net: mvpp2: Fix clock resource by adding an optional bus clock

On Armada 7K/8K we need to explicitly enable the bus clock. The bus clock
is optional because not all the SoCs need them but at least for Armada
7K/8K it is actually mandatory.

The binding documentation is updating accordingly.
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/marvell-pp2.txt

@@ -21,8 +21,9 @@ Required properties:
 	- main controller clock (for both armada-375-pp2 and armada-7k-pp2)
 	- GOP clock (for both armada-375-pp2 and armada-7k-pp2)
 	- MG clock (only for armada-7k-pp2)
-- clock-names: names of used clocks, must be "pp_clk", "gop_clk" and
-  "mg_clk" (the latter only for armada-7k-pp2).
+	- AXI clock (only for armada-7k-pp2)
+- clock-names: names of used clocks, must be "pp_clk", "gop_clk", "mg_clk"
+  and "axi_clk" (the 2 latter only for armada-7k-pp2).
 
 The ethernet ports are represented by subnodes. At least one port is
 required.
@@ -78,8 +79,9 @@ Example for marvell,armada-7k-pp2:
 cpm_ethernet: ethernet@0 {
 	compatible = "marvell,armada-7k-pp22";
 	reg = <0x0 0x100000>, <0x129000 0xb000>;
-	clocks = <&cpm_syscon0 1 3>, <&cpm_syscon0 1 9>, <&cpm_syscon0 1 5>;
-	clock-names = "pp_clk", "gop_clk", "gp_clk";
+	clocks = <&cpm_syscon0 1 3>, <&cpm_syscon0 1 9>,
+		 <&cpm_syscon0 1 5>, <&cpm_syscon0 1 18>;
+	clock-names = "pp_clk", "gop_clk", "gp_clk", "axi_clk";
 
 	eth0: eth0 {
 		interrupts = <ICU_GRP_NSR 39 IRQ_TYPE_LEVEL_HIGH>,

drivers/net/ethernet/marvell/mvpp2.c

@@ -793,6 +793,7 @@ struct mvpp2 {
 	struct clk *pp_clk;
 	struct clk *gop_clk;
 	struct clk *mg_clk;
+	struct clk *axi_clk;
 
 	/* List of pointers to port structures */
 	struct mvpp2_port **port_list;
@@ -7970,6 +7971,18 @@ static int mvpp2_probe(struct platform_device *pdev)
 		err = clk_prepare_enable(priv->mg_clk);
 		if (err < 0)
 			goto err_gop_clk;
+
+		priv->axi_clk = devm_clk_get(&pdev->dev, "axi_clk");
+		if (IS_ERR(priv->axi_clk)) {
+			err = PTR_ERR(priv->axi_clk);
+			if (err == -EPROBE_DEFER)
+				goto err_gop_clk;
+			priv->axi_clk = NULL;
+		} else {
+			err = clk_prepare_enable(priv->axi_clk);
+			if (err < 0)
+				goto err_gop_clk;
+		}
 	}
 
 	/* Get system's tclk rate */
@@ -8024,6 +8037,7 @@ static int mvpp2_probe(struct platform_device *pdev)
 	return 0;
 
 err_mg_clk:
+	clk_disable_unprepare(priv->axi_clk);
 	if (priv->hw_version == MVPP22)
 		clk_disable_unprepare(priv->mg_clk);
 err_gop_clk:
@@ -8061,6 +8075,7 @@ static int mvpp2_remove(struct platform_device *pdev)
 				  aggr_txq->descs_dma);
 	}
 
+	clk_disable_unprepare(priv->axi_clk);
 	clk_disable_unprepare(priv->mg_clk);
 	clk_disable_unprepare(priv->pp_clk);
 	clk_disable_unprepare(priv->gop_clk);