RE: [PATCH] OMAP1: camera core : Use platform driver structure

[Komal Shah <komal_shah802003@yahoo.com>]

--- "Zhang, Jian" <jzhang@ti.com> wrote:

> Komal,
> 
> Is there any guideline on the way a driver is registered with LDM?
> e.g.
> via driver_register() or platform_driver_register()? We are now
> always
> using omap_driver_register() which is a wrapper to driver_register().
> 
> Again, is this the trend to move the bulk of init code to probe()
> function?

This one is very tricky question :) May be GregKH and RMK can do better
justice :) 

But I don't understand the need for you to wrap-up the arch specific
register function around driver_register, may be you were defining your
bus type? I also feel, that this wrapper came much before in your
kernel (2.6.9 and .8 series) than the platform_driver addition. 

platform_driver structure does wraps the all the members except the
devid, bus and shared clocks, and devid can be assigned using the
platform_device structure, and bus assignment may not be required as we
connect them under common platform bus.  

And platform_driver_register does call driver_register similar to your
omap_driver_register with few more wrapper functions inside. But as
platform_driver interface wrappers was added recently (Nov'05) by RMK,
which allows to platform device driver methods to be passed a platform
device structure instead a plain device structure and which will
introduce casting in every platform driver. (Last sentence is copied
from RMK's patch comment :) ).

But using driver_register directly doesn't break anything yet.

> 
> If these are what other drivers do, I certainly don't want to see
> camera
> driver being different.
> 

I don't see this as 'must have' kind of things, but if I look back at
what my camera patch gained having those modifications as of current
state of usage for OMAP1610/1710 camera arch, it is 'nothing' except
(void *) casting.

Just FYI.

[1] http://lwn.net/Articles/161236/
[2] http://lwn.net/Articles/158747/
[3] http://lwn.net/Articles/158781/


---Komal Shah
http://komalshah.blogspot.com/

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