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 devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
