File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/regulator/wm831x-isink.c b/drivers/regulator/wm831x-isink.c
new file mode 100644
index 0000000..1442828
--- /dev/null
+++ b/drivers/regulator/wm831x-isink.c
@@ -0,0 +1,252 @@
+/*
+ * wm831x-isink.c  --  Current sink driver for the WM831x series
+ *
+ * Copyright 2009 Wolfson Microelectronics PLC.
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under  the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/slab.h>
+
+#include <linux/mfd/wm831x/core.h>
+#include <linux/mfd/wm831x/regulator.h>
+#include <linux/mfd/wm831x/pdata.h>
+
+#define WM831X_ISINK_MAX_NAME 7
+
+struct wm831x_isink {
+	char name[WM831X_ISINK_MAX_NAME];
+	struct regulator_desc desc;
+	int reg;
+	struct wm831x *wm831x;
+	struct regulator_dev *regulator;
+};
+
+static int wm831x_isink_enable(struct regulator_dev *rdev)
+{
+	struct wm831x_isink *isink = rdev_get_drvdata(rdev);
+	struct wm831x *wm831x = isink->wm831x;
+	int ret;
+
+	/* We have a two stage enable: first start the ISINK... */
+	ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_ENA,
+			      WM831X_CS1_ENA);
+	if (ret != 0)
+		return ret;
+
+	/* ...then enable drive */
+	ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_DRIVE,
+			      WM831X_CS1_DRIVE);
+	if (ret != 0)
+		wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_ENA, 0);
+
+	return ret;
+
+}
+
+static int wm831x_isink_disable(struct regulator_dev *rdev)
+{
+	struct wm831x_isink *isink = rdev_get_drvdata(rdev);
+	struct wm831x *wm831x = isink->wm831x;
+	int ret;
+
+	ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_DRIVE, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_ENA, 0);
+	if (ret < 0)
+		return ret;
+
+	return ret;
+
+}
+
+static int wm831x_isink_is_enabled(struct regulator_dev *rdev)
+{
+	struct wm831x_isink *isink = rdev_get_drvdata(rdev);
+	struct wm831x *wm831x = isink->wm831x;
+	int ret;
+
+	ret = wm831x_reg_read(wm831x, isink->reg);
+	if (ret < 0)
+		return ret;
+
+	if ((ret & (WM831X_CS1_ENA | WM831X_CS1_DRIVE)) ==
+	    (WM831X_CS1_ENA | WM831X_CS1_DRIVE))
+		return 1;
+	else
+		return 0;
+}
+
+static int wm831x_isink_set_current(struct regulator_dev *rdev,
+				    int min_uA, int max_uA)
+{
+	struct wm831x_isink *isink = rdev_get_drvdata(rdev);
+	struct wm831x *wm831x = isink->wm831x;
+	int ret, i;
+
+	for (i = 0; i < ARRAY_SIZE(wm831x_isinkv_values); i++) {
+		int val = wm831x_isinkv_values[i];
+		if (min_uA <= val && val <= max_uA) {
+			ret = wm831x_set_bits(wm831x, isink->reg,
+					      WM831X_CS1_ISEL_MASK, i);
+			return ret;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static int wm831x_isink_get_current(struct regulator_dev *rdev)
+{
+	struct wm831x_isink *isink = rdev_get_drvdata(rdev);
+	struct wm831x *wm831x = isink->wm831x;
+	int ret;
+
+	ret = wm831x_reg_read(wm831x, isink->reg);
+	if (ret < 0)
+		return ret;
+
+	ret &= WM831X_CS1_ISEL_MASK;
+	if (ret > WM831X_ISINK_MAX_ISEL)
+		ret = WM831X_ISINK_MAX_ISEL;
+
+	return wm831x_isinkv_values[ret];
+}
+
+static struct regulator_ops wm831x_isink_ops = {
+	.is_enabled = wm831x_isink_is_enabled,
+	.enable = wm831x_isink_enable,
+	.disable = wm831x_isink_disable,
+	.set_current_limit = wm831x_isink_set_current,
+	.get_current_limit = wm831x_isink_get_current,
+};
+
+static irqreturn_t wm831x_isink_irq(int irq, void *data)
+{
+	struct wm831x_isink *isink = data;
+
+	regulator_notifier_call_chain(isink->regulator,
+				      REGULATOR_EVENT_OVER_CURRENT,
+				      NULL);
+
+	return IRQ_HANDLED;
+}
+
+
+static int wm831x_isink_probe(struct platform_device *pdev)
+{
+	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
+	struct wm831x_pdata *pdata = dev_get_platdata(wm831x->dev);
+	struct wm831x_isink *isink;
+	int id = pdev->id % ARRAY_SIZE(pdata->isink);
+	struct regulator_config config = { };
+	struct resource *res;
+	int ret, irq;
+
+	dev_dbg(&pdev->dev, "Probing ISINK%d\n", id + 1);
+
+	if (pdata == NULL || pdata->isink[id] == NULL)
+		return -ENODEV;
+
+	isink = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_isink),
+			     GFP_KERNEL);
+	if (!isink)
+		return -ENOMEM;
+
+	isink->wm831x = wm831x;
+
+	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
+	if (res == NULL) {
+		dev_err(&pdev->dev, "No REG resource\n");
+		ret = -EINVAL;
+		goto err;
+	}
+	isink->reg = res->start;
+
+	/* For current parts this is correct; probably need to revisit
+	 * in future.
+	 */
+	snprintf(isink->name, sizeof(isink->name), "ISINK%d", id + 1);
+	isink->desc.name = isink->name;
+	isink->desc.id = id;
+	isink->desc.ops = &wm831x_isink_ops;
+	isink->desc.type = REGULATOR_CURRENT;
+	isink->desc.owner = THIS_MODULE;
+
+	config.dev = pdev->dev.parent;
+	config.init_data = pdata->isink[id];
+	config.driver_data = isink;
+
+	isink->regulator = devm_regulator_register(&pdev->dev, &isink->desc,
+						   &config);
+	if (IS_ERR(isink->regulator)) {
+		ret = PTR_ERR(isink->regulator);
+		dev_err(wm831x->dev, "Failed to register ISINK%d: %d\n",
+			id + 1, ret);
+		goto err;
+	}
+
+	irq = wm831x_irq(wm831x, platform_get_irq(pdev, 0));
+	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+					wm831x_isink_irq,
+					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					isink->name,
+					isink);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "Failed to request ISINK IRQ %d: %d\n",
+			irq, ret);
+		goto err;
+	}
+
+	platform_set_drvdata(pdev, isink);
+
+	return 0;
+
+err:
+	return ret;
+}
+
+static struct platform_driver wm831x_isink_driver = {
+	.probe = wm831x_isink_probe,
+	.driver		= {
+		.name	= "wm831x-isink",
+	},
+};
+
+static int __init wm831x_isink_init(void)
+{
+	int ret;
+	ret = platform_driver_register(&wm831x_isink_driver);
+	if (ret != 0)
+		pr_err("Failed to register WM831x ISINK driver: %d\n", ret);
+
+	return ret;
+}
+subsys_initcall(wm831x_isink_init);
+
+static void __exit wm831x_isink_exit(void)
+{
+	platform_driver_unregister(&wm831x_isink_driver);
+}
+module_exit(wm831x_isink_exit);
+
+/* Module information */
+MODULE_AUTHOR("Mark Brown");
+MODULE_DESCRIPTION("WM831x current sink driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:wm831x-isink");