diff mbox series

[v8,04/11] rtc: sun6i: Add support for linear day storage

Message ID 20210723153838.6785-5-andre.przywara@arm.com (mailing list archive)
State New, archived
Headers show
Series arm64: sunxi: Initial Allwinner H616 SoC support | expand

Commit Message

Andre Przywara July 23, 2021, 3:38 p.m. UTC
Newer versions of the Allwinner RTC, as for instance found in the H616
SoC, no longer store a broken-down day/month/year representation in the
RTC_DAY_REG, but just a linear day number.
The user manual does not give any indication about the expected epoch
time of this day count, but the BSP kernel uses the UNIX epoch, which
allows easy support due to existing conversion functions in the kernel.

Allow tagging a compatible string with a flag, and use that to mark
those new RTCs. Then convert between a UNIX day number (converted into
seconds) and the broken-down day representation using mktime64() and
time64_to_tm() in the set_time/get_time functions.

That enables support for the RTC in those new chips.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 drivers/rtc/rtc-sun6i.c | 66 +++++++++++++++++++++++++++--------------
 1 file changed, 44 insertions(+), 22 deletions(-)

Comments

Jernej Skrabec July 25, 2021, 5:51 a.m. UTC | #1
Hi Andre!

Dne petek, 23. julij 2021 ob 17:38:31 CEST je Andre Przywara napisal(a):
> Newer versions of the Allwinner RTC, as for instance found in the H616
> SoC, no longer store a broken-down day/month/year representation in the
> RTC_DAY_REG, but just a linear day number.
> The user manual does not give any indication about the expected epoch
> time of this day count, but the BSP kernel uses the UNIX epoch, which
> allows easy support due to existing conversion functions in the kernel.
> 
> Allow tagging a compatible string with a flag, and use that to mark
> those new RTCs. Then convert between a UNIX day number (converted into
> seconds) and the broken-down day representation using mktime64() and
> time64_to_tm() in the set_time/get_time functions.
> 
> That enables support for the RTC in those new chips.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  drivers/rtc/rtc-sun6i.c | 66 +++++++++++++++++++++++++++--------------
>  1 file changed, 44 insertions(+), 22 deletions(-)

Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>

Best regards,
Jernej
diff mbox series

Patch

diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
index c551ebf0ac00..a02be8bca6f3 100644
--- a/drivers/rtc/rtc-sun6i.c
+++ b/drivers/rtc/rtc-sun6i.c
@@ -110,6 +110,8 @@ 
 #define SUN6I_YEAR_MIN				1970
 #define SUN6I_YEAR_OFF				(SUN6I_YEAR_MIN - 1900)
 
+#define SECS_PER_DAY				(24 * 3600ULL)
+
 /*
  * There are other differences between models, including:
  *
@@ -133,12 +135,15 @@  struct sun6i_rtc_clk_data {
 	unsigned int has_auto_swt : 1;
 };
 
+#define RTC_LINEAR_DAY	BIT(0)
+
 struct sun6i_rtc_dev {
 	struct rtc_device *rtc;
 	const struct sun6i_rtc_clk_data *data;
 	void __iomem *base;
 	int irq;
 	time64_t alarm;
+	unsigned long flags;
 
 	struct clk_hw hw;
 	struct clk_hw *int_osc;
@@ -467,22 +472,30 @@  static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
 	} while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
 		 (time != readl(chip->base + SUN6I_RTC_HMS)));
 
+	if (chip->flags & RTC_LINEAR_DAY) {
+		/*
+		 * Newer chips store a linear day number, the manual
+		 * does not mandate any epoch base. The BSP driver uses
+		 * the UNIX epoch, let's just copy that, as it's the
+		 * easiest anyway.
+		 */
+		rtc_time64_to_tm((date & 0xffff) * SECS_PER_DAY, rtc_tm);
+	} else {
+		rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
+		rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date) - 1;
+		rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
+
+		/*
+		 * switch from (data_year->min)-relative offset to
+		 * a (1900)-relative one
+		 */
+		rtc_tm->tm_year += SUN6I_YEAR_OFF;
+	}
+
 	rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
 	rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
 	rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
 
-	rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
-	rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date);
-	rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
-
-	rtc_tm->tm_mon  -= 1;
-
-	/*
-	 * switch from (data_year->min)-relative offset to
-	 * a (1900)-relative one
-	 */
-	rtc_tm->tm_year += SUN6I_YEAR_OFF;
-
 	return 0;
 }
 
@@ -567,20 +580,27 @@  static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
 	u32 date = 0;
 	u32 time = 0;
 
-	rtc_tm->tm_year -= SUN6I_YEAR_OFF;
-	rtc_tm->tm_mon += 1;
-
-	date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
-		SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
-		SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
-
-	if (is_leap_year(rtc_tm->tm_year + SUN6I_YEAR_MIN))
-		date |= SUN6I_LEAP_SET_VALUE(1);
-
 	time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
 		SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
 		SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
 
+	if (chip->flags & RTC_LINEAR_DAY) {
+		rtc_tm->tm_sec = 0;
+		rtc_tm->tm_min = 0;
+		rtc_tm->tm_hour = 0;
+		date = div_u64(rtc_tm_to_time64(rtc_tm), SECS_PER_DAY);
+	} else {
+		rtc_tm->tm_year -= SUN6I_YEAR_OFF;
+		rtc_tm->tm_mon += 1;
+
+		date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
+			SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
+			SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
+
+		if (is_leap_year(rtc_tm->tm_year + SUN6I_YEAR_MIN))
+			date |= SUN6I_LEAP_SET_VALUE(1);
+	}
+
 	/* Check whether registers are writable */
 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
 			   SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
@@ -674,6 +694,8 @@  static int sun6i_rtc_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, chip);
 
+	chip->flags = (unsigned long)of_device_get_match_data(&pdev->dev);
+
 	chip->irq = platform_get_irq(pdev, 0);
 	if (chip->irq < 0)
 		return chip->irq;