本文主要是介绍rk3399pro应用层操作gpio，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
base：rk3399pro
source:Rockchip_RK3399Pro_TRM
1.想直接操作系统某个引脚，例如GPIO4_C5
io num = 4*32+5 = 149
操作如下：
用系统提供的GPIO调试接口
root@firefly:/sys/class/gpio# cat /sys/kernel/debug/gpio
GPIOs 0-31, platform/pinctrl, gpio0:gpio-1 ( |? ) out hi gpio-5 ( |bt_default_wake_host) in hi gpio-9 ( |dvdd_1v2 ) out lo gpio-13 ( |vcc_mipi ) out lo GPIOs 32-63, platform/pinctrl, gpio1:gpio-33 ( |vcc3v3_3g ) out hi gpio-45 ( |? ) out lo gpio-46 ( |vsel ) out lo gpio-49 ( |vsel ) out lo GPIOs 64-95, platform/pinctrl, gpio2:gpio-68 ( |ep ) out hi gpio-83 ( |bt_default_rts ) out lo gpio-90 ( |bt_default_wake ) out hi gpio-91 ( |reset ) out hi gpio-92 ( |bt_default_reset ) out hi GPIOs 96-127, platform/pinctrl, gpio3:gpio-111 ( |mdio-reset ) out hi GPIOs 128-159, platform/pinctrl, gpio4:gpio-149 ( |vcc5v0_typec ) out lo gpio-154 ( |vcc5v0_host ) out hi GPIOs 511-511, platform/rk805-pinctrl, rk817-gpio, can sleep:
root@firefly:/sys/class/gpio#
root@firefly:/sys/class/gpio# ll
total 0
drwxr-xr-x 2 root root 0 Feb 19 03:47 ./
drwxr-xr-x 68 root root 0 Feb 19 03:47 ../
--w------- 1 root root 4096 Feb 19 03:47 export
lrwxrwxrwx 1 root root 0 Feb 19 03:47 gpiochip0 -> ../../devices/platform/pinctrl/gpio/gpiochip0/
lrwxrwxrwx 1 root root 0 Feb 19 03:47 gpiochip128 -> ../../devices/platform/pinctrl/gpio/gpiochip128/
lrwxrwxrwx 1 root root 0 Feb 19 03:47 gpiochip32 -> ../../devices/platform/pinctrl/gpio/gpiochip32/
lrwxrwxrwx 1 root root 0 Feb 19 03:47 gpiochip511 -> ../../devices/platform/ff3c0000.i2c/i2c-0/0-0020/rk805-pinctrl/gpio/gpiochip511/
lrwxrwxrwx 1 root root 0 Feb 19 03:47 gpiochip64 -> ../../devices/platform/pinctrl/gpio/gpiochip64/
lrwxrwxrwx 1 root root 0 Feb 19 03:47 gpiochip96 -> ../../devices/platform/pinctrl/gpio/gpiochip96/
--w------- 1 root root 4096 Feb 19 03:47 unexport
root@firefly:/sys/class/gpio# echo 149>export
export后目录没有导出，没办法继续操作；
2.用IO指令，也是系统写好的接口，需要自己查好寄存器地址即可
root@firefly:/sys/class/gpio# io --help
Unknown option: ?
Raw memory i/o utility - $Revision: 1.5 $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 toone access, or whole file length)-r|w Read from or Write to memory (default read)-f <file> File to write on memory read, orto read on memory write<addr> The memory address to access<val> The value to write (implies -w)Examples:io 0x1000 Reads one byte from 0x1000io 0x1000 0x12 Writes 0x12 to location 0x1000io -2 -l 8 0x1000 Reads 8 words from 0x1000io -r -f dmp -l 100 200 Reads 100 bytes from addr 200 to fileio -w -f img 0x10000 Writes the whole of file to memoryNote access size (-1|2|4) does not apply to file based accesses.root@firefly:/sys/class/gpio#
从数据手册中知道GPIO4 base address 是0xff790000
DR寄存器offset 是0x00000000
从数据手册 GPIO4-C5 是bit21位 ，所以设置如下：
root@firefly:/sys/class/gpio# io -4 -r 0xff790000
ff790000: 04000000
root@firefly:/sys/class/gpio# io -4 -w 0xff790000 0x04200000
root@firefly:/sys/class/gpio# io -4 -r 0xff790000
ff790000: 04200000
root@firefly:/sys/class/gpio#
如果设置完后，寄存器值没有改变，查下这个GPIO的clk是否打开：
cat /sys/kernel/debug/clk/clk_summary |grep gpio
如果是0 就打开：
echo 1 > /sys/kernel/debug/clk/pclk_gpio4/clk_enable_count
在从新操作即可。
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