From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH] mfd: as3722: Handle interrupts on suspend Date: Fri, 20 Nov 2015 10:30:18 +0000 Message-ID: <20151120103018.GD3098@x1> References: <1447942983-31810-1-git-send-email-jonathanh@nvidia.com> <564EF174.4020300@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <564EF174.4020300@nvidia.com> Sender: linux-kernel-owner@vger.kernel.org To: Jon Hunter Cc: linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org List-Id: linux-tegra@vger.kernel.org On Fri, 20 Nov 2015, Jon Hunter wrote: >=20 > On 19/11/15 14:23, Jon Hunter wrote: > > The as3722 device is registered as an irqchip and the as3722-rtc in= terrupt > > is one of it's interrupt sources. When using the as3722-rtc as a wa= ke-up > > device from suspend, the following is seen: > >=20 > > PM: Syncing filesystems ... done. > > Freezing user space processes ... (elapsed 0.001 seconds) done. > > Freezing remaining freezable tasks ... (elapsed 0.001 seconds) do= ne. > > Suspending console(s) (use no_console_suspend to debug) > > PM: suspend of devices complete after 161.119 msecs > > PM: late suspend of devices complete after 1.048 msecs > > PM: noirq suspend of devices complete after 0.756 msecs > > Disabling non-boot CPUs ... > > CPU1: shutdown > > CPU2: shutdown > > CPU3: shutdown > > Entering suspend state LP1 > > Enabling non-boot CPUs ... > > CPU1 is up > > CPU2 is up > > CPU3 is up > > PM: noirq resume of devices complete after 0.487 msecs > > as3722 4-0040: Failed to read IRQ status: -16 > > as3722 4-0040: Failed to read IRQ status: -16 > > as3722 4-0040: Failed to read IRQ status: -16 > > as3722 4-0040: Failed to read IRQ status: -16 > > ... > >=20 > > The reason why the as3722 interrupt status cannot be read is becaus= e the > > as3722 interrupt is not masked during suspend and when the as3722-r= tc > > interrupt occurs, to wake-up the device, the interrupt is seen befo= re the > > i2c controller has been resumed in order to read the as3722 interru= pt > > status. > >=20 > > The as3722-rtc driver sets it's interrupt as a wake-up source durin= g > > suspend, which gets propagated to the parent as3722 interrupt. Howe= ver, > > the as3722-rtc driver cannot disable it's interrupt during suspend > > otherwise we would never be woken up and so the as3722 must disable= it's > > interrupt instead. > >=20 > > Fix this by disabling the as3722 interrupt during suspend. To ensur= e that > > a wake-up event from the as3722 is not missing, enable the as3722 i= nterrupt > > as a wake-up source before disabling the interrupt on entering susp= end. > >=20 > > Signed-off-by: Jon Hunter > > --- > > drivers/mfd/as3722.c | 29 +++++++++++++++++++++++++++++ > > 1 file changed, 29 insertions(+) > >=20 > > diff --git a/drivers/mfd/as3722.c b/drivers/mfd/as3722.c > > index 924ea90494ae..8ee6e4008276 100644 > > --- a/drivers/mfd/as3722.c > > +++ b/drivers/mfd/as3722.c > > @@ -405,6 +405,8 @@ static int as3722_i2c_probe(struct i2c_client *= i2c, > > goto scrub; > > } > > =20 > > + device_init_wakeup(as3722->dev, true); > > + > > dev_dbg(as3722->dev, "AS3722 core driver initialized successfully= \n"); > > return 0; > > =20 > > @@ -422,6 +424,28 @@ static int as3722_i2c_remove(struct i2c_client= *i2c) > > return 0; > > } > > =20 > > +static int as3722_i2c_suspend(struct device *dev) > > +{ > > + struct as3722 *as3722 =3D dev_get_drvdata(dev); > > + > > + if (device_may_wakeup(dev)) > > + enable_irq_wake(as3722->chip_irq); > > + disable_irq(as3722->chip_irq); > > + > > + return 0; > > +} > > + > > +static int as3722_i2c_resume(struct device *dev) > > +{ > > + struct as3722 *as3722 =3D dev_get_drvdata(dev); > > + > > + if (device_may_wakeup(dev)) > > + disable_irq_wake(as3722->chip_irq); > > + enable_irq(as3722->chip_irq); >=20 > I just realised that I should enable the irq before disabling the wak= eup > here. I will fix that. >=20 > I will wait to send out a V2 for a couple days in case there are any > other comments. Easier for everyone if you just resend. --=20 Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog