net: fec: optimize the clock management to save power

Add below clock management to save fec power:
- After probe, disable all clocks incluing ipg, ahb, enet_out, ptp clock.
- Open ethx interface enable necessary clocks.
  Close ethx interface disable all clocks.

The patch also encapsulates the all enet clocks enable/disable to
.fec_enet_clk_enable(), which can reduce the repetitional code in
driver.

Signed-off-by: Fugang Duan <B38611@freescale.com>
Acked-by: Frank Li <Frank.li@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fec_main.c

@@ -1255,6 +1255,49 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 	return 0;
 }
 
+static int fec_enet_clk_enable(struct net_device *ndev, bool enable)
+{
+	struct fec_enet_private *fep = netdev_priv(ndev);
+	int ret;
+
+	if (enable) {
+		ret = clk_prepare_enable(fep->clk_ahb);
+		if (ret)
+			return ret;
+		ret = clk_prepare_enable(fep->clk_ipg);
+		if (ret)
+			goto failed_clk_ipg;
+		if (fep->clk_enet_out) {
+			ret = clk_prepare_enable(fep->clk_enet_out);
+			if (ret)
+				goto failed_clk_enet_out;
+		}
+		if (fep->clk_ptp) {
+			ret = clk_prepare_enable(fep->clk_ptp);
+			if (ret)
+				goto failed_clk_ptp;
+		}
+	} else {
+		clk_disable_unprepare(fep->clk_ahb);
+		clk_disable_unprepare(fep->clk_ipg);
+		if (fep->clk_enet_out)
+			clk_disable_unprepare(fep->clk_enet_out);
+		if (fep->clk_ptp)
+			clk_disable_unprepare(fep->clk_ptp);
+	}
+
+	return 0;
+failed_clk_ptp:
+	if (fep->clk_enet_out)
+		clk_disable_unprepare(fep->clk_enet_out);
+failed_clk_enet_out:
+		clk_disable_unprepare(fep->clk_ipg);
+failed_clk_ipg:
+		clk_disable_unprepare(fep->clk_ahb);
+
+	return ret;
+}
+
 static int fec_enet_mii_probe(struct net_device *ndev)
 {
 	struct fec_enet_private *fep = netdev_priv(ndev);
@@ -1773,6 +1816,10 @@ fec_enet_open(struct net_device *ndev)
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	int ret;
 
+	ret = fec_enet_clk_enable(ndev, true);
+	if (ret)
+		return ret;
+
 	/* I should reset the ring buffers here, but I don't yet know
 	 * a simple way to do that.
 	 */
@@ -1811,6 +1858,7 @@ fec_enet_close(struct net_device *ndev)
 		phy_disconnect(fep->phy_dev);
 	}
 
+	fec_enet_clk_enable(ndev, false);
 	fec_enet_free_buffers(ndev);
 
 	return 0;
@@ -2164,26 +2212,10 @@ fec_probe(struct platform_device *pdev)
 		fep->bufdesc_ex = 0;
 	}
 
-	ret = clk_prepare_enable(fep->clk_ahb);
+	ret = fec_enet_clk_enable(ndev, true);
 	if (ret)
 		goto failed_clk;
 
-	ret = clk_prepare_enable(fep->clk_ipg);
-	if (ret)
-		goto failed_clk_ipg;
-
-	if (fep->clk_enet_out) {
-		ret = clk_prepare_enable(fep->clk_enet_out);
-		if (ret)
-			goto failed_clk_enet_out;
-	}
-
-	if (fep->clk_ptp) {
-		ret = clk_prepare_enable(fep->clk_ptp);
-		if (ret)
-			goto failed_clk_ptp;
-	}
-
 	fep->reg_phy = devm_regulator_get(&pdev->dev, "phy");
 	if (!IS_ERR(fep->reg_phy)) {
 		ret = regulator_enable(fep->reg_phy);
@@ -2225,6 +2257,7 @@ fec_probe(struct platform_device *pdev)
 
