| Message ID | 1455069267-4784-2-git-send-email-ezequiel@vanguardiasur.com.ar (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Ezequiel, On 10 February 2016 at 02:54, Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> wrote: > This commit switches the clockevents one-shot current implementation > to avoid using the prescaler counter. The clockevents timer currently > uses MR0=1, PR=ticks; and after this commit is uses MR0=ticks, PR=0. > > While using the prescaler with PR=1 works fine in one-shot mode, > it seems it doesn't work as expected in periodic mode. > > By using the only match channel register (MR0) for the timer we make > the periodic mode introduction easier, and consistent with one-shot mode. > > Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> > --- > drivers/clocksource/time-lpc32xx.c | 17 ++++++++--------- > 1 file changed, 8 insertions(+), 9 deletions(-) > > diff --git a/drivers/clocksource/time-lpc32xx.c b/drivers/clocksource/time-lpc32xx.c > index 1316876b487a..50d1a63cbe1e 100644 > --- a/drivers/clocksource/time-lpc32xx.c > +++ b/drivers/clocksource/time-lpc32xx.c > @@ -60,14 +60,13 @@ static int lpc32xx_clkevt_next_event(unsigned long delta, > container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev); > > /* > - * Place timer in reset and program the delta in the prescale > - * register (PR). When the prescale counter matches the value > - * in PR the counter register is incremented and the compare > - * match will trigger. After setup the timer is released from > - * reset and enabled. > + * Place timer in reset and program the delta in the match > + * channel 0 (MR0). When the timer counter matches the value > + * in MR0 register the match will trigger an interrupt. > + * After setup the timer is released from reset and enabled. > */ > writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR); > - writel_relaxed(delta, ddata->base + LPC32XX_TIMER_PR); > + writel_relaxed(delta, ddata->base + LPC32XX_TIMER_MR0); > writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR); > > return 0; > @@ -210,13 +209,13 @@ static int __init lpc32xx_clockevent_init(struct device_node *np) > > /* > * Disable timer and clear any pending interrupt (IR) on match > - * channel 0 (MR0). Configure a compare match value of 1 on MR0 > - * and enable interrupt, reset on match and stop on match (MCR). > + * channel 0 (MR0). Clear the prescaler as it's not used. > + * Enable interrupt, reset on match and stop on match (MCR). > */ > writel_relaxed(0, base + LPC32XX_TIMER_TCR); > + writel_relaxed(0, base + LPC32XX_TIMER_PR); > writel_relaxed(0, base + LPC32XX_TIMER_CTCR); > writel_relaxed(LPC32XX_TIMER_IR_MR0INT, base + LPC32XX_TIMER_IR); > - writel_relaxed(1, base + LPC32XX_TIMER_MR0); > writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R | > LPC32XX_TIMER_MCR_MR0S, base + LPC32XX_TIMER_MCR); > > -- There were fewer changes need to switch to MR0 than I thought. Good. Reviewed-by: Joachim Eastwood <manabian@gmail.com> Tested-by: Joachim Eastwood <manabian@gmail.com> Boot tested on EA4357. regards, Joachim Eastwood
diff --git a/drivers/clocksource/time-lpc32xx.c b/drivers/clocksource/time-lpc32xx.c index 1316876b487a..50d1a63cbe1e 100644 --- a/drivers/clocksource/time-lpc32xx.c +++ b/drivers/clocksource/time-lpc32xx.c @@ -60,14 +60,13 @@ static int lpc32xx_clkevt_next_event(unsigned long delta, container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev); /* - * Place timer in reset and program the delta in the prescale - * register (PR). When the prescale counter matches the value - * in PR the counter register is incremented and the compare - * match will trigger. After setup the timer is released from - * reset and enabled. + * Place timer in reset and program the delta in the match + * channel 0 (MR0). When the timer counter matches the value + * in MR0 register the match will trigger an interrupt. + * After setup the timer is released from reset and enabled. */ writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR); - writel_relaxed(delta, ddata->base + LPC32XX_TIMER_PR); + writel_relaxed(delta, ddata->base + LPC32XX_TIMER_MR0); writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR); return 0; @@ -210,13 +209,13 @@ static int __init lpc32xx_clockevent_init(struct device_node *np) /* * Disable timer and clear any pending interrupt (IR) on match - * channel 0 (MR0). Configure a compare match value of 1 on MR0 - * and enable interrupt, reset on match and stop on match (MCR). + * channel 0 (MR0). Clear the prescaler as it's not used. + * Enable interrupt, reset on match and stop on match (MCR). */ writel_relaxed(0, base + LPC32XX_TIMER_TCR); + writel_relaxed(0, base + LPC32XX_TIMER_PR); writel_relaxed(0, base + LPC32XX_TIMER_CTCR); writel_relaxed(LPC32XX_TIMER_IR_MR0INT, base + LPC32XX_TIMER_IR); - writel_relaxed(1, base + LPC32XX_TIMER_MR0); writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R | LPC32XX_TIMER_MCR_MR0S, base + LPC32XX_TIMER_MCR);
This commit switches the clockevents one-shot current implementation to avoid using the prescaler counter. The clockevents timer currently uses MR0=1, PR=ticks; and after this commit is uses MR0=ticks, PR=0. While using the prescaler with PR=1 works fine in one-shot mode, it seems it doesn't work as expected in periodic mode. By using the only match channel register (MR0) for the timer we make the periodic mode introduction easier, and consistent with one-shot mode. Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> --- drivers/clocksource/time-lpc32xx.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-)