net: ethernet: mediatek: fix incorrect return value of devm_clk_get with EPROBE_DEFER

1) If the return value of devm_clk_get is EPROBE_DEFER, we should
defer probing the driver. The change is verified and works based
on 4.8-rc1 staying with the latest clk-next code for MT7623.
2) Changing with the usage of loops to work out if all clocks
required are fine

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -50,6 +50,10 @@ static const struct mtk_ethtool_stats {
 	MTK_ETHTOOL_STAT(rx_flow_control_packets),
 };
 
+static const char * const mtk_clks_source_name[] = {
+	"ethif", "esw", "gp1", "gp2"
+};
+
 void mtk_w32(struct mtk_eth *eth, u32 val, unsigned reg)
 {
 	__raw_writel(val, eth->base + reg);
@@ -1814,6 +1818,7 @@ static int mtk_probe(struct platform_device *pdev)
 	if (!eth)
 		return -ENOMEM;
 
+	eth->dev = &pdev->dev;
 	eth->base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(eth->base))
 		return PTR_ERR(eth->base);
@@ -1848,21 +1853,21 @@ static int mtk_probe(struct platform_device *pdev)
 			return -ENXIO;
 		}
 	}
+	for (i = 0; i < ARRAY_SIZE(eth->clks); i++) {
+		eth->clks[i] = devm_clk_get(eth->dev,
+					    mtk_clks_source_name[i]);
+		if (IS_ERR(eth->clks[i])) {
+			if (PTR_ERR(eth->clks[i]) == -EPROBE_DEFER)
+				return -EPROBE_DEFER;
+			return -ENODEV;
+		}
+	}
 
-	eth->clk_ethif = devm_clk_get(&pdev->dev, "ethif");
-	eth->clk_esw = devm_clk_get(&pdev->dev, "esw");
-	eth->clk_gp1 = devm_clk_get(&pdev->dev, "gp1");
-	eth->clk_gp2 = devm_clk_get(&pdev->dev, "gp2");
-	if (IS_ERR(eth->clk_esw) || IS_ERR(eth->clk_gp1) ||
-	    IS_ERR(eth->clk_gp2) || IS_ERR(eth->clk_ethif))
-		return -ENODEV;
-
-	clk_prepare_enable(eth->clk_ethif);
-	clk_prepare_enable(eth->clk_esw);
-	clk_prepare_enable(eth->clk_gp1);
-	clk_prepare_enable(eth->clk_gp2);
+	clk_prepare_enable(eth->clks[MTK_CLK_ETHIF]);
+	clk_prepare_enable(eth->clks[MTK_CLK_ESW]);
+	clk_prepare_enable(eth->clks[MTK_CLK_GP1]);
+	clk_prepare_enable(eth->clks[MTK_CLK_GP2]);
 
-	eth->dev = &pdev->dev;
 	eth->msg_enable = netif_msg_init(mtk_msg_level, MTK_DEFAULT_MSG_ENABLE);
 	INIT_WORK(&eth->pending_work, mtk_pending_work);
 
@@ -1905,10 +1910,10 @@ static int mtk_remove(struct platform_device *pdev)
 {
 	struct mtk_eth *eth = platform_get_drvdata(pdev);
 
-	clk_disable_unprepare(eth->clk_ethif);
-	clk_disable_unprepare(eth->clk_esw);
-	clk_disable_unprepare(eth->clk_gp1);
-	clk_disable_unprepare(eth->clk_gp2);
+	clk_disable_unprepare(eth->clks[MTK_CLK_ETHIF]);
+	clk_disable_unprepare(eth->clks[MTK_CLK_ESW]);
+	clk_disable_unprepare(eth->clks[MTK_CLK_GP1]);
+	clk_disable_unprepare(eth->clks[MTK_CLK_GP2]);
 
 	netif_napi_del(&eth->tx_napi);
 	netif_napi_del(&eth->rx_napi);

drivers/net/ethernet/mediatek/mtk_eth_soc.h

@@ -290,6 +290,17 @@ enum mtk_tx_flags {
 	MTK_TX_FLAGS_PAGE0	= 0x02,
 };
 
+/* This enum allows us to identify how the clock is defined on the array of the
+ * clock in the order
+ */
+enum mtk_clks_map {
+	MTK_CLK_ETHIF,
+	MTK_CLK_ESW,
+	MTK_CLK_GP1,
+	MTK_CLK_GP2,
+	MTK_CLK_MAX
+};
+
 /* struct mtk_tx_buf -	This struct holds the pointers to the memory pointed at
  *			by the TX descriptor	s
  * @skb:		The SKB pointer of the packet being sent
@@ -370,10 +381,7 @@ struct mtk_rx_ring {
  * @scratch_ring:	Newer SoCs need memory for a second HW managed TX ring
  * @phy_scratch_ring:	physical address of scratch_ring
  * @scratch_head:	The scratch memory that scratch_ring points to.
- * @clk_ethif:		The ethif clock
- * @clk_esw:		The switch clock
- * @clk_gp1:		The gmac1 clock
- * @clk_gp2:		The gmac2 clock
+ * @clks:		clock array for all clocks required
  * @mii_bus:		If there is a bus we need to create an instance for it
  * @pending_work:	The workqueue used to reset the dma ring
  */
@@ -400,10 +408,8 @@ struct mtk_eth {
 	struct mtk_tx_dma		*scratch_ring;
 	dma_addr_t			phy_scratch_ring;
 	void				*scratch_head;
-	struct clk			*clk_ethif;
-	struct clk			*clk_esw;
-	struct clk			*clk_gp1;
-	struct clk			*clk_gp2;
+	struct clk			*clks[MTK_CLK_MAX];
+
 	struct mii_bus			*mii_bus;
 	struct work_struct		pending_work;
 };