linux-kernel - Re: [PATCH 1/2] mmc: add functions to enable/disable aggressive clock gating

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Date:	Wed, 17 Aug 2011 15:19:14 +0300
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	Linus Walleij <linus.walleij@...aro.org>
Cc:	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
	cjb@...top.org
Subject: Re: [PATCH 1/2] mmc: add functions to enable/disable aggressive
 clock gating

On Wed, Aug 17, 2011 at 09:51:31AM +0200, Linus Walleij wrote:
> 
> I would suggest that in all patches using these functions, try
> to replace:
> 
> mmc_host_clk_disable() -> mmc_host_clk_ungate()
> mmc_host_clk_enable() -> mmc_host_clk_gate()
> 

Wow, that is indeed *much* cleaner way of doing this!

One thing is that if I call these from those ios functions,
mmc_host_clk_ungate() will always try to restore the clock
even if there is really no need. Do you see this as a problem?

> Please tell us if this works!

Certainly. I'll try this overnight and see whether it works.

> I understand that the names can be a bit confusing by but
> I think you can convince yourself that what this will do is
> simply increase the refcount host->clk_requests so the
> clock is not gated across these sections.
> 
> If you think the names of the functions are confusing then
> you may rename them, say like this:
> 
> mmc_host_clk_ungate() -> mmc_host_clk_hold()
> mmc_host_clk_gate() -> mmc_host_clk_release()
> 
> Which would make the usecases more clear, I'd be happy
> to ACK a patch for this.

I agree, I'll cook a patch for that also.

Thanks for the comments.
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