On 9/24/24 12:08, Macpaul Lin wrote:

On 9/23/24 18:00, AngeloGioacchino Del Regno wrote:

quoted

Add the RTC hardware range parameters to enable the possibility
of using the `start-year` devicetree property which, if present,
will set the start_secs parameter by overriding the defaults
that this driver is setting;

To keep compatibility with (hence have the same date/time reading
as) the old behavior, set:
  - range_min to 1900-01-01 00:00:00
  - range_max to 2027-12-31 23:59:59 (HW year max range is 0-127)
  - start_secs defaulting to 1968-01-02 00:00:00

Please note that the oddness of starting from January 2nd is not
a hardware quirk and it's done only to get the same date/time
reading as an RTC which time was set before this commit.

Also remove the RTC_MIN_YEAR_OFFSET addition and subtraction in
callbacks set_time() and read_time() respectively, as now this
is already done by the API.

Signed-off-by: AngeloGioacchino Del Regno 
[off-list ref]
---
  drivers/rtc/rtc-mt6397.c | 13 ++++---------
  1 file changed, 4 insertions(+), 9 deletions(-)

[snip]

Thanks for helping add new patch fix for RTC.

quoted

@@ -302,6 +293,10 @@ static int mtk_rtc_probe(struct platform_device 

*pdev)
      device_init_wakeup(&pdev->dev, 1);
      rtc->rtc_dev->ops = &mtk_rtc_ops;
+    rtc->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_1900;
+    rtc->rtc_dev->range_max = mktime64(2027, 12, 31, 23, 59, 59);
+    rtc->rtc_dev->start_secs = mktime64(1968, 1, 2, 0, 0, 0);
+    rtc->rtc_dev->set_start_time = true;
      return devm_rtc_register_device(rtc->rtc_dev);
  }

Dear @Zhanhan, Please help to leave comment if you think there is 
something need to be clarify. For example, I've found some relate origin 
defines
in "include/linux/mfd/mt6397/rtc.h"
#define RTC_MIN_YEAR    1968
#define RTC_BASE_YEAR    1900
#define RTC_NUM_YEAR    128
#define RTC_MIN_YEAR_OFFSET    (RTC_MIN_YEAR - RTC_BASE_YEAR)

Should MediaTek remove RTC_MIN_YEAR and RTC_BASE_YEAR in next patch?
And since there may not exist any smartphone/tablet/TV using mt6397
RTC earlier than 2010? Is it possible to change
RTC_TIMESTAMP_BEGIN_1900 to RTC_TIMESTAMP_BEGIN_2000 without breaking
compatibility for these devices?

Thanks
Macpaul Lin

After discussing these change with ZhanZhan, MediaTek think use 
RTC_TIMESTAMP_BEGIN_1900 and the other changes are okay.

Reviewed-by: Macpaul Lin <macpaul.lin@mediatek.com>
Reviewed-by: ZhanZhan Ge <redacted>

Thanks!
Macpaul Lin