From mboxrd@z Thu Jan 1 00:00:00 1970 From: Javier Martinez Canillas Subject: Re: [PATCH v4 07/14] mfd: Add driver for Maxim 77802 Power Management IC Date: Thu, 26 Jun 2014 18:18:43 +0200 Message-ID: <53AC47E3.2030306@collabora.co.uk> References: <1403723019-6212-1-git-send-email-javier.martinez@collabora.co.uk> <1403723019-6212-8-git-send-email-javier.martinez@collabora.co.uk> <1403775093.27156.13.camel@AMDC1943> <53AC003E.2010608@collabora.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Doug Anderson Cc: Krzysztof Kozlowski , Lee Jones , Samuel Ortiz , Mark Brown , Mike Turquette , Liam Girdwood , Alessandro Zummo , Kukjin Kim , Olof Johansson , Sjoerd Simons , Daniel Stone , Tomeu Vizoso , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , linux-samsung-soc , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: devicetree@vger.kernel.org Hello Doug, On 06/26/2014 06:12 PM, Doug Anderson wrote: > Javier, > > On Thu, Jun 26, 2014 at 4:13 AM, Javier Martinez Canillas > wrote: >>>> + >>>> +#ifdef CONFIG_PM_SLEEP >>>> +static int max77802_suspend(struct device *dev) >>>> +{ >>>> + struct i2c_client *i2c = container_of(dev, struct i2c_client, dev); >>>> + struct max77802_dev *max77802 = i2c_get_clientdata(i2c); >>>> + >>>> + if (device_may_wakeup(dev)) >>>> + enable_irq_wake(max77802->irq); >>>> + >>>> + disable_irq(max77802->irq); >>> >>> Can you add short comment why this is needed? I know why but just for >>> future generations which will wonder: "why do we need to disable the IRQ >>> while suspending?" :). Especially that this is rather a workaround for >>> issue in other driver (I2C bus). >>> >> >> Good idea, I'll add a comment here on next version so code archaeologists can >> figure out what what's going on here. > > Is the disable_irq() needed if you have > ? > Probably not but I added the following comment: /* * The IRQ must be disabled during suspend since due wakeup * ordering issues it may be possible that the I2C controller * is still suspended when the interrupt happens so the IRQ * handler will fail to read the I2C bus. */ disable_irq(max77802->irq); since in theory this PMIC can be used in other SoCs besides Exynos5420/Exynos5800 and it may be possible that the I2C controller driver for these other SoCs may not resume at noirq time. But on a second thought, this PMIC seems to be designed specially for these two Exynos SoCs so I guess it's safe to assume that it is not needed? Best regards, Javier -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html