[PATCH v4 0/2] i2c: improve bus recovery for single-ended GPIOs

[Jie Li <lj29312931@gmail.com>]

Greetings,

This series addresses a limitation in the I2C bus recovery mechanism
where certain open-drain GPIOs are incorrectly identified as
input-only, preventing the recovery logic from functioning.

Following the suggestion from Linus Walleij, this version drops the
previously proposed "force-set-sda" DT property. Instead, it
introduces a generic helper in the GPIO subsystem to identify
single-ended configurations. This allows the I2C core to reliably
enable recovery for open-drain lines regardless of the
instantaneous hardware direction reporting.

As suggested by Wolfram, this series should go via the GPIO tree,
since patch 2/2 depends on the new gpiolib helper introduced in
patch 1/2.

Changes in v4:
- Patch 2:
  - Use GPIO_LINE_DIRECTION_OUT instead of the literal '0' when
    checking the return value of gpiod_get_direction(), and drop
    the now-obsolete FIXME comment (suggested by Wolfram Sang).
  - Added Acked-by: Wolfram Sang.

Changes in v3:
- Patch 1:
  - Changed return type of gpiod_is_single_ended() from int to bool.
  - Updated return values from 0/1 to false/true.
  - Added Reviewed-by: Linus Walleij.
- Patch 2:
  - Added Reviewed-by: Linus Walleij.

Changes in v2:
- Replaced DT-based "force-set-sda" with a gpiolib helper.
- Added gpiod_is_single_ended() to drivers/gpio/gpiolib.c.
- Updated i2c-core-base.c to use the new helper.

Jie Li (2):
  gpiolib: add gpiod_is_single_ended() helper
  i2c: core: support recovery for single-ended GPIOs

 drivers/gpio/gpiolib.c        | 22 ++++++++++++++++++++++
 drivers/i2c/i2c-core-base.c   |  4 ++--
 include/linux/gpio/consumer.h |  5 +++++
 3 files changed, 29 insertions(+), 2 deletions(-)

-- 
2.43.0