On Mon, 23 Feb 2015, Peter Griffin wrote: > On Wed, 18 Feb 2015, Lee Jones wrote: > > > ST's Low Power Controller (LPC) controls two devices; watchdog and RTC. > > Only one of the devices can be used at any one time. This is enforced > > by the correlating MFD driver. This portion of the driver-set controls > > the Real Time Clock. > > <snip> > > > +{ > > + unsigned long flags; > > + > > + spin_lock_irqsave(&rtc->lock, flags); > > + > > + writel(1, rtc->ioaddr + LPC_WDT_OFF); > > + > > + writel(msb, rtc->ioaddr + LPC_LPA_MSB_OFF); > > + writel(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF); > > + writel(1, rtc->ioaddr + LPC_LPA_START_OFF); > > + > > + writel(0, rtc->ioaddr + LPC_WDT_OFF); > > I think all the writel IO accessors in this driver can be replaced > with the *_relaxed variant. This will avoid the overhead of taking a > spinlock in the l2 outer cache part of writel.
Yes, there is no technical reason why we can't use the relaxed variants. Will fix. > > +#ifdef CONFIG_PM_SLEEP > > +static int st_rtc_suspend(struct device *dev) > > +{ > > + struct st_rtc *rtc = dev_get_drvdata(dev); > > + > > + if (device_may_wakeup(dev)) > > + return 0; > > + > > + writel(1, rtc->ioaddr + LPC_WDT_OFF); > > + writel(0, rtc->ioaddr + LPC_LPA_START_OFF); > > + writel(0, rtc->ioaddr + LPC_WDT_OFF); > > Is there a reason for not disabling the IP clock in suspend / resume > functions? There is. It will stop the alarm timer, which is undesirable. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/