[PATCH 1/2] i2c: imx: Don't recover bus when arbitration lost

[Dan Scally]

Hi Frank

On 11/03/2026 15:43, Frank Li wrote:
> On Wed, Mar 11, 2026 at 11:47:43AM +0000, Daniel Scally wrote:
>> The i2c-imx driver runs i2c_recover_bus() if i2c_imx_start() fails.
> 
>> One of the failure modes is an arbitration-lost signal from the
>> hardware however, to which bus recovery is not the right response.
>>
> 
> Supposed
> 
> One of the failure modes is an arbitration-lost signal from the second I2C
> master or slave devices, which is expected behavor. Specially two masters
> try to control the bus simultaneously.
> 
> So bus recovery is not the right response for this case. Add check -EAGAIN
> of i2c_recover_bus() to avoid wrong action.
> 
> Fixed tags here!

Ack - thanks, I'll make the changes for v2.
> 
> Frank
> 
>> Do not try to recover the bus if it loses arbitration during start.
>>
>> Signed-off-by: Daniel Scally <dan.scally at ideasonboard.com>
>> ---
>>   drivers/i2c/busses/i2c-imx.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
>> index 85f554044cf1eec7d28310c3d9e7a7346237afdb..ed2316ab1ba8b6261dabe8af4377136a002e2f0b 100644
>> --- a/drivers/i2c/busses/i2c-imx.c
>> +++ b/drivers/i2c/busses/i2c-imx.c
>> @@ -1539,7 +1539,7 @@ static int i2c_imx_xfer_common(struct i2c_adapter *adapter,
>>
>>   	/* Start I2C transfer */
>>   	result = i2c_imx_start(i2c_imx, atomic);
>> -	if (result) {
>> +	if (result && result != -EAGAIN) {
>>   		/*
>>   		 * Bus recovery uses gpiod_get_value_cansleep() which is not
>>   		 * allowed within atomic context.
>>
>> --
>> 2.43.0
>>