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rtc: zynqmp: Write Calibration value before setting time

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It is suggested to program CALIB_WRITE register with the calibration
value before updating the SET_TIME_WRITE register, doing so will
clear the Tick Counter and force the next second to be signaled
exactly in 1 second.

Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Anurag Kumar Vulisha 2016-04-12 17:45:45 +05:30 committed by Alexandre Belloni
parent 9092984f1a
commit 58c4ed3ba2
1 changed files with 14 additions and 7 deletions
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21
drivers/rtc/rtc-zynqmp.c
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@ -56,6 +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)
@ -68,6 +69,13 @@ static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
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);
return 0;
@ -121,7 +129,7 @@ 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;
@ -136,8 +144,8 @@ static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev, u32 calibval)
* 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 = {
@ -174,7 +182,6 @@ 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)
@ -215,11 +222,11 @@ 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);