drivers: net: xgene: fix: Use GPIO to get link status

The link value reported by the link status register is not
reliable when no SPF module inserted. This patchset fixes this
issue by using GPIO to determine the link status.
Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: Quan Nguyen <qnguyen@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/apm/xgene/xgene_enet_main.c

@@ -1381,9 +1381,13 @@ static void xgene_enet_gpiod_get(struct xgene_enet_pdata *pdata)
 {
 	struct device *dev = &pdata->pdev->dev;
 
-	if (pdata->phy_mode != PHY_INTERFACE_MODE_XGMII)
+	pdata->sfp_gpio_en = false;
+	if (pdata->phy_mode != PHY_INTERFACE_MODE_XGMII ||
+	    (!device_property_present(dev, "sfp-gpios") &&
+	     !device_property_present(dev, "rxlos-gpios")))
 		return;
 
+	pdata->sfp_gpio_en = true;
 	pdata->sfp_rdy = gpiod_get(dev, "rxlos", GPIOD_IN);
 	if (IS_ERR(pdata->sfp_rdy))
 		pdata->sfp_rdy = gpiod_get(dev, "sfp", GPIOD_IN);

drivers/net/ethernet/apm/xgene/xgene_enet_main.h

@@ -219,6 +219,7 @@ struct xgene_enet_pdata {
 	u8 rx_delay;
 	bool mdio_driver;
 	struct gpio_desc *sfp_rdy;
+	bool sfp_gpio_en;
 };
 
 struct xgene_indirect_ctl {

drivers/net/ethernet/apm/xgene/xgene_enet_xgmac.c

@@ -415,16 +415,31 @@ static void xgene_enet_clear(struct xgene_enet_pdata *pdata,
 	xgene_enet_wr_ring_if(pdata, addr, data);
 }
 
+static int xgene_enet_gpio_lookup(struct xgene_enet_pdata *pdata)
+{
+	struct device *dev = &pdata->pdev->dev;
+
+	pdata->sfp_rdy = gpiod_get(dev, "rxlos", GPIOD_IN);
+	if (IS_ERR(pdata->sfp_rdy))
+		pdata->sfp_rdy = gpiod_get(dev, "sfp", GPIOD_IN);
+
+	if (IS_ERR(pdata->sfp_rdy))
+		return -ENODEV;
+
+	return 0;
+}
+
 static void xgene_enet_link_state(struct work_struct *work)
 {
 	struct xgene_enet_pdata *pdata = container_of(to_delayed_work(work),
 					 struct xgene_enet_pdata, link_work);
-	struct gpio_desc *sfp_rdy = pdata->sfp_rdy;
 	struct net_device *ndev = pdata->ndev;
 	u32 link_status, poll_interval;
 
 	link_status = xgene_enet_link_status(pdata);
-	if (link_status && !IS_ERR(sfp_rdy) && !gpiod_get_value(sfp_rdy))
+	if (pdata->sfp_gpio_en && link_status &&
+	    (!IS_ERR(pdata->sfp_rdy) || !xgene_enet_gpio_lookup(pdata)) &&
+	    !gpiod_get_value(pdata->sfp_rdy))
 		link_status = 0;
 
 	if (link_status) {