Re: [PATCH v3] Input: tsc2005 - Add support for tsc2004

[Michael Welling <mwelling@ieee.org>]

On Fri, Oct 30, 2015 at 09:39:05AM +0900, Mark Brown wrote:
> On Thu, Oct 29, 2015 at 03:23:31PM -0700, Dmitry Torokhov wrote:
> 
> > However, you have regmap in the driver core already. Mark, is it
> > possible to have regmap API also allow doing raw underlying protocol
> > transfer so that consumers could issue command requests without needing
> > to know if they need to do it over i2c or spi or whatever. Or we need a
> > notion of command registers in regmap...
> 
> I don't think it's a good idea to break the encapsulation of the regmap
> and export the raw I/O functionality directly, there seem to be more bad
> ways of using that than good.  The driver must at some point know what
> bus it is dealing with and be able to manage this itself.
> 
> I don't know what "command registers" are.

With this device, if the MSB of the first byte of the transaction is 1 then
a convertor command is encoded in that byte instead of a register address.

So here is my plan:
- Add a function pointer for tsc2005_cmd in the struct tsc2005
- Put the spi and i2c tsc2005_cmd versions in their respective drivers
- Pass the cmd functions to the core via tsc200x_probe

Any objections?
Other review suggestions before I code the revision?
Am I doing too much with a single patch?