[PATCH net-next 3/3] net: stmmac: Add glue layer for Spacemit K3 SoC

[Andrew Lunn]

> +/* Note: the delay step value is at 0.1ps */
> +static const unsigned int k3_delay_step_10x[4] = {
> +	367, 493, 559, 685
> +};

Am i reading it correctly that RGMII delays are limited to these four
values?

If so, please add this list to the DT binding.

> +static int spacemit_dwmac_detected_delay_value(unsigned int delay,
> +					       unsigned int *config)
> +{
> +	int i;
> +	int code, best_code = 0;
> +	unsigned int best_delay = 0;
> +	unsigned int best_config = 0;
> +
> +	if (delay == 0)
> +		return 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(k3_delay_step_10x); i++) {
> +		unsigned int step = k3_delay_step_10x[i];
> +
> +		for (code = 1; code <= MAX_DLINE_DELAY_CODE; code++) {
> +			/*
> +			 * Note K3 require a specific factor for calculate
> +			 * the delay, in this scenario it is 0.9. So the
> +			 * formula is code * step / 10 * 0.9
> +			 */
> +			unsigned int tmp = code * step * 9 / 10 / 10;
> +
> +			if (abs(tmp - delay) < abs(best_delay - delay)) {
> +				best_code = code;
> +				best_delay = tmp;
> +				best_config = i;
> +			}
> +		}
> +	}

With the four values listed in DT, i would make this a straight match,
not the nearest, and return -EINVAL otherwise.

    Andrew