Hi all, Made a small typo mistake , Please ignore this patch. Sorry for the inconvenience caused.
Thanks, Anurag Kumar V > -----Original Message----- > From: Anurag Kumar Vulisha [mailto:anurag.kumar.vuli...@xilinx.com] > Sent: Wednesday, April 20, 2016 8:29 PM > To: Alessandro Zummo <a.zu...@towertech.it>; Alexandre Belloni > <alexandre.bell...@free-electrons.com>; Soren Brinkmann > <sor...@xilinx.com> > Cc: Michal Simek <mich...@xilinx.com>; rtc-li...@googlegroups.com; linux- > arm-ker...@lists.infradead.org; linux-kernel@vger.kernel.org; Punnaiah > Choudary Kalluri <punn...@xilinx.com>; Anirudha Sarangi > <anir...@xilinx.com>; Srikanth Vemula <svem...@xilinx.com>; Srinivas > Goud <sg...@xilinx.com>; Anurag Kumar Vulisha <anura...@xilinx.com> > Subject: [PATCH V3] rtc: zynqmp: Update seconds time programming logic > > We programe RTC time using SET_TIME_WRITE register and read the RTC > current time using CURRENT_TIME register. When we set the time by writing > into SET_TIME_WRITE Register and immediately try to read the rtc time from > CURRENT_TIME register, the previous old value is returned instead of the > new loaded time. This is because RTC takes nearly 1 sec to update the new > loaded value into the CURRENT_TIME register. This behaviour is expected in > our RTC IP. > > This patch updates the driver to read the current time from SET_TIME_WRITE > register instead of CURRENT_TIME when rtc time is requested within an 1sec > period after setting the RTC time. Doing so will ensure the correct time is > given to the user. > > Since there is an delay of 1sec in updating the CURRENT_TIME we are loading > set time +1sec while programming the SET_TIME_WRITE register, doing this > will give correct time without any delay when read from CURRENT_TIME. > > This patch updates the above said. > > Signed-off-by: Anurag Kumar Vulisha <anura...@xilinx.com> > --- > Changes in v3: > 1. Corrected the read time logic > Changes in v2: > 1. Updated the Time programming logic as suggested by Alexandre Belloni > 2. Changed the commit message > --- > drivers/rtc/rtc-zynqmp.c | 44 > ++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 38 insertions(+), 6 deletions(-) > > diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c index > f87f971..c2f4495 100644 > --- a/drivers/rtc/rtc-zynqmp.c > +++ b/drivers/rtc/rtc-zynqmp.c > @@ -64,7 +64,12 @@ 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; > @@ -78,14 +83,43 @@ static int xlnx_rtc_set_time(struct device *dev, struct > rtc_time *tm) > > 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, 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); > } > @@ -166,11 +200,9 @@ 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); > > -- > 2.1.2
