linux-kernel - Re: [PATCH 03/10] msm: iommu: Convert to clk

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Date:	Tue, 25 Sep 2012 13:16:40 -0700
From:	Stephen Boyd <sboyd@...eaurora.org>
To:	Saravana Kannan <skannan@...eaurora.org>
CC:	David Brown <davidb@...eaurora.org>,
	Daniel Walker <dwalker@...o99.com>,
	Bryan Huntsman <bryanh@...eaurora.org>,
	linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 03/10] msm: iommu: Convert to clk_prepare/unprepare

On 09/24/12 15:32, Saravana Kannan wrote:
>> @@ -275,8 +275,11 @@ static int msm_iommu_remove(struct
>> platform_device *pdev)
>>
>>       drv = platform_get_drvdata(pdev);
>>       if (drv) {
>> -        if (drv->clk)
>> +        if (drv->clk) {
>> +            clk_unprepare(drv->clk);
>>               clk_put(drv->clk);
>> +        }
>> +        clk_unprepare(drv->pclk);
>
>
> Are these changes right? Every other clk API change in this patch is
> using the combined prepare_enable/disable_unprepare() calls. So, when
> would we end up at this location with the clocks prepared but not
> enabled?
>
> Also, what if the device gets probed and then immediately removed.
> Will it work correctly?
>

It should work correctly. If you look at the bottom of msm_iommu_probe()
you see that it call clk_disable() and doesn't unprepare the clock. So
if the driver is unbound the clocks should be disabled but still prepared.

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