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

[Jie I. Li (Nokia)]

Hi Andi,

Thank you very much for resolving the conflict and merging the patch! 

This is my first time contributing code to the Linux community, and seeing it finally merged means a lot to me. I truly appreciate your patience, help, and time in guiding me through this.

I will also keep the --in-reply-to note in mind for future submissions.

Best regards,
Jie Li


-----Original Message-----
From: Andi Shyti <andi.shyti@xxxxxxxxxx> 
Sent: Wednesday, July 29, 2026 11:47 PM
To: Jie Li <lj29312931@xxxxxxxxx>
Cc: Bartosz Golaszewski <brgl@xxxxxxxxxx>; Linus Walleij <linusw@xxxxxxxxxx>; Wolfram Sang <wsa@xxxxxxxxxx>; Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>; linux-gpio@xxxxxxxxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Jie I. Li (Nokia) <jie.i.li@xxxxxxxxx>
Subject: Re: [PATCH v5 2/2] i2c: core: support recovery for single-ended GPIOs

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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 <jie.i.li@xxxxxxxxx>
> Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>
> Acked-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>

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