From mboxrd@z Thu Jan  1 00:00:00 1970
From: jszhang@marvell.com (Jisheng Zhang)
Date: Wed, 20 May 2015 20:38:10 +0800
Subject: [PATCH] i2c: designware: separate ops for system_sleep_pm and
 runtime_pm
In-Reply-To: <20150520203430.24edd2a8@xhacker>
References: <1431693099-2292-1-git-send-email-jszhang@marvell.com>
 <20150518082823.GH1490@lahna.fi.intel.com>
 <20150519203242.74617ad6@xhacker>
 <20150519131516.GO1490@lahna.fi.intel.com>
 <20150520193422.73de7d90@xhacker>
 <20150520121506.GU1490@lahna.fi.intel.com>
 <20150520203430.24edd2a8@xhacker>
Message-ID: <20150520203810.2fa5b489@xhacker>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Wed, 20 May 2015 20:34:30 +0800
Jisheng Zhang <jszhang@marvell.com> wrote:

> Dear Mika,
> 
> On Wed, 20 May 2015 15:15:06 +0300
> Mika Westerberg <mika.westerberg@linux.intel.com> wrote:
> 
> > On Wed, May 20, 2015 at 07:34:22PM +0800, Jisheng Zhang wrote:
> > > Sorry for confusion. Considering one platform which doesn't support power off
> > > the i2c host but it can disable the host's clock. So in such platform, when
> > > the host is runtime suspended, its clock is disabled, then i2c_dw_disable() will
> > > hang when s2ram.
> > 
> > Right. This happens also when the platform powers off the device.
> > 
> > > Except using the runtime pm API to ensure the host is in
> > > a correct state, is there any other solution? AFAIK, 'dev->power.direct_complete'
> > > doesn't help such case.
> > 
> > What I had in mind is something like below:
> > 
> > static int i2c_dw_prepare(struct device *dev)
> > {
> > 	return pm_runtime_suspended(dev);
> > }
> > 
> > static void i2c_dw_complete(struct device *dev)
> > {
> > 	if (dev->power.direct_complete)
> > 		pm_request_resume(dev);
> > }
> > 
> > In other words it checks if the device is already runtime suspended and
> > prevents ->suspend() etc. from being called.
> 
> What amazing! I wrote the same code as yours after sending out the last email.
> 
> > 
> > If that does not work (I didn't try as this problem does not exist on
> 
> It works! How to submit the patch? Do you mind if I cook the patch and add
> you signed-off?
> 

PS: If you cook the patch instead,  feel free to add my acked-by and tested-by

Thanks a lot for the direct_complete idea,
Jisheng