clk: apn806: Add eMMC clock to system controller driver

Add fixed clock of 400MHz to system controller driver.  This clock is
used as SD/eMMC clock source.

Signed-off-by: Konstantin Porotchkin <kostap@marvell.com>
Reviewed-by: Omri Itach <omrii@marvell.com>
Reviewed-by: Hanna Hawa <hannah@marvell.com>
[fixed up conflicts, added error handling --rmk]
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

arch/arm64/boot/dts/marvell/armada-ap806.dtsi

@@ -235,7 +235,8 @@
 				#clock-cells = <1>;
 				clock-output-names = "ap-cpu-cluster-0",
 						     "ap-cpu-cluster-1",
-						     "ap-fixed", "ap-mss";
+						     "ap-fixed", "ap-mss",
+						     "ap-emmc";
 				reg = <0x6f4000 0x1000>;
 			};
 		};

drivers/clk/mvebu/ap806-system-controller.c

@@ -23,7 +23,7 @@
 #define AP806_SAR_REG			0x400
 #define AP806_SAR_CLKFREQ_MODE_MASK	0x1f
 
-#define AP806_CLK_NUM			4
+#define AP806_CLK_NUM			5
 
 static struct clk *ap806_clks[AP806_CLK_NUM];
 
@@ -135,6 +135,17 @@ static int ap806_syscon_clk_probe(struct platform_device *pdev)
 		goto fail3;
 	}
 
+	/* eMMC Clock is fixed clock divided by 3 */
+	of_property_read_string_index(np, "clock-output-names",
+				      4, &name);
+	ap806_clks[4] = clk_register_fixed_factor(NULL, name, fixedclk_name,
+						  0, 1, 3);
+	if (IS_ERR(ap806_clks[4])) {
+		ret = PTR_ERR(ap806_clks[4]);
+		goto fail4;
+	}
+
+	of_clk_add_provider(np, of_clk_src_onecell_get, &ap806_clk_data);
 	ret = of_clk_add_provider(np, of_clk_src_onecell_get, &ap806_clk_data);
 	if (ret)
 		goto fail_clk_add;
@@ -142,6 +153,8 @@ static int ap806_syscon_clk_probe(struct platform_device *pdev)
 	return 0;
 
 fail_clk_add:
+	clk_unregister_fixed_factor(ap806_clks[4]);
+fail4:
 	clk_unregister_fixed_factor(ap806_clks[3]);
 fail3:
 	clk_unregister_fixed_rate(ap806_clks[2]);