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From: Kevin Wells on 13 Aug 2010 13:30
Hi Wolfram,

Thanks for continued testing and review of the driver.

> > +
> > +#define LPC32XX_RTC_MATCH0_EN (1 << 0)
> > +#define LPC32XX_RTC_MATCH1_EN (1 << 1)
> > +#define LPC32XX_RTC_ONSW_MATCH0_EN (1 << 2)
> > +#define LPC32XX_RTC_ONSW_MATCH1_EN (1 << 3)
> > +#define LPC32XX_RTC_SW_RESET (1 << 4)
> > +#define LPC32XX_RTC_CNTR_DIS (1 << 6)
> > +#define LPC32XX_RTC_ONSW_FORCE_HIGH (1 << 7)
>
> I would have liked LPC32XX_RTC_CTRL_* as a prefix better as mentioned last
> time. It will do here for the RTC as it doesn't have much registers, though.
>
> > +
> > +#define LPC32XX_RTC_MATCH0_INT_STS (1 << 0)
> > +#define LPC32XX_RTC_MATCH1_INT_STS (1 << 1)
> > +#define LPC32XX_RTC_ONSW_INT_STS (1 << 2)
>
> ditto for including the register name.
>

No problem here..I'll change these.

> > +static int lpc32xx_rtc_alarm_irq_enable(struct device *dev,
> > + unsigned int enabled)
> > +{
> > + struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
> > + u32 tmp;
> > +
> > + spin_lock_irq(&rtc->lock);
> > + tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
> > +
> > + if (enabled) {
> > + rtc->alarm_enabled = 1;
> > + tmp |= LPC32XX_RTC_MATCH0_EN;
> > + } else {
> > + rtc->alarm_enabled = 0;
> > + tmp &= ~LPC32XX_RTC_MATCH0_EN;
> > + }
>
> Maybe 'rtc->alarm_enabled = enabled;' or similar could be used. Didn't check
> thouroughly.
>

I picked this specific approach because the type in the local rtc structure
is unsigned char (matching the struct rtc_wkalrm type) while the passed
parameter 'enabled' is unsigned long. I considered these..
rtc->alarm_enabled = (unsigned char) enabled;
and
rtc->alarm_enabled = !!enabled;

The direct assignment seemed the best approach to avoid some type of cast or
extra logic.

> > + /*
> > + * The RTC is on a seperate power domain and can keep it's state
> > + * across a chip power cycle. If the RTC has never been previously
> > + * setup, then set it up now for the first time.
> > + */
> > + tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
> > + if (rtc_readl(rtc, LPC32XX_RTC_KEY) == LPC32XX_RTC_KEY_ONSW_LOADVAL)
> > +{
>
> This cannot work; it really should be '!=' otherwise the time will be reset at
> every reboot!
>

Hmm, this was a good find. If the key value isn't setup correctly, the
boot ROM will clear the RTC counter on power-on reset. The time isn't being
cleared on my board, so something is setting up the key elsewhere. Your
suggested fix is probably the right fix, but I'll review. Sorry - I won't
get updates for this available until next week.

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