From: Konstantin Pugin <ria.freelander@gmail.com>

EXAR XR20M1172 UART is mostly SC16IS762-compatible, but
it has additional register which can change UART multiplier
to 4x and 8x, similar to UPF_MAGIC_MULTIPLIER does. So, I used this
flag to guard access to its specific DLD register. It seems than
other EXAR SPI UART modules also have this register, but I tested
only XR20M1172.
Yes, in datasheet this register is called "DLD - Divisor Fractional"
or "DLD - Divisor Fractional Register", calling depends on datasheet
version.

Changes in v2:
  - use full name in git authorship

Changes in v3:
  - change formatting of commit messages to unify width
  - rework commit messages according to code review
  - add XR20M117X namespace for EXAR-specific register
  - do not use UPF_MAGIC_MULTIPLIER for checking EXAR chip,
    use s->devtype directly
  - replace while loop to fls function and expanded check
  - sort compatibles
  - reformat multiline comment.

Konstantin Pugin (3):
  serial: sc16is7xx: announce support of SER_RS485_RTS_ON_SEND
  dt-bindings: sc16is7xx: Add compatible line for XR20M1172 UART
  serial: sc16is7xx: add support for EXAR XR20M1172 UART

 .../bindings/serial/nxp,sc16is7xx.yaml        |  1 +
 drivers/tty/serial/sc16is7xx.c                | 57 +++++++++++++++++--
 2 files changed, 53 insertions(+), 5 deletions(-)

-- 
2.34.1

> From: Konstantin Pugin <rilian.la.te@ya.ru>
> Subject: [PATCH v3 0/3] add support for EXAR XR20M1172 UART

What is the policy in the kernel sources for the name of the manufacturer?
This driver never had special support for the EXAR chips when it was still EXAR.
Since 2017 it is now part of MaxLinear. Should the driver use the name of the
original manufacturer or the name of the manufacturer at the time of addition
to the sources?

Kind regards,
Maarten

On Thu, Apr 18, 2024 at 08:06:04PM +0300, Konstantin Pugin wrote:
> From: Konstantin Pugin <ria.freelander@gmail.com>
> 
> EXAR XR20M1172 UART is mostly SC16IS762-compatible, but
> it has additional register which can change UART multiplier
> to 4x and 8x, similar to UPF_MAGIC_MULTIPLIER does. So, I used this
> flag to guard access to its specific DLD register. It seems than
> other EXAR SPI UART modules also have this register, but I tested
> only XR20M1172.

> Yes, in datasheet this register is called "DLD - Divisor Fractional"
> or "DLD - Divisor Fractional Register", calling depends on datasheet
> version.

I see, interesting inconsistency, but that's what we have to live with.

...

I just have noticed that you haven't used the updated base for your series,
you need to take Greg's KH tty tree and use tty-next / tty-testing branch(es).

Speaking of base, start using --base when preparing patches, it helps CIs to
test against correct branches.

-- 
With Best Regards,
Andy Shevchenko