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SubjectRe: [PATCH v2] rtc: zynqmp: Clear alarm interrupt status before interrupt enable
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On 12. 02. 20 11:24, Srinivas Neeli wrote:
> Fix multiple occurring interrupts for alarm interrupt. RTC module doesn't
> clear the alarm interrupt status bit immediately after the interrupt is
> triggered.This is due to the sticky nature of the alarm interrupt status
> register. The alarm interrupt status register can be cleared only after
> the second counter outruns the set alarm value. To fix multiple spurious
> interrupts, disable alarm interrupt in the handler and clear the status
> bit before enabling the alarm interrupt.
>
> Fixes: 11143c19eb57 ("rtc: add xilinx zynqmp rtc driver")
> Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
> ---
> Changes in V2:
> Addressed Michal Simek comments
> - Removed new line in declartion part.
> - Added new line before return.
> ---
> drivers/rtc/rtc-zynqmp.c | 27 +++++++++++++++++++++++----
> 1 file changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c
> index 5786866c09e9..4b1077e2f826 100644
> --- a/drivers/rtc/rtc-zynqmp.c
> +++ b/drivers/rtc/rtc-zynqmp.c
> @@ -38,6 +38,8 @@
>
> #define RTC_CALIB_DEF 0x198233
> #define RTC_CALIB_MASK 0x1FFFFF
> +#define RTC_ALRM_MASK BIT(1)
> +#define RTC_MSEC 1000
>
> struct xlnx_rtc_dev {
> struct rtc_device *rtc;
> @@ -123,11 +125,28 @@ static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
> {
> struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
> + unsigned int status;
> + ulong timeout;
> +
> + timeout = jiffies + msecs_to_jiffies(RTC_MSEC);
> +
> + if (enabled) {
> + while (1) {
> + status = readl(xrtcdev->reg_base + RTC_INT_STS);
> + if (!((status & RTC_ALRM_MASK) == RTC_ALRM_MASK))
> + break;
> +
> + if (time_after_eq(jiffies, timeout)) {
> + dev_err(dev, "Time out occur, while clearing alarm status bit\n");
> + return -ETIMEDOUT;
> + }
> + writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS);
> + }
>
> - if (enabled)
> writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN);
> - else
> + } else {
> writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
> + }
>
> return 0;
> }
> @@ -183,8 +202,8 @@ static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
> if (!(status & (RTC_INT_SEC | RTC_INT_ALRM)))
> return IRQ_NONE;
>
> - /* Clear RTC_INT_ALRM interrupt only */
> - writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS);
> + /* Disable RTC_INT_ALRM interrupt only */
> + writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
>
> if (status & RTC_INT_ALRM)
> rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF);
>

Acked-by: Michal Simek <michal.simek@xilinx.com>

Thanks,
Michal

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