From mboxrd@z Thu Jan  1 00:00:00 1970
From: JeffyChen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
Subject: Re: [PATCH v4 08/13] iommu/rockchip: Control clocks needed to access
	the IOMMU
Date: Mon, 22 Jan 2018 12:09:30 +0800
Message-ID: <5A6563FA.8080602@rock-chips.com>
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To: Randy Li <randy.li-TNX95d0MmH7DzftRWevZcw@public.gmane.org>, Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, tfiga-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org
Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, jcliang-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
List-Id: devicetree@vger.kernel.org

Hi Randy,

On 01/22/2018 10:15 AM, JeffyChen wrote:
> Hi Randy,
>
> On 01/22/2018 09:18 AM, Randy Li wrote:
>>>
>> Also the power domain driver could manage the clocks as well, I would
>> suggest to use pm_runtime_*.
>
> actually the clocks required by pm domain may not be the same as what we
> want to control here, there might be some clocks only be needed when
> accessing mmu registers.
>
> but i'm not very sure about that, will confirm it with Simon Xue.

confirmed with Simon, there might be some iommus don't have a pd, and 
the CONFIG_PM could be disabled.

so it might be better to control clocks in iommu driver itself.