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

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Date:	Fri, 4 Jan 2013 17:26:44 +0530
From:	Laxman Dewangan <ldewangan@...dia.com>
To:	Stephen Warren <swarren@...dotorg.org>
CC:	Prashant Gaikwad <pgaikwad@...dia.com>,
	"mturquette@...aro.org" <mturquette@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH v2 05/11] ARM: dt: tegra30: Add device node for APB MISC

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.

I think individual driver should take care of flushing the write 
operation inplace of clock driver.
Atleast I moved flushing to i2c and spi for these drivers. Polluting 
clock driver here does not make sense here.

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