net: stmmac: Enable stmmac main clock when probing hardware

The stmmac driver does not enable the main clock during the probe phase.
If the clock was not enabled by the boot loader or was disabled by the
kernel, hardware features and the MDIO bus would not be probed properly.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -1680,8 +1680,6 @@ static int stmmac_open(struct net_device *dev)
 	struct stmmac_priv *priv = netdev_priv(dev);
 	int ret;
 
-	clk_prepare_enable(priv->stmmac_clk);
-
 	stmmac_check_ether_addr(priv);
 
 	if (priv->pcs != STMMAC_PCS_RGMII && priv->pcs != STMMAC_PCS_TBI &&
@@ -1819,7 +1817,6 @@ static int stmmac_release(struct net_device *dev)
 #ifdef CONFIG_STMMAC_DEBUG_FS
 	stmmac_exit_fs();
 #endif
-	clk_disable_unprepare(priv->stmmac_clk);
 
 	stmmac_release_ptp(priv);
 
@@ -2727,10 +2724,18 @@ struct stmmac_priv *stmmac_dvr_probe(struct device *device,
 	if ((phyaddr >= 0) && (phyaddr <= 31))
 		priv->plat->phy_addr = phyaddr;
 
+	priv->stmmac_clk = devm_clk_get(priv->device, STMMAC_RESOURCE_NAME);
+	if (IS_ERR(priv->stmmac_clk)) {
+		dev_warn(priv->device, "%s: warning: cannot get CSR clock\n",
+			 __func__);
+		goto error_clk_get;
+	}
+	clk_prepare_enable(priv->stmmac_clk);
+
 	/* Init MAC and get the capabilities */
 	ret = stmmac_hw_init(priv);
 	if (ret)
-		goto error_free_netdev;
+		goto error_hw_init;
 
 	ndev->netdev_ops = &stmmac_netdev_ops;
 
@@ -2768,12 +2773,6 @@ struct stmmac_priv *stmmac_dvr_probe(struct device *device,
 		goto error_netdev_register;
 	}
 
-	priv->stmmac_clk = clk_get(priv->device, STMMAC_RESOURCE_NAME);
-	if (IS_ERR(priv->stmmac_clk)) {
-		pr_warn("%s: warning: cannot get CSR clock\n", __func__);
-		goto error_clk_get;
-	}
-
 	/* If a specific clk_csr value is passed from the platform
 	 * this means that the CSR Clock Range selection cannot be
 	 * changed at run-time and it is fixed. Viceversa the driver'll try to
@@ -2801,12 +2800,12 @@ struct stmmac_priv *stmmac_dvr_probe(struct device *device,
 	return priv;
 
 error_mdio_register:
-	clk_put(priv->stmmac_clk);
-error_clk_get:
 	unregister_netdev(ndev);
 error_netdev_register:
 	netif_napi_del(&priv->napi);
-error_free_netdev:
+error_hw_init:
+	clk_disable_unprepare(priv->stmmac_clk);
+error_clk_get:
 	free_netdev(ndev);
 
 	return NULL;
@@ -2833,6 +2832,7 @@ int stmmac_dvr_remove(struct net_device *ndev)
 		stmmac_mdio_unregister(ndev);
 	netif_carrier_off(ndev);
 	unregister_netdev(ndev);
+	clk_disable_unprepare(priv->stmmac_clk);
 	free_netdev(ndev);
 
 	return 0;