rk3288 升级后用gpio输出提示升级完成

Platform: ROCKCHIP
OS: Android 6.0
Kernel: 3.10.92
由于板子没有lcd无法得知sd卡升级是否完成,因此使用LED显示.
Recovery中升级完成后控制GPIO输出高电平点亮LED.
系统自带GPIO控制驱动:
内核已经自带了通用GPIO驱动,可以直接在用户空间操作.
路径: /sys/class/gpio
root@rk3288:/sys/class/gpio # ls
export
gpiochip0
gpiochip120
gpiochip152
gpiochip184
gpiochip216
gpiochip24
gpiochip248
gpiochip280
gpiochip56
gpiochip88
unexport
比如我要操作GPIO8_A6作为高电平输出有效, 那么有以下问题:
1. 对应的gpio number是多少呢?
2. 如何设置成输出
3. 如何输出高电平
问题1:
可以通过/sys/kernel/debug/gpio查询信息:
root@rk3288:/sys/kernel/debug # cat gpio                                      
//snip
GPIOs 184-215, platform/ff770000.pinctrl, gpio6:
gpio-193 (?                   ) in  hi
gpio-194 (?                   ) in  hi
GPIOs 216-247, platform/ff770000.pinctrl, gpio7:
gpio-218 (enable              ) out hi
gpio-219 (lcd_en              ) in  hi
gpio-220 (lcd_cs              ) in  hi
gpio-221 (gslX680 wake pin    ) out hi
gpio-222 (gslX680 irq pin     ) out lo
gpio-223 (headset_gpio        ) in  hi
gpio-233 (?                   ) in  hi
gpio-234 (?                   ) in  hi
GPIOs 248-279, platform/ff770000.pinctrl, gpio8:
GPIOs 280-311, platform/ff770000.pinctrl, gpio15:
可以看到gpio8是以nubmer为248开始, 那么GPIO8_A6就是 248 +　6 = 254   。如果是GPIO8_B6 那么就是是 248 + +14
接下来就可以导出gpio了
root@rk3288:/sys/class/gpio # echo 254 > export                         
root@rk3288:/sys/class/gpio # ls
export
gpio254
......
问题2
root@rk3288:/sys/class/gpio/gpio254 # echo out > direction                    
root@rk3288:/sys/class/gpio/gpio254 # cat direction                           
out
问题3:
root@rk3288:/sys/class/gpio/gpio254 # echo 1 > value                          
root@rk3288:/sys/class/gpio/gpio254 # cat value                               
1
解决方法:
init.rc
[kris@:~/rk3288/device/rockchip/common/recovery/etc]$ g df
diff --git a/recovery/etc/init.rc b/recovery/etc/init.rc
index efe2a5d..75d7554 100755
--- a/recovery/etc/init.rc
+++ b/recovery/etc/init.rc
@@ -85,6 +85,12 @@ on late-init
on property:sys.powerctl=*
    powerctl ${sys.powerctl}
+#Kris, 170407, GPIO8_A6 -> gpio254, used to inform sd upgrade complete.
+on property:sdupgrade.complete=true
+       write /sys/class/gpio/export 254
+       write /sys/class/gpio/gpio254/direction out
+       write /sys/class/gpio/gpio254/value 1
+
service ueventd /sbin/ueventd
     critical
     seclabel u:r:ueventd:s0
recovery.cpp
[kris@:~/rk3288/bootable/recovery]$ g df
diff --git a/recovery.cpp b/recovery.cpp
index 8299672..a0edc15 100755
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -2285,6 +2285,10 @@ HANDLE_STATUS :
         strcat(kernellogPath, "/kernel.txt");
         save_kernel_log(kernellogPath);
         #endif
+
+       //Kris, 170407, light led on after sd upgrade complete.
+       property_set("sdupgrade.complete", "true");
+
                if (bSDMounted)
             checkSDRemoved();

参考：

https://blog.csdn.net/kris_fei/article/details/69553422