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

[Alexandre Belloni <alexandre.belloni@bootlin.com>]

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.


-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com