From: Michal Simek <michal.simek@xilinx.com>
To: Srinivas Neeli <srinivas.neeli@xilinx.com>,
a.zummo@towertech.it, alexandre.belloni@bootlin.com,
michal.simek@xilinx.com, sgoud@xilinx.com, shubhraj@xilinx.com
Cc: linux-rtc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, git@xilinx.com,
Srinivas Goud <srinivas.goud@xilinx.com>
Subject: Re: [PATCH] rtc: zynqmp: Add calibration set and get support
Date: Mon, 24 Feb 2020 12:16:36 +0100 [thread overview]
Message-ID: <00b3e6dd-50d6-f5a7-a861-e6db91f6eafb@xilinx.com> (raw)
In-Reply-To: <1582191106-30431-1-git-send-email-srinivas.neeli@xilinx.com>
On 20. 02. 20 10:31, Srinivas Neeli wrote:
> ZynqMp RTC controller has a calibration feature to compensate
> time deviation due to input clock inaccuracy.
> Set and get calibration API's are used for setting and getting
> calibration value from the controller calibration register.
>
> Signed-off-by: Srinivas Goud <srinivas.goud@xilinx.com>
> Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
> ---
> drivers/rtc/rtc-zynqmp.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 78 insertions(+)
>
> diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c
> index 4b1077e2f826..b4118e9e4fcc 100644
> --- a/drivers/rtc/rtc-zynqmp.c
> +++ b/drivers/rtc/rtc-zynqmp.c
> @@ -40,6 +40,12 @@
> #define RTC_CALIB_MASK 0x1FFFFF
> #define RTC_ALRM_MASK BIT(1)
> #define RTC_MSEC 1000
> +#define RTC_FR_MASK 0xF0000
> +#define RTC_SEC_MAX_VAL 0xFFFFFFFF
> +#define RTC_FR_MAX_TICKS 16
> +#define RTC_OFFSET_MAX 150000
> +#define RTC_OFFSET_MIN -150000
> +#define RTC_PPB 1000000000LL
>
please use tabs here.
> struct xlnx_rtc_dev {
> struct rtc_device *rtc;
> @@ -184,12 +190,84 @@ static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev)
> writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
> }
>
> +static int xlnx_rtc_read_offset(struct device *dev, long *offset)
> +{
> + struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
> + long offset_val;
> + unsigned int reg;
> + unsigned int tick_mult = RTC_PPB / xrtcdev->calibval;
> +
> + reg = readl(xrtcdev->reg_base + RTC_CALIB_RD);
> +
> + /* Offset with seconds ticks */
> + offset_val = reg & RTC_TICK_MASK;
> + offset_val = offset_val - xrtcdev->calibval;
> + offset_val = offset_val * tick_mult;
> +
> + /* Offset with fractional ticks */
> + if (reg & RTC_FR_EN)
> + offset_val += ((reg & RTC_FR_MASK) >> RTC_FR_DATSHIFT)
> + * (tick_mult / RTC_FR_MAX_TICKS);
> + *offset = offset_val;
> +
> + return 0;
> +}
> +
> +static int xlnx_rtc_set_offset(struct device *dev, long offset)
> +{
> + struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
> + short int max_tick;
> + unsigned char fract_tick = 0;
> + unsigned int calibval;
double space.
> + int fract_offset;
> + unsigned int tick_mult = RTC_PPB / xrtcdev->calibval;
> +
> + /* Make sure offset value is within supported range */
> + if (offset < RTC_OFFSET_MIN || offset > RTC_OFFSET_MAX)
> + return -ERANGE;
> +
> + /* Number ticks for given offset */
> + max_tick = div_s64_rem(offset, tick_mult, &fract_offset);
> +
> + /* Number fractional ticks for given offset */
> + if (fract_offset) {
> + if (fract_offset < 0) {
> + fract_offset = fract_offset + tick_mult;
> + max_tick--;
> + }
> + if (fract_offset > (tick_mult / RTC_FR_MAX_TICKS)) {
> + for (fract_tick = 1; fract_tick < 16; fract_tick++) {
> + if (fract_offset <=
> + (fract_tick *
> + (tick_mult / RTC_FR_MAX_TICKS)))
> + break;
> + }
> + }
> + }
> +
> + /* Zynqmp RTC uses second and fractional tick
> + * counters for compensation
> + */
> + calibval = max_tick + xrtcdev->calibval;
> +
> + if (fract_tick)
> + calibval |= RTC_FR_EN;
> +
> + calibval |= (fract_tick << RTC_FR_DATSHIFT);
here is double space.
> +
> + writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
> +
> + return 0;
> +}
> +
> static const struct rtc_class_ops xlnx_rtc_ops = {
> .set_time = xlnx_rtc_set_time,
> .read_time = xlnx_rtc_read_time,
> .read_alarm = xlnx_rtc_read_alarm,
> .set_alarm = xlnx_rtc_set_alarm,
> .alarm_irq_enable = xlnx_rtc_alarm_irq_enable,
> + .read_offset = xlnx_rtc_read_offset,
> + .set_offset = xlnx_rtc_set_offset,
use tabs as is done above.
> };
>
> static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
>
The rest looks good.
Thanks,
Michal
next prev parent reply other threads:[~2020-02-24 11:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 9:31 [PATCH] rtc: zynqmp: Add calibration set and get support Srinivas Neeli
2020-02-24 11:16 ` Michal Simek [this message]
2020-02-25 1:19 ` kbuild test robot
2020-02-27 11:45 ` Alexandre Belloni
2021-07-14 8:08 Srinivas Neeli
2021-08-09 10:05 ` Srinivas Neeli
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