[PATCH v6 0/4] add driver for the WCH CH341 in I2C/GPIO mode

[frank zago <frank@xxxxxxxx>]

The CH341 is a multifunction chip, presenting 3 different USB PID. One
of these functions is for I2C/SPI/GPIO. This new set of drivers will
manage I2C and GPIO.

Changes from v5:
Addressed reviewers' comments.
Better handling of 0-bytes i2c commands
Use of better USB API.

Changes from v4:
I should have addressed all the comments: rework of the GPIO interrupt
handling code to be more modern, changes in Kconfig wording, some code
cleanup.
Driver was tested again with up to 4 of these devices. No
error seen.

Changes from v3:
  - really converted to an MFD driver. Driver is now split into 3
    modules (MFD+I2C+GPIO).
  - minor code cleanups

Changes from v2:
  - bug fixes
  - more robust USB enumeration
  - Changed to an MFD driver as suggested

During testing I found that i2c handles hot removal, but not gpio. The
gpio subsystem will complain with 'REMOVING GPIOCHIP WITH GPIOS STILL
REQUESTED', but it's a gpiolib issue.

Changes from v1:
  - Removed double Signed-off-by
  - Move Kconfig into the same directory as the driver

frank zago (4):
  mfd: ch341: add core driver for the WCH CH341 in I2C/SPI/GPIO mode
  gpio: ch341: add GPIO MFD cell driver for the CH341
  i2c: ch341: add I2C MFD cell driver for the CH341
  docs: misc: add documentation for ch341 driver

 Documentation/misc-devices/ch341.rst | 109 ++++++++
 Documentation/misc-devices/index.rst |   1 +
 MAINTAINERS                          |   9 +
 drivers/gpio/Kconfig                 |  10 +
 drivers/gpio/Makefile                |   1 +
 drivers/gpio/gpio-ch341.c            | 385 +++++++++++++++++++++++++++
 drivers/i2c/busses/Kconfig           |  10 +
 drivers/i2c/busses/Makefile          |   1 +
 drivers/i2c/busses/i2c-ch341.c       | 377 ++++++++++++++++++++++++++
 drivers/mfd/Kconfig                  |  10 +
 drivers/mfd/Makefile                 |   1 +
 drivers/mfd/ch341-core.c             |  90 +++++++
 include/linux/mfd/ch341.h            |  26 ++
 13 files changed, 1030 insertions(+)
 create mode 100644 Documentation/misc-devices/ch341.rst
 create mode 100644 drivers/gpio/gpio-ch341.c
 create mode 100644 drivers/i2c/busses/i2c-ch341.c
 create mode 100644 drivers/mfd/ch341-core.c
 create mode 100644 include/linux/mfd/ch341.h

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2.32.0