3V,
.pullup = 1,
.drive = 1,
.pull = 1,
.data = 1,
.output = 1,
},
I can' understand why I can't access the pin.
Anybody can answer that.
Thanks.