Re: [PATCH v5 2/2] i2c: core: support recovery for single-ended GPIOs

Hi Jie,

On Mon, May 11, 2026 at 01:37:26PM +0200, Jie Li wrote:
> Currently, i2c_init_recovery() only assigns the set_sda/set_scl
> hooks if gpiod_get_direction() returns GPIO_LINE_DIRECTION_OUT.
> 
> This logic fails on certain SoC controllers where open-drain lines
> in a high-impedance state are physically reported as inputs. This
> leads to a "deadlock" where the I2C core refuses to assign the
> recovery hooks because it incorrectly assumes the pins are
> input-only, even though they are fully capable of driving the bus
> low for recovery.
> 
> Update the recovery initialization to use the new
> gpiod_is_single_ended() helper. If a GPIO is configured as
> open-drain or open-source in the firmware, it is safe to assume
> it can be used for bus recovery, even if the current hardware
> direction is reported as input.
> 
> Signed-off-by: Jie Li <[email protected]>
> Reviewed-by: Linus Walleij <[email protected]>
> Acked-by: Wolfram Sang <[email protected]>

Please do not send subsequent versions as --in-reply-to, it's
difficult to track them.

> ---
>  drivers/i2c/i2c-core-base.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 9c46147e3506..a3c33e804d47 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -445,8 +445,8 @@ static int i2c_init_recovery(struct i2c_adapter *adap)
>  		bri->set_scl = set_scl_gpio_value;
>  		if (bri->sda_gpiod) {
>  			bri->get_sda = get_sda_gpio_value;
> -			/* FIXME: add proper flag instead of '0' once available */
> -			if (gpiod_get_direction(bri->sda_gpiod) == 0)
> +			if (gpiod_get_direction(bri->sda_gpiod) == GPIO_LINE_DIRECTION_OUT ||
> +			    gpiod_is_single_ended(bri->sda_gpiod))

there was a little conflict here which I fixes and merged to
i2c/i2c.

Thanks,
Andi