diff options
| author | Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com> | 2016-04-12 15:15:45 +0300 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@free-electrons.com> | 2016-05-20 13:33:51 +0300 |
| commit | 58c4ed3ba2e0c97e33affd237dc05738fa55a725 (patch) | |
| tree | 652d1d2f2c20fb3e67f88d9af9aaa3722d8ef6f5 /drivers/rtc | |
| parent | 9092984f1a8440ea52bf53c2d53bf8f5953a5126 (diff) | |
| download | linux-58c4ed3ba2e0c97e33affd237dc05738fa55a725.tar.xz | |
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: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'drivers/rtc')
| -rw-r--r-- | drivers/rtc/rtc-zynqmp.c | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c index 6adb603f29bc..f87f971a72c2 100644 --- a/drivers/rtc/rtc-zynqmp.c +++ b/drivers/rtc/rtc-zynqmp.c @@ -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); |