linux-kernel - Re: [PATCH 1/3] clk: versatile: Switch to assigned clock parents

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Date:	Mon, 03 Aug 2015 15:01:20 +0100
From:	Pawel Moll <pawel.moll@....com>
To:	Stephen Boyd <sboyd@...eaurora.org>
Cc:	Mike Turquette <mturquette@...libre.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Sudeep Holla <Sudeep.Holla@....com>
Subject: Re: [PATCH 1/3] clk: versatile: Switch to assigned clock parents

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.

Pawel

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