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Commit 58c4ed3b authored by Anurag Kumar Vulisha's avatar Anurag Kumar Vulisha Committed by Alexandre Belloni
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rtc: zynqmp: Write Calibration value before setting time 



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: default avatarAnurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent 9092984f

drivers/rtc/rtc-zynqmp.c

+14 −7
Original line number Diff line number Diff line
@@ -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);