Writing I2C chip driver in combination with other structure

Hi All,

I have written and seen lot of code of i2c drivers for input subsystem
devices and much familiar with that. Now I have started writing driver
for one chip that is not exactly type of input device. So, little bit
confused about how should be the driver architecture so that it will
be a clean code yet simple.  Following text and diagram explains short
functional description of chip.


Chip Interface :-
==========


        ======                   =======
        |             |                    |   I2C         |
        |             | ----- I2C ---  |  Device    |
        |    ARM  | ----- Bus --  |  With rw    | ------------ Input Connect
        |             |                    |   regs       |
        |             | ---------------|                 |
        ======     INTR       =======

So above picture depicts how chip is interfaced to ARM CPU. This chip
has some registers which are rw and can be used to read certain
information from chip or to program it. This chip is capable of giving
intterupt to CPU. This chip has one input which it like some cable
connection. It detects when this cable is connected and raises the
interrupt.

Functionality Expected in Driver:-
===================

1. Driver should communicate with chip over I2C.
2. Driver should report event to user space upon receiving interrupt
from I2C device.
3. Driver should be capable of programming I2C chip @ the time of
initialization as well should be capable of changing registers as and
when Linux User Space application wants to.

What I have thought of:-

36 more lines

On Fri, 2012-07-20 at 16:24 +0530, aurum spark wrote:

Hi All,

I have written and seen lot of code of i2c drivers for input subsystem
devices and much familiar with that. Now I have started writing driver
for one chip that is not exactly type of input device. So, little bit
confused about how should be the driver architecture so that it will
be a clean code yet simple.  Following text and diagram explains short
functional description of chip.


Chip Interface :-
==========


        ======                   =======
        |             |                    |   I2C         |
        |             | ----- I2C ---  |  Device    |
        |    ARM  | ----- Bus --  |  With rw    | ------------ Input Connect
        |             |                    |   regs       |
        |             | ---------------|                 |
        ======     INTR       =======

So above picture depicts how chip is interfaced to ARM CPU. This chip
has some registers which are rw and can be used to read certain
information from chip or to program it. This chip is capable of giving
intterupt to CPU. This chip has one input which it like some cable
connection. It detects when this cable is connected and raises the
interrupt.

Functionality Expected in Driver:-
===================

1. Driver should communicate with chip over I2C.
2. Driver should report event to user space upon receiving interrupt
from I2C device.
3. Driver should be capable of programming I2C chip @ the time of
initialization as well should be capable of changing registers as and
when Linux User Space application wants to.

What I have thought of:-

20 more quoted lines

What does this chip do and why does it need to do I2C transaction based
on application demand?

b) We can provide sysfs interface to user space to send commands to
i2c device as and when required at runtime.


As per my thoughts I am not sure shall I make this as input device
just to report one event upon getting interrupt from device. Also will
it be ok to have this as char driver in combination with i2c chip
driver ?
Please guide me and take me to correct source or documentation or to
source code of some driver for this kind of device. Does i2c support
ops like fbops ?


Regards,
 ~/Aurum

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