redis的io多路復用機制，實時查看Linux IO復用情況

1、查找 pinmux-pins

rk3288:/ # busybox find /d/pinctrl -name pinmux-pins
/d/pinctrl/pinctrl/pinmux-pins

2、cat pinmux-pins

rk3399_all:/ # cat /d/pinctrl/pinctrl/pinmux-pins                              
Pinmux settings per pin
Format: pin (name): mux_owner gpio_owner hog?
pin 0 (gpio0-0): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 1 (gpio0-1): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 2 (gpio0-2): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 3 (gpio0-3): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 4 (gpio0-4): (MUX UNCLAIMED) gpio0:4
pin 5 (gpio0-5): (MUX UNCLAIMED) gpio0:5
pin 6 (gpio0-6): ff420030.pwm (GPIO UNCLAIMED) function pwm3a group pwm3a-pin
pin 7 (gpio0-7): fe320000.dwmmc (GPIO UNCLAIMED) function sdmmc group sdmcc-cd
pin 8 (gpio0-8): (MUX UNCLAIMED) (GPIO UNCLAIMED)
pin 9 (gpio0-9): (MUX UNCLAIMED) gpio0:9
pin 10 (gpio0-10): (MUX UNCLAIMED) gpio0:10

3、還可以從dtb查看是否有GPIO的復用配置，我們dts的配置使用，最終都會編譯到這里去。

vi arch/arm64/boot/dts/rockchip/.rk3399-box-rev2-hdmi.dtb.dts.tmp