GPIO连接使用说明

这篇文档介绍如何在Android下访问GPIO。

准备工作

固件版本必须满足以下条件：

  • Android M >= V170603
  • Android N >= V170421

如何获取GPIO数值

你可以通过GPIO banks和pins来获取。不同版本的内核数值不同。

Linux 4.9 (Android O )
  • aobus-banks

Banks:

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2
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root@Khadas:/home/khadas# cat /sys/kernel/debug/pinctrl/pinctrl@ff800014/gpio-ranges
GPIO ranges handled:
0: aobus-banks GPIOS [496 - 511] PINS [0 - 15]

Pins:

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root@Khadas:/home/khadas# cat /sys/kernel/debug/pinctrl/pinctrl@ff800014/pins
registered pins: 16
pin 0 (GPIOAO_0)  pinctrl@ff800014
pin 1 (GPIOAO_1)  pinctrl@ff800014
pin 2 (GPIOAO_2)  pinctrl@ff800014
pin 3 (GPIOAO_3)  pinctrl@ff800014
pin 4 (GPIOAO_4)  pinctrl@ff800014
pin 5 (GPIOAO_5)  pinctrl@ff800014
pin 6 (GPIOAO_6)  pinctrl@ff800014
pin 7 (GPIOAO_7)  pinctrl@ff800014
pin 8 (GPIOAO_8)  pinctrl@ff800014
pin 9 (GPIOAO_9)  pinctrl@ff800014
pin 10 (GPIOAO_10)  pinctrl@ff800014
pin 11 (GPIOAO_11)  pinctrl@ff800014
pin 12 (GPIOE_0)  pinctrl@ff800014
pin 13 (GPIOE_1)  pinctrl@ff800014
pin 14 (GPIOE_2)  pinctrl@ff800014
pin 15 (GPIO_TEST_N)  pinctrl@ff800014

例如：获取GPIOAO_6的数值：
Number(GPIOAO_6) = bank + pin = 496 + 6 = 502

  • periphs-banks

Banks:

1
2
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root@Khadas:/home/khadas# cat /sys/kernel/debug/pinctrl/pinctrl@ff634480/gpio-ranges
GPIO ranges handled:
0: periphs-banks GPIOS [410 - 495] PINS [0 - 85]

Pins:

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root@Khadas:/home/khadas# cat /sys/kernel/debug/pinctrl/pinctrl@ff634480/pins
registered pins: 86
pin 0 (GPIOV_0)  pinctrl@ff634480
pin 1 (GPIOZ_0)  pinctrl@ff634480
pin 2 (GPIOZ_1)  pinctrl@ff634480
pin 3 (GPIOZ_2)  pinctrl@ff634480
pin 4 (GPIOZ_3)  pinctrl@ff634480
pin 5 (GPIOZ_4)  pinctrl@ff634480
...
pin 17 (GPIOH_0)  pinctrl@ff634480
pin 18 (GPIOH_1)  pinctrl@ff634480
pin 19 (GPIOH_2)  pinctrl@ff634480
pin 20 (GPIOH_3)  pinctrl@ff634480
pin 21 (GPIOH_4)  pinctrl@ff634480
pin 22 (GPIOH_5)  pinctrl@ff634480
pin 23 (GPIOH_6)  pinctrl@ff634480
pin 24 (GPIOH_7)  pinctrl@ff634480
...
pin 80 (GPIOX_14)  pinctrl@ff634480
pin 81 (GPIOX_15)  pinctrl@ff634480
pin 82 (GPIOX_16)  pinctrl@ff634480
pin 83 (GPIOX_17)  pinctrl@ff634480
pin 84 (GPIOX_18)  pinctrl@ff634480
pin 85 (GPIOX_19)  pinctrl@ff634480
Linux 3.14 (Android M,N)

Banks:

1
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# cat /sys/kernel/debug/pinctrl/c1109880.pinmux/gpio-ranges

GPIO ranges handled:
0: banks GPIOS [155 - 255] PINS [10 - 110]
0: ao-bank GPIOS [145 - 154] PINS [0 - 9]

Notice: ao-bank means GPIOAO_X gpios

Pins:

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# cat /sys/kernel/debug/pinctrl/c1109880.pinmux/pins
...
pin 5 (GPIOAO_5)
pin 6 (GPIOAO_6)
...
pin 28 (GPIOH_2)
pin 29 (GPIOH_3)
pin 30 (GPIOH_4)
pin 31 (GPIOH_5)
pin 32 (GPIOH_6)
pin 33 (GPIOH_7)
pin 34 (GPIOH_8)
pin 35 (GPIOH_9)
...

例如：获取GPIOH_4, GPIOH_5 and GPIOAO_6的数值：
Number(GPIOH_5) = bank + pin = 155 - 10 + 31= 176
Number(GPIOH_4) = bank + pin = 155 - 10 + 30= 175
Number(GPIOAO_6) = bank + pin = 145 - 0 + 6 = 151

在Android下

GPIO 列表

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PIN         GPIO         Number
PIN37       GPIOH5         432
PIN33       GPIOAO6        502

有两种方式访问GPIO：

  • 通过ADB命令
  • 第三方应用

ADB命令

  • 通过Wi-Fi ADB连接到VIMs
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$ adb connect IP_ADDR
  • 登录VIMs:
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$ adb shell
  • 获取root权限
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$ su
  • 申请GPIO(GPIOH5)
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$ echo 432  > /sys/class/gpio/export
  • 配置GPIO(GPIOH5)为输出
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$ echo out > /sys/class/gpio/gpio432/direction
  • 配置GPIO(GPIOH5)输出高电平
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$ echo 1 >  /sys/class/gpio/gpio432/value
  • 配置GPIO(GPIOH5)输出低电平
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$ echo 0 >  /sys/class/gpio/gpio432/value
  • 配置GPIO(GPIOH5)为输入
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$ echo in > /sys/class/gpio/gpio432/direction
  • 读取GPIO(GPIOH5)电平
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$ cat /sys/class/gpio/gpio432/value
  • 释放GPIO(GPIOH5)
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$ echo 432 > /sys/class/gpio/unexport

第三方应用

  • 获取root权限
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Process mProcess = Runtime.getRuntime().exec("su");
  • 申请GPIO(GPIOH5)
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DataOutputStream os = new DataOutputStream(mProcess.getOutputStream());
os.writeBytes("echo " + 432 + " > /sys/class/gpio/export\n");
  • 配置GPIO(GPIOH5)为输出
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os.writeBytes("echo out > /sys/class/gpio/gpio" + 432 + "/direction\n");
os.writeBytes("echo 1 > /sys/class/gpio/gpio" + 432 + "/value\n");
  • 配置GPIO(GPIOH5)为输入
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os.writeBytes("echo in > /sys/class/gpio/gpio" + 432 + "/direction\n");
  • 读取GPIO(GPIOH5)电平
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Runtime runtime = Runtime.getRuntime(); 
Process process = runtime.exec("cat " + "/sys/class/gpio/gpio" + 432 + "/value");  
InputStream is = process.getInputStream(); 
InputStreamReader isr = new InputStreamReader(is); 
BufferedReader br = new BufferedReader(isr); 
String line ; 
while (null != (line = br.readLine())) { 
 return Integer.parseInt(line.trim()); 
}
  • 释放GPIO(GPIOH5)
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os.writeBytes("echo " + 432 + " > /sys/class/gpio/unexport\n");