net: ethernet: macb: Add support for rx_clk

Some of the platforms like zynqmp ultrascale+ has a
separate clock gate for the rx clock. Add an optional
rx_clk so that the clock can be enabled.

Signed-off-by: Shubhrajyoti Datta <[e-mail]>
Acked-by: Nicolas Ferre <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/devicetree/bindings/net/macb.txt

···
 - clock-names: Tuple listing input clock names.
 	Required elements: 'pclk', 'hclk'
 	Optional elements: 'tx_clk'
+	Optional elements: 'rx_clk' applies to cdns,zynqmp-gem
 - clocks: Phandles to input clocks.
 
 Optional properties for PHY child node:

drivers/net/ethernet/cadence/macb.c

···
 }
 
 static int macb_clk_init(struct platform_device *pdev, struct clk **pclk,
-			 struct clk **hclk, struct clk **tx_clk)
+			 struct clk **hclk, struct clk **tx_clk,
+			 struct clk **rx_clk)
 {
 	int err;
 
···
 	if (IS_ERR(*tx_clk))
 		*tx_clk = NULL;
 
+	*rx_clk = devm_clk_get(&pdev->dev, "rx_clk");
+	if (IS_ERR(*rx_clk))
+		*rx_clk = NULL;
+
 	err = clk_prepare_enable(*pclk);
 	if (err) {
 		dev_err(&pdev->dev, "failed to enable pclk (%u)\n", err);
···
 		goto err_disable_hclk;
 	}
 
+	err = clk_prepare_enable(*rx_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable rx_clk (%u)\n", err);
+		goto err_disable_txclk;
+	}
+
 	return 0;
+
+err_disable_txclk:
+	clk_disable_unprepare(*tx_clk);
 
 err_disable_hclk:
 	clk_disable_unprepare(*hclk);
···
 };
 
 static int at91ether_clk_init(struct platform_device *pdev, struct clk **pclk,
-			      struct clk **hclk, struct clk **tx_clk)
+			      struct clk **hclk, struct clk **tx_clk,
+			      struct clk **rx_clk)
 {
 	int err;
 
 	*hclk = NULL;
 	*tx_clk = NULL;
+	*rx_clk = NULL;
 
 	*pclk = devm_clk_get(&pdev->dev, "ether_clk");
 	if (IS_ERR(*pclk))
···
 static int macb_probe(struct platform_device *pdev)
 {
 	int (*clk_init)(struct platform_device *, struct clk **,
-			struct clk **, struct clk **)
+			struct clk **, struct clk **,  struct clk **)
 					      = macb_clk_init;
 	int (*init)(struct platform_device *) = macb_init;
 	struct device_node *np = pdev->dev.of_node;
 	struct device_node *phy_node;
 	const struct macb_config *macb_config = NULL;
-	struct clk *pclk, *hclk = NULL, *tx_clk = NULL;
+	struct clk *pclk, *hclk = NULL, *tx_clk = NULL, *rx_clk = NULL;
 	unsigned int queue_mask, num_queues;
 	struct macb_platform_data *pdata;
 	bool native_io;
···
 		}
 	}
 
-	err = clk_init(pdev, &pclk, &hclk, &tx_clk);
+	err = clk_init(pdev, &pclk, &hclk, &tx_clk, &rx_clk);
 	if (err)
 		return err;
 
···
 	bp->pclk = pclk;
 	bp->hclk = hclk;
 	bp->tx_clk = tx_clk;
+	bp->rx_clk = rx_clk;
 	if (macb_config)
 		bp->jumbo_max_len = macb_config->jumbo_max_len;
 
···
 	clk_disable_unprepare(tx_clk);
 	clk_disable_unprepare(hclk);
 	clk_disable_unprepare(pclk);
+	clk_disable_unprepare(rx_clk);
 
 	return err;
 }
···
 		clk_disable_unprepare(bp->tx_clk);
 		clk_disable_unprepare(bp->hclk);
 		clk_disable_unprepare(bp->pclk);
+		clk_disable_unprepare(bp->rx_clk);
 		free_netdev(dev);
 	}
 
···
 		clk_disable_unprepare(bp->tx_clk);
 		clk_disable_unprepare(bp->hclk);
 		clk_disable_unprepare(bp->pclk);
+		clk_disable_unprepare(bp->rx_clk);
 	}
 
 	return 0;
···
 		clk_prepare_enable(bp->pclk);
 		clk_prepare_enable(bp->hclk);
 		clk_prepare_enable(bp->tx_clk);
+		clk_prepare_enable(bp->rx_clk);
 	}
 
 	netif_device_attach(netdev);

drivers/net/ethernet/cadence/macb.h

···
 	u32			caps;
 	unsigned int		dma_burst_length;
 	int	(*clk_init)(struct platform_device *pdev, struct clk **pclk,
-			    struct clk **hclk, struct clk **tx_clk);
+			    struct clk **hclk, struct clk **tx_clk,
+			    struct clk **rx_clk);
 	int	(*init)(struct platform_device *pdev);
 	int	jumbo_max_len;
 };
···
 	struct clk		*pclk;
 	struct clk		*hclk;
 	struct clk		*tx_clk;
+	struct clk		*rx_clk;
 	struct net_device	*dev;
 	struct napi_struct	napi;
 	struct net_device_stats	stats;