[PATCH v1] i2c: geni: reset controller on NACK to recover from invalid bus state

[Heiko Schocher]

Hello Aswin,

On 02.06.26 08:43, Aswin Murugan wrote:
> During i2c probe, repeated accesses to non-existent slave addresses
> generate consecutive NACK responses. On GENI I2C controllers, these
> back-to-back error conditions leaves the controller in an invalid
> or busy state, especially at lower bus frequencies (100 kHz and
> 400 kHz). As a result, subsequent transfers fails and valid slave
> addresses are not detected.
> 
> Currently, controller recovery is triggered only on timeout errors.
> However, NACK conditions (-EREMOTEIO) can lead to the same stale bus
> state.
> 
> Handle -EREMOTEIO similar to -ETIMEDOUT by issuing a command abort
> before starting the next transfer. This ensures the controller state
> machine is reset and the bus is returned to a known good state.
> 
> This improves reliability of i2c probe and allows correct detection
> of slave devices under repeated probing conditions.
> 
> Signed-off-by: Aswin Murugan <aswin.murugan at oss.qualcomm.com>
> ---
>   drivers/i2c/geni_i2c.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Heiko Schocher <hs at nabladev.com>

bye,
Heiko
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