diff options
| author | Tomas Melin <tomas.melin@vaisala.com> | 2026-01-22 13:53:48 +0000 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2026-01-29 16:44:37 +0100 |
| commit | 9f5af70268d679e710a65e5e1b4259789a848309 (patch) | |
| tree | 6b3556761fb1e5baf6186e9da5a514d9c8f79f90 /drivers | |
| parent | 0f9989443faec6ae8b8418ddf39f080c75a23c0d (diff) | |
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: Harini T <harini.t@amd.com>
Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
Reviewed-by: Harini T <harini.t@amd.com>
Acked-by: Michal Simek <michal.simek@amd.com>
Link: https://patch.msgid.link/20260122-zynqmp-rtc-updates-v4-4-d4edb966b499@vaisala.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/rtc/rtc-zynqmp.c | 33 |
1 files changed, 13 insertions, 20 deletions
diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c index c82f4d490fc7..f0f5dc63e254 100644 --- a/drivers/rtc/rtc-zynqmp.c +++ b/drivers/rtc/rtc-zynqmp.c @@ -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)); |