drivers: ethernet: vsc8541: Implement cfg_link function

The cfg_link function was not implemented in this driver, which could
cause the MAC driver to report errors. Add an implementation based on
the phy_mii driver.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>

Author: robhancocksed

drivers/ethernet/phy/phy_microchip_vsc8541.c

@@ -15,6 +15,7 @@ LOG_MODULE_REGISTER(microchip_vsc8541, CONFIG_PHY_LOG_LEVEL);
 #include <string.h>
 #include <zephyr/sys/util_macro.h>
 #include <zephyr/drivers/gpio.h>
+#include "phy_mii.h"
 
 /* phy page selectors */
 #define PHY_PAGE_0 0x00 /* main registers space active */
@@ -404,6 +405,31 @@ static int phy_mc_vsc8541_get_link(const struct device *dev, struct phy_link_sta
 	return 0;
 }
 
+/**
+ * @brief Reconfigure the link speed
+ *
+ * @param dev device structure to phy
+ * @param adv_speeds speeds to be advertised
+ * @param flags configuration flags
+ */
+static int phy_mc_vsc8541_cfg_link(const struct device *dev, enum phy_link_speed adv_speeds,
+				   enum phy_cfg_link_flag flags)
+{
+	int ret = 0;
+
+	if ((flags & PHY_FLAG_AUTO_NEGOTIATION_DISABLED) != 0U) {
+		ret = phy_mii_set_bmcr_reg_autoneg_disabled(dev, adv_speeds);
+	} else {
+		ret = phy_mii_cfg_link_autoneg(dev, adv_speeds, true);
+	}
+
+	if (ret == -EALREADY) {
+		LOG_DBG("Link already configured");
+	}
+
+	return 0;
+}
+
 /**
  * @brief Set callback which is used to announce link status changes
  *
@@ -559,6 +585,7 @@ static int phy_mc_vsc8541_write_ext(const struct device *dev, uint16_t reg_addr,
 
 static DEVICE_API(ethphy, mc_vsc8541_phy_api) = {
 	.get_link = phy_mc_vsc8541_get_link,
+	.cfg_link = phy_mc_vsc8541_cfg_link,
 	.link_cb_set = phy_mc_vsc8541_link_cb_set,
 	.read = phy_mc_vsc8541_read_ext,
 	.write = phy_mc_vsc8541_write_ext,