Re: [PATCH v3] rtc: ds1307: Add driver for Epson RX8901CE

[Fredrik M Olsson <fredriol@axis.com>]

On 10/19/26 22:34, Alexandre Belloni wrote:
> Hello,
> 
> On 16/10/2026 09:41:14+0200, Fredrik M Olsson wrote:
>> On 6/29/26 17:13, Fredrik M Olsson wrote:
>>> Adds support for:
>>> - Reading and writing time to/from the RTC.
>>> - Changing Backup Switch Mode (BSM) to DISABLED/DIRECT/LEVEL using the
>>>     RTC_PARAM_SET ioctl.
>>> - Optionally enabling battery charging.
>>> - Reading the battery voltage low status using the RTC_VL_READ ioctl
>>>     (only supported in LEVEL BSM), which also reports invalid time
>>>     information if the VLF flag is set.
>>>
>>> Signed-off-by: Fredrik M Olsson<fredrik.m.olsson@axis.com>
>>> ---
>>> Add basic support for the Epson RX8901CE RTC.
>>> Datasheet:https://download.epsondevice.com/td/pdf/app/RX8901CE_en.pdf
>>>
>>> Also includes a bug fix for an issue with reading the weekday from the
>>> RTC which affects both the existing rx8130 and this rx8901 driver.
>>> ---
>>> Changes in v3:
>>> - Clear CHGEN when trickle battery charging is disabled.
>>> - Link to v2:https://lore.kernel.org/r/20260520-ds1307-rx8901-add-v2-0-
>>> e069ea32e1db@axis.com
>>>
>>> Changes in v2:
>>> - Squashed the Voltage Low status patch into the driver patch
>>> - Switch from dev_err to dev_dbg
>>> - Implement Backup Switch Mode (BSM) ioctl instead of hard coding
>>>     switching mode.
>>> - Change the prototype for the do_trickle_setup function pointer in
>>>     order to make it possible to propagate error codes from the added
>>>     PWSW_CFG register read operation. This read operation is added so not
>>>     to override previously set register fields.
>>> - Link to v1:https://lore.kernel.org/r/20251219-ds1307-rx8901-add-v1-0-
>>> b13f346ebe93@axis.com
>>
>> [...]
>>
>> Friendly ping.
> 
> This was dropped from the queue because kbuild reported warnings and
> smatch issues on the patch.
> 
> Also, I feel like this should actually be a separate driver instead of
> growing ds1307 larger than it already is.
> 
> 
Thanks for the feedback.

I will look into the kbuild warnings and smatch issues.

Could you clarify what you have in mind for a separate RX8901 driver, 
and what the main concern you have with adding RX8901 support to ds1307? 
Is the concern mainly with the changes made to support BSM handling?


-- 
/Fredrik