> @@ -97,59 +98,83 @@ static const struct chip_desc chips[] = {
>  		.nchans = 2,
>  		.enable = 0x4,
>  		.muxtype = pca954x_ismux,
> +		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },

Can't we just leave this empty and add a NULL pointer check below when
testing for the device id?