Commit 9f5af702 authored by Tomas Melin's avatar Tomas Melin Committed by Alexandre Belloni
Browse files

rtc: zynqmp: rework set_offset 



set_offset was using remainder of do_div as tick_mult which resulted in
wrong offset. Calibration value also assumed builtin calibration default.
Update fract_offset to correctly calculate the value for
negative offset and replace the for loop with division.

Tested-by: default avatarHarini T <harini.t@amd.com>
Signed-off-by: default avatarTomas Melin <tomas.melin@vaisala.com>
Reviewed-by: default avatarHarini T <harini.t@amd.com>
Acked-by: default avatarMichal Simek <michal.simek@amd.com>
Link: https://patch.msgid.link/20260122-zynqmp-rtc-updates-v4-4-d4edb966b499@vaisala.com


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 0f998944

drivers/rtc/rtc-zynqmp.c

+13 −20
Original line number Diff line number Diff line
@@ -208,13 +208,13 @@ static int xlnx_rtc_read_offset(struct device *dev, long *offset) 
static int xlnx_rtc_set_offset(struct device *dev, long offset)

{

	struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);

	unsigned long long rtc_ppb = RTC_PPB;

	unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);

	unsigned char fract_tick = 0;

	int max_tick, tick_mult, fract_offset, fract_part;

	int freq = xrtcdev->freq;

	unsigned int calibval;

	short int  max_tick;

	int fract_offset;

	int fract_data = 0;



	/* Tick to offset multiplier */

	tick_mult = DIV_ROUND_CLOSEST(RTC_PPB, freq);

	if (offset < RTC_MIN_OFFSET || offset > RTC_MAX_OFFSET)

		return -ERANGE;
@@ -223,29 +223,22 @@ static int xlnx_rtc_set_offset(struct device *dev, long offset) 


	/* Number fractional ticks for given offset */

	if (fract_offset) {

		if (fract_offset < 0) {

			fract_offset = fract_offset + tick_mult;

		fract_part = DIV_ROUND_UP(tick_mult, RTC_FR_MAX_TICKS);

		fract_data = fract_offset / fract_part;

		/* Subtract one from max_tick while adding fract_offset */

		if (fract_offset < 0 && fract_data) {

			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;

			}

			fract_data += RTC_FR_MAX_TICKS;

		}

	}



	/* Zynqmp RTC uses second and fractional tick

	 * counters for compensation

	 */

	calibval = max_tick + RTC_CALIB_DEF;



	if (fract_tick)

		calibval |= RTC_FR_EN;

	calibval = max_tick + freq;



	calibval |= (fract_tick << RTC_FR_DATSHIFT);

	if (fract_data)

		calibval |= (RTC_FR_EN | (fract_data << RTC_FR_DATSHIFT));



	writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));