From mboxrd@z Thu Jan  1 00:00:00 1970
From: tony@atomide.com (Tony Lindgren)
Date: Fri, 18 May 2018 06:54:27 -0700
Subject: [PATCH 2/4] omap2: clockdomain: Inroduce cpu_pm notifiers for
 context save/restore
In-Reply-To: <14b0d567-f0cb-72bb-2efc-b21788d9993d@ti.com>
References: <1526483821-25585-1-git-send-email-j-keerthy@ti.com>
 <1526483821-25585-3-git-send-email-j-keerthy@ti.com>
 <20180517214347.GR98604@atomide.com>
 <18c013bb-4f3b-81af-f565-825513e2b501@ti.com>
 <14b0d567-f0cb-72bb-2efc-b21788d9993d@ti.com>
Message-ID: <20180518135427.GT98604@atomide.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

* Tero Kristo <t-kristo@ti.com> [180518 08:41]:
> On 18/05/18 08:57, Keerthy wrote:
> > 
> > 
> > On Friday 18 May 2018 03:13 AM, Tony Lindgren wrote:
> > > * Keerthy <j-keerthy@ti.com> [180516 15:21]:
> > > > Inroduce cpu_pm notifiers for context save/restore. This will be
> > > > needed for am43xx family in case of rtc only mode with ddr in
> > > > self-refresh.
> > > ...
> > > > +static int cpu_notifier(struct notifier_block *nb, unsigned long cmd, void *v)
> > > > +{
> > > > +	switch (cmd) {
> > > > +	case CPU_CLUSTER_PM_ENTER:
> > > > +		if (enable_off_mode)
> > > > +			clkdm_save_context();
> > > > +		break;
> > > > +	case CPU_CLUSTER_PM_EXIT:
> > > > +		if (enable_off_mode)
> > > > +			clkdm_restore_context();
> > > > +		break;
> > > > +	}
> > > > +
> > > > +	return NOTIFY_OK;
> > > > +}
> > > 
> > > Can you do this too only on suspend instead of the cpu notifier?
> > > If you need to call this eventually from cpuidle also then yeah
> > > the notifier makes sense.
> > 
> > Clockdomain under omap2 does not have suspend/resume calls as its still
> > not a driver. The initial version of this patch had save/restore calls
> > directly from pm33xx-core during suspend/resume platform ops are called.
> > 
> > Are you suggesting that?
> 
> I think using cpu notifiers would help in eventual transition of this under
> drivers also, as this doesn't need any custom interfaces to be exported
> around. And, as it seems now, this is only needed for AM43xx at the moment,
> no other SoCs need this for any purpose, even if device off would be
> implemented. Only exception would be if we want to implement RTC+DDR sort of
> functionality on any other SoC.

OK thanks makes sense. Applying all these into omap-for-v4.18/soc.

Regards,

Tony