Re: [PATCH] platform/mellanox: Fix logic error in power state check in mlxreg-lc

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

On Mon, 30 Jun 2025, Alok Tiwari wrote:

> Fixes a logic issue in mlxreg_lc_completion_notify() where the
> intention was to check if MLXREG_LC_POWERED flag is not set before
> powering on the device.
> 
> The original code used "state & ~MLXREG_LC_POWERED" to check for the
> absence of the POWERED bit. However this condition evaluates to true
> even when other bits are set, leading to potentially incorrect
> behavior.
> 
> Corrected the logic to explicitly check for the absence of
> MLXREG_LC_POWERED using !(state & MLXREG_LC_POWERED).
> 
> Suggested-by: Vadim Pasternak <vadimp@nvidia.com>
> Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>

Makes sense but please add Fixes tag and resubmit as v2.

> ---
>  drivers/platform/mellanox/mlxreg-lc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/mellanox/mlxreg-lc.c b/drivers/platform/mellanox/mlxreg-lc.c
> index aee395bb48ae4..8681ceb7144ba 100644
> --- a/drivers/platform/mellanox/mlxreg-lc.c
> +++ b/drivers/platform/mellanox/mlxreg-lc.c
> @@ -688,7 +688,7 @@ static int mlxreg_lc_completion_notify(void *handle, struct i2c_adapter *parent,
>  	if (regval & mlxreg_lc->data->mask) {
>  		mlxreg_lc->state |= MLXREG_LC_SYNCED;
>  		mlxreg_lc_state_update_locked(mlxreg_lc, MLXREG_LC_SYNCED, 1);
> -		if (mlxreg_lc->state & ~MLXREG_LC_POWERED) {
> +		if (!(mlxreg_lc->state & MLXREG_LC_POWERED)) {
>  			err = mlxreg_lc_power_on_off(mlxreg_lc, 1);
>  			if (err)
>  				goto mlxreg_lc_regmap_power_on_off_fail;
> 

-- 
 i.