Object : The example of LCD1602 i2c proc driver and clock application

Test HW: Linkit 7688

Test SW: openwrit 3.18.109

LCD I2C at 0x27, RTC pcf8563 at 0x51

Usage:

copy lcd1602i2c2 to openwrt/package/kernel
make menuconfig
	select
	Kernel modules
	Other modules
	[*]kmod-lcd1602i2c2
make package/lcd1602i2c2/compile V=s
opkg install ipk to Linkit 7688

echo -e -n "\n0123456" > /proc/LCDI2C
The LCD1602 shwo 0123456

echo -e -n "\b" > /proc/LCDI2C
The LCD1602 turn off backlight

echo -e -n "\a" > /proc/LCDI2C
The LCD1602 turn on backlight

---

copy clock_gcat to openwrt/package/
copy clock_gcat_set_autorun to openwrt/package/
make menuconfig
	select
	Utilities
	[*]clock_gcat
	[*]clock_gcat_set_autorun
make package/clock_gcat/compile V=s
make package/clock_gcat_set_autorun/compile V=s
opkg install ipk to Linkit 7688

reboot Linkit 7688 and LCD show time.

Install from ipk

opkg install --force-depends kmod-lcd1602i2c_3.18.109-ramips-1_ramips_24kec.ipk		
opkg install clock_gcat_1_ramips_24kec.ipk  
opkg install clock_gcat_set_autorun_1_ramips_24kec.ipk  

reboot Linkit 7688 and LCD show time.  

---

RTC class:

Linkit7688, openwrt 15.05.1, linux 3.18.109 
預設RTC class沒開,需要啟用 
make kernel_menuconfig 
Device Driver 
	[]Real Time Clock 


預設i2c_ralink而不是I2C, 需要啟用 
make kernel_menuconfig 
	Device Driver 
		I2C support 
			[]I2C support 
Real Time Clock內,才會出現 ds1307 / pcf8563可選. 
編出rtc-ds1307.ko / rtc-pcf8563.ko後,要把I2C關掉, 不然系統開機時會與i2c_ralink沖突而報錯. 

開機就掛載rtc-ds1307.ko 
把rtc-ds1307.ko
拷到 /lib/modules/3.18.109 
在/etc/modules.d內,加檔案60-rtc 
內容為一行字串 
rtc-ds1307 

若不想動到device tree, 可用下列方法掛載 
echo ds1307 0x68 > /sys/bus/i2c/devices/i2c-0/new_device 
echo pcf8563 0x51 > /sys/bus/i2c/devices/i2c-0/new_device 
就會出現/dev/rtc0 
程式hwclock就可以讀寫RTC 

開機就由RTC設定系統時間 :
沒有RTC時, openwrt預設是用/etc/init.d/sysfixtime讀取/etc內檔案的時間,以最新的檔案時間設定為系統時間, 
可以把二行字串放到這檔案內 
echo ds1307 0x68 > /sys/bus/i2c/devices/i2c-0/new_device 
hwclock -s 

或是/etc/rc.local 

If the code help you, how about buy street cat a fish can ?