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i2c: core: support recovery for single-ended GPIOs

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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@nokia.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260511113726.49041-3-jie.i.li@nokia.com
This commit is contained in:
Jie Li 2026-05-11 13:37:26 +02:00 committed by Andi Shyti
parent 87e713f200
commit 18ca2ce160
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1 changed files with 2 additions and 1 deletions
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3
drivers/i2c/i2c-core-base.c
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@ -446,7 +446,8 @@ 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;
if (gpiod_get_direction(bri->sda_gpiod) == GPIO_LINE_DIRECTION_OUT)
if (gpiod_get_direction(bri->sda_gpiod) == GPIO_LINE_DIRECTION_OUT ||
gpiod_is_single_ended(bri->sda_gpiod))
bri->set_sda = set_sda_gpio_value;
}
} else if (bri->recover_bus == i2c_generic_scl_recovery) {