On Mon, Sep 20, 2021 at 11:52:09AM +0200, Horatiu Vultur wrote:

+static int lan966x_calc_sd6g40_setup_lane(struct lan966x_sd6g40_setup_args config,
+					  struct lan966x_sd6g40_setup *ret_val)
+{
+	struct lan966x_sd6g40_mode_args sd6g40_mode;
+	struct lan966x_sd6g40_mode_args *mode_args = &sd6g40_mode;
+
+	if (lan966x_sd6g40_get_conf_from_mode(config.mode, config.refclk125M,
+					      mode_args))
+		return -1;

This needs fixing to be a real negative error number.
lan966x_sd6g40_setup_lane() propagates this functions non-zero
return value, which is then propagated through lan966x_sd6g40_setup(),
and then through serdes_set_mode() to the PHY layer.

In general, I would suggest that _all_ int-returning functions in the
kernel that return a negative failure value _should_ _always_ return a
negative error code, so that your reviewers don't have to chase code
paths to work out whether a mistake such as the above exists.

To put it another way: never use "return -1" in the kernel.

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