[PATCH 4/5] rtc: sc27xx: Add check to see if need to enable the alarm interrupt

From: Baolin Wang
Date: Thu Oct 18 2018 - 04:52:58 EST


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@xxxxxxxxxx>
---
drivers/rtc/rtc-sc27xx.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)

diff --git a/drivers/rtc/rtc-sc27xx.c b/drivers/rtc/rtc-sc27xx.c
index 4ecabe6..72bb002 100644
--- 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) {
--
1.7.9.5