net: ethernet: renesas: rcar_gen4_ptp: Fail on unknown register layout

Instead of printing a warning and proceeding with an unknown register
layout return an error. The only call site is already prepared to
propagate the error.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/renesas/rcar_gen4_ptp.c

@@ -130,23 +130,30 @@ static struct ptp_clock_info rcar_gen4_ptp_info = {
 	.enable = rcar_gen4_ptp_enable,
 };
 
-static void rcar_gen4_ptp_set_offs(struct rcar_gen4_ptp_private *ptp_priv,
-				   enum rcar_gen4_ptp_reg_layout layout)
+static int rcar_gen4_ptp_set_offs(struct rcar_gen4_ptp_private *ptp_priv,
+				  enum rcar_gen4_ptp_reg_layout layout)
 {
-	WARN_ON(layout != RCAR_GEN4_PTP_REG_LAYOUT_S4);
+	if (layout != RCAR_GEN4_PTP_REG_LAYOUT_S4)
+		return -EINVAL;
 
 	ptp_priv->offs = &s4_offs;
+
+	return 0;
 }
 
 int rcar_gen4_ptp_register(struct rcar_gen4_ptp_private *ptp_priv,
 			   enum rcar_gen4_ptp_reg_layout layout, u32 clock)
 {
+	int ret;
+
 	if (ptp_priv->initialized)
 		return 0;
 
 	spin_lock_init(&ptp_priv->lock);
 
-	rcar_gen4_ptp_set_offs(ptp_priv, layout);
+	ret = rcar_gen4_ptp_set_offs(ptp_priv, layout);
+	if (ret)
+		return ret;
 
 	ptp_priv->default_addend = clock;
 	iowrite32(ptp_priv->default_addend, ptp_priv->addr + ptp_priv->offs->increment);