/*
   * 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
  ", 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
  ");
  		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
  ",
  			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
  ",
  			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
  ", 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");