Re: [PATCH v3 4/5] rtc: mt6397: Remove start time parameters

AngeloGioacchino Del Regno
2025-04-14T11:09:17Z

Il 11/04/25 15:39, Alexandre Belloni ha scritto:
> On 11/04/2025 15:36:12+0200, Alexandre Belloni wrote:
>> On 11/04/2025 14:35:57+0200, Alexandre Mergnat wrote:
>>> The start time parameters is currently hardcoded to the driver, but
>>> it may not fit with all equivalent RTC that driver is able to support.
>>>
>>> Remove the start_secs and set_start_time value setup because it
>>> will be handled by the rtc_device_get_offset function using the
>>> start-year DTS property.
>>>
>>> Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
>>> ---
>>> drivers/rtc/rtc-mt6397.c | 2 --
>>> 1 file changed, 2 deletions(-)
>>>
>>> diff --git a/drivers/rtc/rtc-mt6397.c b/drivers/rtc/rtc-mt6397.c
>>> index 692c00ff544b2..d47626d47602f 100644
>>> --- a/drivers/rtc/rtc-mt6397.c
>>> +++ b/drivers/rtc/rtc-mt6397.c
>>> @@ -291,8 +291,6 @@ static int mtk_rtc_probe(struct platform_device *pdev)
>>> 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;
>>>
>>
>> This is going to break the time for people upgrading their kernel, you
>> are unfortunately stuck with this.
>>
>
> To be clear, the breakage will happen when upgrading the kernel but not
> the device tree with 5/5
>

Yes, you're stuck with this. Devicetree has to be retrocompatible.

Besides, this start_secs is what gets used by default, and the start-year
devicetree property should take precedence and effectively override the
start_secs default.

Just keep it there.... :-)

Cheers,
Angelo

>>> return devm_rtc_register_device(rtc->rtc_dev);
>>> }
>>>
>>> --
>>> 2.25.1
>>>
>>
>> --
>> Alexandre Belloni, co-owner and COO, Bootlin
>> Embedded Linux and Kernel engineering
>> https://bootlin.com
>