[i2c] I2C/SMbus driver for VT8251 southbridge based keypad

[Rudolf Marek]

Hello

> I would like to write a Linux driver for a keypad, interfaced to VT8251
> Southbridge (i2c/SMBus) interface. The VT8251 sits on VIA X86
> motherboard.

Hmm VT8251 is not yet supported in Linux. We did not succeed to get the
datasheet.  But I think it should be similar to older chipsets. Maybe Honeywell
has it?

> I have Linux 2.6.11.12 kernel running on this board. Basically I need to
> write a Linux driver to capture the keystrokes.

How the keypad issues interrupts to the chipset?

> 1. Whether any such driver already exists In Linux 2.6?

I dont think so.

> 2. When I browsed the /usr/src/linux-2,6/drivers/i2c, I saw lot of
> different drivers like bus driver, chip driver, algo driver, core driver
> and protocol driver etc. Let me know what all I can re-use for my
> requirement and what I need to write from scratch?

It depends how the keypad is connected. You will need the driver for SMBus which
is there for older via SMBus but not this one. We might add the support when we
know that it is same. Do you have a datasheet?

> 3. What all technical details I need to write this keypad driver?

It really depends how the keystrokes are signaled back to the x86 processor.

> 4. Can I know the structure of Linux I2c driver (How it is organized) ?

It is fairlly easy check the i2c-viapro.c or Documentation/i2c/

If you need more questions please feel free to ask.

Regards
Rudolf