1. GPIO 使用
2. Kernel 开发-GPIO 配置与使用

* number = group * 8 + X = 3 * 8 + 5 = 29
* pin = bank*32 + number= 4 * 32 + 29 = 157

LED1 @ pin 16 :
echo 16 > /sys/class/gpio/export            # 申请 GPIO
cat /sys/class/gpio/gpio16/direction        # 查看默认引脚方向
echo out > /sys/class/gpio/gpio16/direction # 配置成输出方向
echo 1 > /sys/class/gpio/gpio16/value       # 输出高电平为点亮LED
echo 0 > /sys/class/gpio/gpio16/value       # 输出低电平为熄灭 LED

LED2 @ pin 20 :
echo 20 > /sys/class/gpio/export            # 申请 GPIO
cat /sys/class/gpio/gpio20/direction        # 查看默认引脚方向
echo out > /sys/class/gpio/gpio20/direction # 配置成输出方向
echo 1 > /sys/class/gpio/gpio20/value       # 输出高电平为熄灭LED
echo 0 > /sys/class/gpio/gpio20/value       # 输出低电平为点亮 LED

-

* number = group * 8 + X = 3 * 8 + 5 = 29
* pin = bank*32 + number= 4 * 32 + 29 = 157

echo 115 > /sys/class/gpio/export
echo 116 > /sys/class/gpio/export
echo 154 > /sys/class/gpio/export
echo 114 > /sys/class/gpio/export
echo 109 > /sys/class/gpio/export
  
echo in > /sys/class/gpio/gpio109/direction
echo in > /sys/class/gpio/gpio114/direction
echo in > /sys/class/gpio/gpio115/direction
echo in > /sys/class/gpio/gpio116/direction
echo in > /sys/class/gpio/gpio154/direction
  
cat /sys/class/gpio/gpio109/value            # 读KEY状态， 0 按下 1 释放
cat /sys/class/gpio/gpio114/value
cat /sys/class/gpio/gpio115/value
cat /sys/class/gpio/gpio116/value
cat /sys/class/gpio/gpio154/value

#!/bin/bash
pins=(115 116 154 114 109)

for pin in ${pins[@]}; do
    echo ${pin} > /sys/class/gpio/export
    echo in > /sys/class/gpio/gpio${pin}/direction
    echo falling > /sys/class/gpio/gpio${pin}/edge
done

# Pullup
# GPIO3_C2 GPIO3_C3 GPIO3_C4
io -4 -w 0xfdc600a8 0x03F00150
# GPIO3_D2
io -4 -w 0xfdc600bc 0x00300010
# GPIO3_B5
io -4 -w 0xfdc600a4 0x0c000400

io -v -1|2|4 -r|w [-l <len>] [-f <file>] <addr> [<value>]

    -v         Verbose, asks for confirmation
    -1|2|4     Sets memory access size in bytes (default byte)
    -l <len>   Length in bytes of area to access (defaults to
               one access, or whole file length)
    -r|w       Read from or Write to memory (default read)
    -f <file>  File to write on memory read, or
               to read on memory write
    <addr>     The memory address to access
    <val>      The value to write (implies -w)

Examples:
    io 0x1000                  Reads one byte from 0x1000
    io 0x1000 0x12             Writes 0x12 to location 0x1000
    io -2 -l 8 0x1000          Reads 8 words from 0x1000
    io -r -f dmp -l 100 200    Reads 100 bytes from addr 200 to file
    io -w -f img 0x10000       Writes the whole of file to memory

Note access size (-1|2|4) does not apply to file based accesses.

# Read 4 bytes (32bits)
io -4 -r 0xfdcb0010
# Write 4 bytes (32bits)
io -4 -w 0xfdcb0010 0xffff0055

RK3568的寄存器可以通过芯片的TRM手册进行查询。

寄存器的地址是由 Operational Base + offset组成

寄存器的基地址在TRM的Address Mapping章节中描述（《RKRK3568 TRM-Part1》 p.11）

# Check pin function
io -4 0xfdc20010
io -4 0xfdc20014

# Set pin function: GPIO
io -4 -w 0xfdc20010 0x00070000
io -4 -w 0xfdc20014 0x00070000

# Check pin function
io -4 0xfdc60050
io -4 0xfdc60054

io -4 0xfdc60078

io -4 0xfdc6004C

# Set pin function: GPIO
# GPIO3_C2 GPIO3_C3
io -4 -w 0xfdc60050 0x77000000
# GPIO3_C4
io -4 -w 0xfdc20054 0x00070000
# GPIO4_D2
io -4 -w 0xfdc20078 0x07000000
# GPIO3_B5
io -4 -w 0xfdc2004C 0x00700000

# Pullup
# GPIO3_C2 GPIO3_C3 GPIO3_C4
io -4 -w 0xfdc600a8 0x03F00150
# GPIO3_D2
io -4 -w 0xfdc600bc 0x00300010
# GPIO3_B5
io -4 -w 0xfdc600a4 0x0c000400

测试GPIO指令与寄存器操作

使用IO：GPIO0_C4
序号: 20 GPIO3基地址：0xFDD60000 GPIO(0)_SWPORT_DR_H： 0xFDD60004 GPIO(0)_SWPORT_DDR_H: 0xFDD6000C

cd /sys/class/gpio
echo 20 > export
cd gpio20

# Write sysfs and check registers
cat direction    # output: in
io -4 0xFDD6000C # output : fdd6000c:  00007001
                   bit5:0, input
                     
echo out > direction
io -4 0xFDD6000C # output : fdd6000c:  00007011
                   bit5:1, output

cat value        # output: 0
io -4 0xFDD60004 # output : fdd60004:  00007000
                   bit5:0
echo 1 > value
io -4 0xFDD60004 # output : fdd60004:  00007010
                   bit5:1

# Write register and check sysfs
io -4 -w 0xFDD60004 0x00100000
cat value        # output: 0

io -4 -w 0xFDD60004 0x00100010
cat value        # output: 1
                     

# 查看GPIO信息
cat /sys/kernel/debug/gpio

# 查看pin状态
cat /sys/kernel/debug/pinctrl/pinctrl-rockchip-pinctrl/pinconf-pins