iio: adc: Add dt support for turning on the phy in exynos-adc

Without this change the exynos adc controller needed to have its phy
enabled in some out-of-driver C code.  Add support for specifying the
phy enable register by listing it in the reg list.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Tested-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt

@@ -15,7 +15,7 @@ Required properties:
 			Must be "samsung,exynos-adc-v2" for
 				future controllers.
 - reg:			Contains ADC register address range (base address and
-			length).
+			length) and the address of the phy enable register.
 - interrupts: 		Contains the interrupt information for the timer. The
 			format is being dependent on which interrupt controller
 			the Samsung device uses.
@@ -27,7 +27,7 @@ Example: adding device info in dtsi file
 
 adc: adc@12D10000 {
 	compatible = "samsung,exynos-adc-v1";
-	reg = <0x12D10000 0x100>;
+	reg = <0x12D10000 0x100>, <0x10040718 0x4>;
 	interrupts = <0 106 0>;
 	#io-channel-cells = <1>;
 	io-channel-ranges;

drivers/iio/adc/exynos_adc.c

@@ -85,6 +85,7 @@ enum adc_version {
 
 struct exynos_adc {
 	void __iomem		*regs;
+	void __iomem		*enable_reg;
 	struct clk		*clk;
 	unsigned int		irq;
 	struct regulator	*vdd;
@@ -269,13 +270,19 @@ static int exynos_adc_probe(struct platform_device *pdev)
 	info = iio_priv(indio_dev);
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-
 	info->regs = devm_request_and_ioremap(&pdev->dev, mem);
 	if (!info->regs) {
 		ret = -ENOMEM;
 		goto err_iio;
 	}
 
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	info->enable_reg = devm_request_and_ioremap(&pdev->dev, mem);
+	if (!info->enable_reg) {
+		ret = -ENOMEM;
+		goto err_iio;
+	}
+
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		dev_err(&pdev->dev, "no irq resource?\n");
@@ -295,6 +302,8 @@ static int exynos_adc_probe(struct platform_device *pdev)
 		goto err_iio;
 	}
 
+	writel(1, info->enable_reg);
+
 	info->clk = devm_clk_get(&pdev->dev, "adc");
 	if (IS_ERR(info->clk)) {
 		dev_err(&pdev->dev, "failed getting clock, err = %ld\n",
@@ -370,6 +379,7 @@ static int exynos_adc_remove(struct platform_device *pdev)
 				exynos_adc_remove_devices);
 	regulator_disable(info->vdd);
 	clk_disable_unprepare(info->clk);
+	writel(0, info->enable_reg);
 	iio_device_unregister(indio_dev);
 	free_irq(info->irq, info);
 	iio_device_free(indio_dev);
@@ -395,6 +405,7 @@ static int exynos_adc_suspend(struct device *dev)
 	}
 
 	clk_disable_unprepare(info->clk);
+	writel(0, info->enable_reg);
 	regulator_disable(info->vdd);
 
 	return 0;
@@ -410,6 +421,7 @@ static int exynos_adc_resume(struct device *dev)
 	if (ret)
 		return ret;
 
+	writel(1, info->enable_reg);
 	clk_prepare_enable(info->clk);
 
 	exynos_adc_hw_init(info);