如何找出哪个Linux驱动程序占用了我的GPIO？

Question

我的电路板上有一个多用作GPIO的焊盘.当我尝试通过/ sys/class/gpio/export导出它时,我得到了

-sh: echo: write error: Device or resource busy

我的猜测是其他一些司机在我得到这个机会之前要求这个垫子.我怎样才能找到保留它的内容？

Answer 1

在Boundary Devices内核以及其他内核上,您可以使用它cat /sys/kernel/debug/gpio来获取映射的gpios列表,它们的状态以及分配时给出的名称.您可以grep内核源代码名称,并找出抓住它的模块.

root@nitrogen6x:/opt# cat /sys/kernel/debug/gpio 
GPIOs 0-31, platform/209c000.gpio, 209c000.gpio:
 gpio-2   (flexcan-trx-stby    ) out lo    
 gpio-17  (DISP_SCL            ) out lo    

GPIOs 32-63, platform/20a0000.gpio, 20a0000.gpio:
 gpio-33  (sysfs               ) out lo    
 gpio-35  (sysfs               ) in  hi    
 gpio-36  (sysfs               ) in  hi    
 gpio-37  (DISP_SDI            ) out lo    
 gpio-38  (219c000.usdhc cd    ) in  hi    

GPIOs 64-95, platform/20a4000.gpio, 20a4000.gpio:
 gpio-83  (spi_imx             ) out lo    
 gpio-86  (usb_otg_vbus        ) out lo    

GPIOs 96-127, platform/20a8000.gpio, 20a8000.gpio:
 gpio-101 (sysfs               ) in  hi    
 gpio-116 (rst-gpios           ) out lo    

GPIOs 128-159, platform/20ac000.gpio, 20ac000.gpio:

GPIOs 160-191, platform/20b0000.gpio, 20b0000.gpio:
 gpio-175 (wlan-en             ) out lo    
 gpio-176 (bt_rfkill_reset     ) out lo    

GPIOs 192-223, platform/20b4000.gpio, 20b4000.gpio:
 gpio-192 (2198000.usdhc cd    ) in  lo    
 gpio-204 (ehci_reset_gpio     ) out lo    
 gpio-205 (sysfs               ) in  lo    

"

Answer 2

如果您尝试使用cat /sys/kernel/debug/gpio但它不起作用，请先尝试：

mount -t debugfs debugfs /sys/kernel/debug

然后使用上述cat命令

Answer 3

/sys/kernel/debug/gpio是旧版 GPIO 接口的一部分，可能不存在于较新的内核中。替代品是libgpio-toolsgpioinfo工具；这些工具使用较新的字符设备接口来处理 gpios。

如果使用buildroot，请启用BR2_PACKAGE_LIBGPIOD和BR2_PACKAGE_LIBGPIOD_TOOLS。

buildroot:~ $ gpiodetect
gpiochip0 [30200000.gpio] (32 lines)
gpiochip1 [30210000.gpio] (32 lines)
gpiochip2 [30220000.gpio] (32 lines)
gpiochip3 [30230000.gpio] (32 lines)
gpiochip4 [30240000.gpio] (32 lines)
gpiochip5 [0-0023] (16 lines)

buildroot:~ $ gpioinfo
gpiochip0 - 32 lines:
    line   0:      unnamed       unused   input  active-high 
    line   1:      unnamed       unused   input  active-high 
    line   2:      unnamed       unused   input  active-high 
    line   3:      unnamed       unused   input  active-high 
    line   4:      unnamed       unused   input  active-high 
    line   5:      unnamed       unused   input  active-high 
    line   6:      unnamed "pci_usb_sel" output active-high [used]
    line   7:      unnamed       "dio0"   input  active-high [used]
    line   8:      unnamed       unused   input  active-high 
    line   9:      unnamed       "dio1"   input  active-high [used]
    line  10:      unnamed "regulator-usb-otg1" output active-high [used]
(...)