> +	struct i2c_timings i2c_t, *t = &i2c_t;
>  
>  	/* Fall back to previously used values if not supplied */
> -	t->bus_freq_hz = t->bus_freq_hz ?: 100000;
> -	t->scl_fall_ns = t->scl_fall_ns ?: 35;
> -	t->scl_rise_ns = t->scl_rise_ns ?: 200;
> -	t->scl_int_delay_ns = t->scl_int_delay_ns ?: 50;
> +	t->bus_freq_hz = I2C_MAX_STANDARD_MODE_FREQ;
> +	t->scl_fall_ns = 35;
> +	t->scl_rise_ns = 200;
> +	t->scl_int_delay_ns = 50;

Here, the initialization to 0 is missing, so some values are broken.

Why don't we just drop the pointer and init the array directly?

	struct i2c_timings t = {
		.bus_freq_hz = ...
		...
	}