Re: [PATCH 6/9] ARM: OMAP2+: Fix external clock support for dmtimers

[Jon Hunter <jon-hunter@ti.com>]

Hi Benoit,

On 05/21/2012 11:58 AM, Cousson, Benoit wrote:
> Hi Jon,
> 
> On 5/16/2012 1:35 AM, Jon Hunter wrote:
>> From: Jon Hunter<jon-hunter@ti.com>
>>
>> Currently, the dmtimer determines whether an timer can support an
>> external
>> clock source (sys_altclk) for driving the timer by the IP version. Only
>> OMAP24xx devices can support an external clock source, but the IP version
>> between OMAP24xx and OMAP3xxx is common and so this incorrectly indicates
>> that OMAP3 devices can use an external clock source.
>>
>> Rather than use the IP version, use the OMAP_TIMER_HAS_ALTCLK flag added
>> to the HWMOD timer device attributes. By doing this, this allows us to
>> eliminate the "timer_ip_version" variable passed as part of the
>> platform data.
> 
> I do not think this is the right way to handle that. The timer IP itself
> does have only one input clock.
> This is the mux before that clock that will have several inputs
> depending on the SoC revision.
> So this is purely PRCM stuff and has nothing to do with the timer IP
> itself.
> 
> The OMAP_TIMER_HAS_ALTCLK is thus not a timer IP information and cannot
> be stored inside timer hwmod.

Ok, understood.

> In fact, if the alt clock is there the "alt_clk" alias will be there and
> thus you can use the clk_get(dev, "alt_clk") to figure out if the clock
> is there or not.

Ok, I can do this and did think about it, but then wondered why it had
been done this way in the first place? However, I prefer this approach
too as it simplifies the code :-)

So I modify how this is handled.

Cheers
Jon