clk: max77686: Register OF clock provider

If max77686 chip is instantiated from device tree, it is desirable to
have an OF clock provider to allow device tree based look-up of clocks.
This patch adds OF clock provider registration to the clk-max77686
driver.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

Documentation/devicetree/bindings/clock/maxim,max77686.txt

+Binding for Maxim MAX77686 32k clock generator block
+
+This is a part of device tree bindings of MAX77686 multi-function device.
+More information can be found in bindings/mfd/max77686.txt file.
+
+The MAX77686 contains three 32.768khz clock outputs that can be controlled
+(gated/ungated) over I2C.
+
+Following properties should be presend in main device node of the MFD chip.
+
+Required properties:
+- #clock-cells: simple one-cell clock specifier format is used, where the
+  only cell is used as an index of the clock inside the provider. Following
+  indices are allowed:
+    - 0: 32khz_ap clock,
+    - 1: 32khz_cp clock,
+    - 2: 32khz_pmic clock.
+
+Example: Node of the MFD chip
+
+	max77686: max77686@09 {
+		compatible = "maxim,max77686";
+		interrupt-parent = <&wakeup_eint>;
+		interrupts = <26 0>;
+		reg = <0x09>;
+		#clock-cells = <1>;
+
+		/* ... */
+	};
+
+Example: Clock consumer node
+
+	foo@0 {
+		compatible = "bar,foo";
+		/* ... */
+		clock-names = "my-clock";
+		clocks = <&max77686 2>;
+	};

Documentation/devicetree/bindings/mfd/max77686.txt

@@ -7,6 +7,9 @@ different i2c slave address,presently for which we are statically creating i2c
 client while probing.This document describes the binding for mfd device and
 PMIC submodule.
 
+Binding for the built-in 32k clock generator block is defined separately
+in bindings/clk/maxim,max77686.txt file.
+
 Required properties:
 - compatible : Must be "maxim,max77686";
 - reg : Specifies the i2c slave address of PMIC block.

drivers/clk/clk-max77686.c

@@ -169,6 +169,26 @@ static int max77686_clk_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, clocks);
 
+	if (iodev->dev->of_node) {
+		struct clk_onecell_data *of_data;
+
+		of_data = devm_kzalloc(&pdev->dev,
+					sizeof(*of_data), GFP_KERNEL);
+		if (!of_data) {
+			ret = -ENOMEM;
+			goto err_clocks;
+		}
+
+		of_data->clks = clocks;
+		of_data->clk_num = MAX77686_CLKS_NUM;
+		ret = of_clk_add_provider(iodev->dev->of_node,
+					of_clk_src_onecell_get, of_data);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to register OF clock provider\n");
+			goto err_clocks;
+		}
+	}
+
 	return 0;
 
 err_clocks:
@@ -182,9 +202,13 @@ static int max77686_clk_probe(struct platform_device *pdev)
 
 static int max77686_clk_remove(struct platform_device *pdev)
 {
+	struct max77686_dev *iodev = dev_get_drvdata(pdev->dev.parent);
 	struct clk **clocks = platform_get_drvdata(pdev);
 	int i;
 
+	if (iodev->dev->of_node)
+		of_clk_del_provider(iodev->dev->of_node);
+
 	for (i = 0; i < MAX77686_CLKS_NUM; i++) {
 		struct clk_hw *hw = __clk_get_hw(clocks[i]);
 		struct max77686_clk *max77686 = to_max77686_clk(hw);