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SubjectRe: [PATCH 1/3] clk: versatile: Switch to assigned clock parents
On 08/03/2015 07:01 AM, Pawel Moll wrote:
> On Sat, 2015-08-01 at 00:44 +0100, Stephen Boyd wrote:
>> @@ -179,6 +124,15 @@ static void __init clk_sp810_of_setup(struct device_node *node)
>> sp810->timerclken[i].channel = i;
>> sp810->timerclken[i].hw.init = &init;
>>
>> + /*
>> + * If DT isn't setting the parent, force it to be
>> + * the 1 MHz clock without going through the framework.
>> + * We do this before clk_register() so that it can determine
>> + * the parent and setup the tree properly.
>> + */
>> + if (deprecated)
>> + init.ops->set_parent(&sp810->timerclken[i].hw, 1);
>> +
>> sp810->timerclken[i].clk = clk_register(NULL,
>> &sp810->timerclken[i].hw);
>> WARN_ON(IS_ERR(sp810->timerclken[i].clk));
> So that's one thing I've got a (small) problem here...
>
> The above change assumes that SP810 always have 32kHz clock on input 0
> and 1MHz clock on input 1. Yes, this is how it made on VExpress, but it
> doesn't have to be the case. The magic picking up the faster clock was
> added to handle all possible cases.
>
> The bottom line is: if all we care is VExpress than it works, but it's
> still a hack. Personally I don't like it, however I won't nak the patch
> because of this.
>

All current dts files in the kernel tree have 1MHz on input 1, so we
make this change here to set the parent to input 1 if there isn't an
assigned-clock-parents property. Presumably new dts files should have
the new property so that things work properly. I tried to find the
binding document, but it doesn't look to exist, so I didn't have
anything to update.


--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project



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