[alsa-devel] [PATCH 1/2 v2] ASoC: sh: fsi: Add runtime PM support
broonie at opensource.wolfsonmicro.com
Mon Nov 9 11:58:58 CET 2009
On Mon, Nov 09, 2009 at 11:54:47AM +0900, Kuninori Morimoto wrote:
> This patch add support runtime PM.
> Driver callbacks for Runtime PM are empty because
> the device registers are always re-initialized after
> pm_runtime_get_sync(). The Runtime PM functions replaces the
> clock framework module stop bit handling in this driver.
> Signed-off-by: Kuninori Morimoto <morimoto.kuninori at renesas.com>
Hrm. I'll have to see how this plays with ASoC core pm_runtime support
when that appears. It should be OK as-is, I think.
> + pm_suspend_ignore_children(&pdev->dev, true);
> + pm_runtime_enable(&pdev->dev);
> + pm_runtime_resume(&pdev->dev);
Why pm_suspend_ignore_all_children()? I'd not expect the device to have
any children and if it did it doesn't seem like an entirely safe
> +static int fsi_runtime_nop(struct device *dev)
> + /* Runtime PM callback shared between ->runtime_suspend()
> + * and ->runtime_resume(). Simply returns success.
> + *
> + * This driver re-initializes all registers after
> + * pm_runtime_get_sync() anyway so there is no need
> + * to save and restore registers here.
> + */
> + return 0;
This sets off alarm bells but it's perfectly reasonable, especially with
platforms able to put things into a low power state with no explicit
driver code now they can do power domain style things like SH. I've
CCed in the PM folks since this seems like a perfectly reasonable use
case which ought to be handled more nicely.
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