#24 Patch to support I2c pin configuration via config files

[Rhys Williams]

Update to lcdproc i2c to allow the pin configurations to be specified via
LCDd.conf.

Please find attached 3 patch files.

I have also put up on github:
https://github.com/wilberforce/lcdproc

here is an example config:

Hitachi HD44780 driver

[HD44780]
ConnectionType=i2c
Device=/dev/i2c-1
Port=0x27
Backlight=yes
Size=20x4
DelayBus=false
DelayMult=1
Keypad=no
Speed=0
i2c_line_RS=0x01
i2c_line_RW=0x02
i2c_line_EN=0x04
i2c_line_BL=0x80
i2c_line_D4=0x10
i2c_line_D5=0x20
i2c_line_D6=0x40
i2c_line_D7=0x80
Backlight=yes
BacklightInvert=yes

Thanks
Rhys

[Rhys Williams]

A number of different manufacturers produce piggyback i2c boards that put a i2c port expander designed to go into the back of a 1602 Lcd module.

Here are 2 examples:

http://www.dfrobot.com/index.php?route=product/product&product_id=593#.Vc-tf4rvmJI
http://dx.com/p/lcd1602-adapter-board-w-iic-i2c-interface-black-works-with-official-arduino-boards-216865

The problem is there is no "standard way" to wire the boards. Some have the d4-d7 on the upper nibble, other boards on the lower. Sometime the EN or RS lines are on different pins.

The other issue is that the backlight logic level is wired opposite.