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path: root/drivers/rtc/rtc-zynqmp.c
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Diffstat (limited to 'drivers/rtc/rtc-zynqmp.c')
-rw-r--r--drivers/rtc/rtc-zynqmp.c74
1 files changed, 61 insertions, 13 deletions
diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c
index 8b28762f0..da18a8ae3 100644
--- a/drivers/rtc/rtc-zynqmp.c
+++ b/drivers/rtc/rtc-zynqmp.c
@@ -45,6 +45,7 @@
#define RTC_INT_SEC BIT(0)
#define RTC_INT_ALRM BIT(1)
#define RTC_OSC_EN BIT(24)
+#define RTC_BATT_EN BIT(31)
#define RTC_CALIB_DEF 0x198233
#define RTC_CALIB_MASK 0x1FFFFF
@@ -55,6 +56,7 @@ struct xlnx_rtc_dev {
void __iomem *reg_base;
int alarm_irq;
int sec_irq;
+ int calibval;
};
static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
@@ -62,21 +64,63 @@ static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long new_time;
- new_time = rtc_tm_to_time64(tm);
+ /*
+ * The value written will be updated after 1 sec into the
+ * seconds read register, so we need to program time +1 sec
+ * to get the correct time on read.
+ */
+ new_time = rtc_tm_to_time64(tm) + 1;
if (new_time > RTC_SEC_MAX_VAL)
return -EINVAL;
+ /*
+ * Writing into calibration register will clear the Tick Counter and
+ * force the next second to be signaled exactly in 1 second period
+ */
+ xrtcdev->calibval &= RTC_CALIB_MASK;
+ writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
+
writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
+ /*
+ * Clear the rtc interrupt status register after setting the
+ * time. During a read_time function, the code should read the
+ * RTC_INT_STATUS register and if bit 0 is still 0, it means
+ * that one second has not elapsed yet since RTC was set and
+ * the current time should be read from SET_TIME_READ register;
+ * otherwise, CURRENT_TIME register is read to report the time
+ */
+ writel(RTC_INT_SEC, xrtcdev->reg_base + RTC_INT_STS);
+
return 0;
}
static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
+ u32 status;
+ unsigned long read_time;
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
- rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_CUR_TM), tm);
+ status = readl(xrtcdev->reg_base + RTC_INT_STS);
+
+ if (status & RTC_INT_SEC) {
+ /*
+ * RTC has updated the CURRENT_TIME with the time written into
+ * SET_TIME_WRITE register.
+ */
+ rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_CUR_TM), tm);
+ } else {
+ /*
+ * Time written in SET_TIME_WRITE has not yet updated into
+ * the seconds read register, so read the time from the
+ * SET_TIME_WRITE instead of CURRENT_TIME register.
+ * Since we add +1 sec while writing, we need to -1 sec while
+ * reading.
+ */
+ read_time = readl(xrtcdev->reg_base + RTC_SET_TM_RD) - 1;
+ rtc_time64_to_tm(read_time, tm);
+ }
return rtc_valid_tm(tm);
}
@@ -120,16 +164,23 @@ static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
return 0;
}
-static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev, u32 calibval)
+static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev)
{
+ u32 rtc_ctrl;
+
+ /* Enable RTC switch to battery when VCC_PSAUX is not available */
+ rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL);
+ rtc_ctrl |= RTC_BATT_EN;
+ writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL);
+
/*
* Based on crystal freq of 33.330 KHz
* set the seconds counter and enable, set fractions counter
* to default value suggested as per design spec
* to correct RTC delay in frequency over period of time.
*/
- calibval &= RTC_CALIB_MASK;
- writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
+ xrtcdev->calibval &= RTC_CALIB_MASK;
+ writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
}
static const struct rtc_class_ops xlnx_rtc_ops = {
@@ -150,11 +201,9 @@ static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
if (!(status & (RTC_INT_SEC | RTC_INT_ALRM)))
return IRQ_NONE;
- /* Clear interrupt */
- writel(status, xrtcdev->reg_base + RTC_INT_STS);
+ /* Clear RTC_INT_ALRM interrupt only */
+ writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS);
- if (status & RTC_INT_SEC)
- rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_UF);
if (status & RTC_INT_ALRM)
rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF);
@@ -166,7 +215,6 @@ static int xlnx_rtc_probe(struct platform_device *pdev)
struct xlnx_rtc_dev *xrtcdev;
struct resource *res;
int ret;
- unsigned int calibvalue;
xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL);
if (!xrtcdev)
@@ -207,11 +255,11 @@ static int xlnx_rtc_probe(struct platform_device *pdev)
}
ret = of_property_read_u32(pdev->dev.of_node, "calibration",
- &calibvalue);
+ &xrtcdev->calibval);
if (ret)
- calibvalue = RTC_CALIB_DEF;
+ xrtcdev->calibval = RTC_CALIB_DEF;
- xlnx_init_rtc(xrtcdev, calibvalue);
+ xlnx_init_rtc(xrtcdev);
device_init_wakeup(&pdev->dev, 1);