[PATCH 00/13] HID: ft260: add UART and GPIO support, plus I2C fixes

[Michael Zaidman <michael.zaidman@gmail.com>]

Mainline supports only the FT260's I2C bridge. This series adds the
UART/TTY interface and GPIO on top of it, and carries the I2C fixes made
alongside them - two years of out-of-tree work [1], now replayed upstream.

It picks up work that stalled twice: Christina Quast's serial driver,
posted as v4 and v5 and never applied, and my own pre-UART GPIO series
from 2023. Patches 1 and 3 link both threads. This is a new series rather
than a v6, being much more than the serial driver now.

The patches keep the order and the granularity in which the work was
developed, so that authorship stays visible: squashing would fold several
people's changes under one name. The UART and I2C changes also interleave
in the code, so regrouping them by interface would mean a rewrite and a
full retest. Only adjacent commits were squashed. Patch 1 is Christina's,
patch 10 is Rio Liu's.

Tested on a UMFT260EV1A with a 24LC512 EEPROM. I2C - reads and writes
that cross the 60-byte write chunk and the 60/180-byte read chunk caps,
SMBus byte-data and block reads, and the shortened read timeout with the
abort path of patch 13. UART - a 2.8 MB pattern in both directions at
115200 and 1.5 Mbaud against an FT2232 peer, without flow control and
with XON/XOFF and RTS/CTS, plus DTR/RTS toggling over TIOCM*. GPIO -
through libgpiod and legacy sysfs. Every commit builds with W=1, and
checkpatch --strict reports no errors and no warnings across the series.

[1] https://github.com/MichaelZaidman/hid-ft260

Christina Quast (1):
  HID: ft260: add serial driver

Michael Zaidman (11):
  HID: ft260: uart: bring-up fixes
  HID: ft260: add GPIO support on top of UART
  HID: ft260: i2c: reduce driver module loading time
  HID: ft260: i2c: silence sysfs store big-numbers
  HID: ft260: i2c: reduce bus-error message severity
  HID: ft260: uart: enable flow control
  HID: ft260: uart: add modem pins control via ioctl
  HID: ft260: gpio: group sysfs attrs per HID interface
  HID: ft260: i2c: fix large write transaction failure
  HID: ft260: workaround for TN_189 errata endpoint STALL after
    enumeration
  HID: ft260: i2c: abort in-flight transfers with STOP before reset

Rio Liu (1):
  HID: ft260: uart: fix active-low RTS/CTS/DTR/DSR polarity

 drivers/hid/Kconfig     |   10 +-
 drivers/hid/hid-ft260.c | 1967 ++++++++++++++++++++++++++++++++++++---
 2 files changed, 1830 insertions(+), 147 deletions(-)

-- 
2.43.0