 	/* Carrier starts down, phylib will bring it up */
 	netif_carrier_off(ndev);
+	fec_enet_clk_enable(ndev, false);
 
 	ret = register_netdev(ndev);
 	if (ret)
@@ -2244,15 +2277,7 @@ fec_probe(struct platform_device *pdev)
 	if (fep->reg_phy)
 		regulator_disable(fep->reg_phy);
 failed_regulator:
-	if (fep->clk_ptp)
+	fec_enet_clk_enable(ndev, false);
-		clk_disable_unprepare(fep->clk_ptp);
-failed_clk_ptp:
-	if (fep->clk_enet_out)
-		clk_disable_unprepare(fep->clk_enet_out);
-failed_clk_enet_out:
-	clk_disable_unprepare(fep->clk_ipg);
-failed_clk_ipg:
-	clk_disable_unprepare(fep->clk_ahb);
 failed_clk:
 failed_ioremap:
 	free_netdev(ndev);
@@ -2272,14 +2297,9 @@ fec_drv_remove(struct platform_device *pdev)
 	del_timer_sync(&fep->time_keep);
 	if (fep->reg_phy)
 		regulator_disable(fep->reg_phy);
-	if (fep->clk_ptp)
-		clk_disable_unprepare(fep->clk_ptp);
 	if (fep->ptp_clock)
 		ptp_clock_unregister(fep->ptp_clock);
-	if (fep->clk_enet_out)
+	fec_enet_clk_enable(ndev, false);
-		clk_disable_unprepare(fep->clk_enet_out);
-	clk_disable_unprepare(fep->clk_ipg);
-	clk_disable_unprepare(fep->clk_ahb);
 	free_netdev(ndev);
 
 	return 0;
@@ -2296,12 +2316,7 @@ fec_suspend(struct device *dev)
 		fec_stop(ndev);
 		netif_device_detach(ndev);
 	}
-	if (fep->clk_ptp)
+	fec_enet_clk_enable(ndev, false);
-		clk_disable_unprepare(fep->clk_ptp);
-	if (fep->clk_enet_out)
-		clk_disable_unprepare(fep->clk_enet_out);
-	clk_disable_unprepare(fep->clk_ipg);
-	clk_disable_unprepare(fep->clk_ahb);
 
 	if (fep->reg_phy)
 		regulator_disable(fep->reg_phy);
@@ -2322,25 +2337,9 @@ fec_resume(struct device *dev)
 			return ret;
 	}
 
-	ret = clk_prepare_enable(fep->clk_ahb);
+	ret = fec_enet_clk_enable(ndev, true);
 	if (ret)
-		goto failed_clk_ahb;
+		goto failed_clk;
-
-	ret = clk_prepare_enable(fep->clk_ipg);
-	if (ret)
-		goto failed_clk_ipg;
-
-	if (fep->clk_enet_out) {
-		ret = clk_prepare_enable(fep->clk_enet_out);
-		if (ret)
-			goto failed_clk_enet_out;
-	}
-
-	if (fep->clk_ptp) {
-		ret = clk_prepare_enable(fep->clk_ptp);
-		if (ret)
-			goto failed_clk_ptp;
-	}
 
 	if (netif_running(ndev)) {
 		fec_restart(ndev, fep->full_duplex);
@@ -2349,14 +2348,7 @@ fec_resume(struct device *dev)
 
 	return 0;
 
-failed_clk_ptp:
+failed_clk:
-	if (fep->clk_enet_out)
-		clk_disable_unprepare(fep->clk_enet_out);
-failed_clk_enet_out:
-	clk_disable_unprepare(fep->clk_ipg);
-failed_clk_ipg:
-	clk_disable_unprepare(fep->clk_ahb);
-failed_clk_ahb:
 	if (fep->reg_phy)
 		regulator_disable(fep->reg_phy);
 	return ret;