Subject: Re: [PATCH v10 1/3] net: ethernet: mtk_eth_soc: fix return value and refactor MDIO ops

From: Andrew Lunn <[email-masked]>
Date: Sun, 2 Jan 2022 17:43:32 +0100

> +static int _mtk_mdio_write(struct mtk_eth *eth, u32 phy_addr, u32 phy_reg,
> +			   u32 write_data)
>  {
>  	if (mtk_mdio_busy_wait(eth))
> -		return -1;
> -
> -	write_data &= 0xffff;
> +		return -EBUSY;

-ETIMEDOUT would be more normal.

I would probably also change mtk_mdio_busy_wait() so that it either
returned 0, or -ETIMEDOUT. That is the general pattern in Linux,
return 0 on success, or a negative error code. Returning -1 is an
invitation for trouble.

The code would then become

    ret = mtk_mdio_busy_wait(eth);
    if (ret < 0)
       return ret;

which is a very common pattern in Linux.

      Andrew