rtc: sc27xx: Add check to see if need to enable the alarm interrupt

The RTC interrupt enable register is not put in always-power-on region
supplied by VDDRTC, so we should check if we need enable the alarm
interrupt when system booting.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/rtc/rtc-sc27xx.c b/drivers/rtc/rtc-sc27xx.c
index 4ecabe6..72bb002 100644 (file)
--- a/drivers/rtc/rtc-sc27xx.c
+++ b/drivers/rtc/rtc-sc27xx.c
@@ -563,6 +563,32 @@ static int sprd_rtc_check_power_down(struct sprd_rtc *rtc)
        return 0;
 }
 
+static int sprd_rtc_check_alarm_int(struct sprd_rtc *rtc)
+{
+       u32 val;
+       int ret;
+
+       ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_SPG_VALUE, &val);
+       if (ret)
+               return ret;
+
+       /*
+        * The SPRD_RTC_INT_EN register is not put in always-power-on region
+        * supplied by VDDRTC, so we should check if we need enable the alarm
+        * interrupt when system booting.
+        *
+        * If we have set SPRD_RTC_POWEROFF_ALM_FLAG which is saved in
+        * always-power-on region, that means we have set one alarm last time,
+        * so we should enable the alarm interrupt to help RTC core to see if
+        * there is an alarm already set in RTC hardware.
+        */
+       if (!(val & SPRD_RTC_POWEROFF_ALM_FLAG))
+               return 0;
+
+       return regmap_update_bits(rtc->regmap, rtc->base + SPRD_RTC_INT_EN,
+                                 SPRD_RTC_ALARM_EN, SPRD_RTC_ALARM_EN);
+}
+
 static int sprd_rtc_probe(struct platform_device *pdev)
 {
        struct device_node *node = pdev->dev.of_node;
@@ -596,6 +622,13 @@ static int sprd_rtc_probe(struct platform_device *pdev)
        rtc->dev = &pdev->dev;
        platform_set_drvdata(pdev, rtc);
 
+       /* check if we need set the alarm interrupt */
+       ret = sprd_rtc_check_alarm_int(rtc);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to check RTC alarm interrupt\n");
+               return ret;
+       }
+
        /* check if RTC time values are valid */
        ret = sprd_rtc_check_power_down(rtc);
        if (ret) {