[PATCH v2 05/11] ARM: dt: tegra30: Add device node for APB MISC

[Prashant Gaikwad]

On Friday 04 January 2013 09:30 AM, Stephen Warren wrote:
> On 01/03/2013 08:23 PM, Prashant Gaikwad wrote:
>> On Friday 04 January 2013 08:35 AM, Stephen Warren wrote:
>>> On 01/03/2013 06:48 PM, Prashant Gaikwad wrote:
>>>> On Thursday 03 January 2013 09:41 PM, Stephen Warren wrote:
> ...
>>>>> OK. It sounds like we need a true APB MISC driver then, to abstract the
>>>>> differences; the clock driver really shouldn't be touching the APB MISC
>>>>> registers in all likelihood, unless a subset of the sections you
>>>>> mention
>>>>> above are truly dedicated to clock functionality.
>>>> I don't think it is a good idea to create a driver for APB MISC, all
>>>> registers are used by different drivers.
>>> Well, it's even worse to have a bunch of other drivers randomly trample
>>> on a set of registers they don't own.
>>>
>>>> Only chip id revision registers are used in clock driver.
>>> There are already global variables exposed by the Tegra fuse driver; can
>>> you just read those?
>> It is not about variables or some value, we have to read some apb
>> register to flush the write operation in apb bus before we disable
>> peripheral clock.
>> We are using chip id revision register for this purpose.
> Ah. That's definitely not something the clock driver should be doing
> directly. It's probably OK to add a custom Tegra-specific function to
> some file in arch/arm/mach-tegra to implement this. Even better would be
> a full bus driver for the APB bus, but that's probably too much bloat
> for now.

tegra_init_fuse in arch/arm/mach-tegra/fuse.c is already reading chip id 
revision register, so I can implement one function to read this register 
in fuse.c, which will be used by clock driver and tegra_init_fuse.
But then we need to add it to some header file in include/mach or 
include/linux, where? any suggestion?