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hi3516cv300: bind rtc-hibvt to the SoC RTC, and judge the time by its counter #125

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Merged
openipc-ai merged 3 commits into from
Oct 20, 2026
Merged

hi3516cv300: bind rtc-hibvt to the SoC RTC, and judge the time by its counter #125

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2caf8ad
arm: dts: hi3516cv300: let rtc-hibvt bind the RTC
openipc-ai Oct 20, 2026
2d792bd
rtc: hibvt: judge the time by its counter, and leave hi3516cv300's CL…
openipc-ai Oct 20, 2026
9c86555
rtc: hibvt: return set_time()'s SPI errors as errors
openipc-ai Oct 20, 2026
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2 changes: 1 addition & 1 deletion arch/arm/boot/dts/hi3516cv300.dtsi
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Original file line number Diff line number Diff line change
Expand Up @@ -641,7 +641,7 @@
};

rtc: rtc@12090000 {
compatible = "hisilicon,hi_rtc";
compatible = "hisilicon,hi35xx-rtc";
Comment thread
qodo-free-for-open-source-projects[bot] marked this conversation as resolved.
interrupts = <2>;
reg = <0x12090000 0x10000>;
};
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49 changes: 36 additions & 13 deletions drivers/rtc/rtc-hibvt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,13 @@ union u_spi_rw {
#define REG_LOCK_STAT BIT(1)
#define REG_LOCK_BYPASS BIT(2)

/*
* A counter that lost every supply restarts from zero and reads as 1970.
* Times before 2000-01-01 are refused both ways, so such a counter reads
* as unset and every time set_time() accepts can be read back.
*/
#define RTC_MIN_VALID_SEC 946684800UL

#define RETRY_CNT 500

#define DATE_TO_SEC(d, h, m, s) (s + m*60 + h*60*60 + d*24*60*60)
Expand Down Expand Up @@ -191,12 +198,15 @@ static int hibvt_rtc_read_time(struct device *dev, struct rtc_time *time)
return ret;
}

if (raw_value & LV_INT_MASK) {
dev_err(dev,
"low voltage detected, date/time is not reliable.\n");
hibvt_spi_write(rtc->regs, RTC_INT_CLR, 1);
return -EINVAL;
}
/*
* Not a verdict on the time: on a hi3516ev300 the flag stays set,
* and returns about half a second after each clear, with a fresh
* backup cell that keeps the counter through a power cut, exactly as
* it did with a flat one. The counter below is what tells. Clear the
* flag by its own bit: writing 1 acknowledged the alarm instead.
*/
if (raw_value & LV_INT_MASK)
hibvt_spi_write(rtc->regs, RTC_INT_CLR, LV_INT_MASK);

ret |= hibvt_spi_rtc_read(rtc->regs, RTC_LORD, &raw_value);
if (raw_value & REG_LOCK_BYPASS)
Expand Down Expand Up @@ -230,6 +240,13 @@ static int hibvt_rtc_read_time(struct device *dev, struct rtc_time *time)
day = (dayl | (dayh << 8));
seconds = DATE_TO_SEC(day, hour, minute, second);

/*
* Report a counter that restarted from zero as unset, so hctosys
* leaves the clock alone instead of stepping it to 1970.
*/
if (seconds < RTC_MIN_VALID_SEC)
return -EINVAL;

rtc_time_to_tm(seconds, time);

return rtc_valid_tm(time);
Expand All @@ -238,7 +255,7 @@ static int hibvt_rtc_read_time(struct device *dev, struct rtc_time *time)
static int hibvt_rtc_set_time(struct device *dev, struct rtc_time *time)
{
struct hibvt_rtc *rtc = dev_get_drvdata(dev);
unsigned char ret = 0;
int ret = 0;
unsigned int days;
unsigned long seconds = 0;
unsigned int cnt = RETRY_CNT;
Expand All @@ -247,6 +264,8 @@ static int hibvt_rtc_set_time(struct device *dev, struct rtc_time *time)
ret = rtc_tm_to_time(time, &seconds);
if (ret)
return ret;
if (seconds < RTC_MIN_VALID_SEC)
return -EINVAL;
days = SEC_TO_DAY(seconds);

ret |= hibvt_spi_rtc_write(rtc->regs, RTC_LR_10MS, 0);
Expand Down Expand Up @@ -486,8 +505,15 @@ static int hibvt_rtc_init(struct hibvt_rtc *rtc)
ret |= hibvt_spi_rtc_write(spi_reg, RTC_IMSC, INT_MSK_DEFAULT);
ret |= hibvt_spi_rtc_write(spi_reg, RTC_SAR_CTRL, LV_CTL_DEFAULT);



#ifndef CONFIG_ARCH_HI3516CV300
/*
* The HiSilicon SDK's own hi3516cv300 RTC driver never writes
* RTC_CLK_CFG, and the register reads 0 on a running board, so leave
* the oscillator settings of that family as they come.
*/
ret |= hibvt_spi_rtc_write(spi_reg, RTC_CLK_CFG, 0x01);
#endif

/* default FREQ COEF */
ret |= hibvt_spi_rtc_write(spi_reg, RTC_FREQ_H, FREQ_H_DEFAULT);
Expand All @@ -500,11 +526,8 @@ static int hibvt_rtc_init(struct hibvt_rtc *rtc)
return ret;
}

if (val & LV_INT_MASK) {
dev_err(&rtc->rtc_dev->dev,
"low voltage detected, date/time is not reliable.\n");
hibvt_spi_write(rtc->regs, RTC_INT_CLR, 1);
}
if (val & LV_INT_MASK)
hibvt_spi_write(rtc->regs, RTC_INT_CLR, LV_INT_MASK);

return ret;
}
Expand Down