[PATCH v3 0/3] add support for EXAR XR20M1172 UART

[Konstantin Pugin]

From: Konstantin Pugin <ria.freelander@xxxxxxxxx>

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