text: /*
   * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
   * JZ4740 SoC HWMON driver
   *
   * 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.
   *
   * You should have received a copy of the GNU General Public License along
   * with this program; if not, write to the Free Software Foundation, Inc.,
   * 675 Mass Ave, Cambridge, MA 02139, USA.
   *
   */
  
  #include <linux/err.h>
  #include <linux/interrupt.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include <linux/platform_device.h>
  #include <linux/slab.h>
  #include <linux/io.h>
  
  #include <linux/completion.h>
  #include <linux/mfd/core.h>
  
  #include <linux/hwmon.h>
  
  struct jz4740_hwmon {
  	void __iomem *base;
  	int irq;
  	const struct mfd_cell *cell;
  	struct platform_device *pdev;
  	struct completion read_completion;
  	struct mutex lock;
  };
  
  static irqreturn_t jz4740_hwmon_irq(int irq, void *data)
  {
  	struct jz4740_hwmon *hwmon = data;
  
  	complete(&hwmon->read_completion);
  	return IRQ_HANDLED;
  }
  
  static ssize_t jz4740_hwmon_read_adcin(struct device *dev,
  	struct device_attribute *dev_attr, char *buf)
  {
  	struct jz4740_hwmon *hwmon = dev_get_drvdata(dev);
  	struct platform_device *pdev = hwmon->pdev;
  	struct completion *completion = &hwmon->read_completion;
  	long t;
  	unsigned long val;
  	int ret;
  
  	mutex_lock(&hwmon->lock);
  
  	reinit_completion(completion);
  
  	enable_irq(hwmon->irq);
  	hwmon->cell->enable(pdev);
  
  	t = wait_for_completion_interruptible_timeout(completion, HZ);
  
  	if (t > 0) {
  		val = readw(hwmon->base) & 0xfff;
  		val = (val * 3300) >> 12;
  		ret = sprintf(buf, "%lu\n", val);
  	} else {
  		ret = t ? t : -ETIMEDOUT;
  	}
  
  	hwmon->cell->disable(pdev);
  	disable_irq(hwmon->irq);
  
  	mutex_unlock(&hwmon->lock);
  
  	return ret;
  }
  
  static DEVICE_ATTR(in0_input, S_IRUGO, jz4740_hwmon_read_adcin, NULL);
  
  static struct attribute *jz4740_attrs[] = {
  	&dev_attr_in0_input.attr,
  	NULL
  };
  
  ATTRIBUTE_GROUPS(jz4740);
  
  static int jz4740_hwmon_probe(struct platform_device *pdev)
  {
  	int ret;
  	struct device *dev = &pdev->dev;
  	struct jz4740_hwmon *hwmon;
  	struct device *hwmon_dev;
  	struct resource *mem;
  
  	hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
  	if (!hwmon)
  		return -ENOMEM;
  
  	hwmon->cell = mfd_get_cell(pdev);
  
  	hwmon->irq = platform_get_irq(pdev, 0);
  	if (hwmon->irq < 0) {
  		dev_err(&pdev->dev, "Failed to get platform irq: %d\n",
  			hwmon->irq);
  		return hwmon->irq;
  	}
  
  	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	hwmon->base = devm_ioremap_resource(&pdev->dev, mem);
  	if (IS_ERR(hwmon->base))
  		return PTR_ERR(hwmon->base);
  
  	hwmon->pdev = pdev;
  	init_completion(&hwmon->read_completion);
  	mutex_init(&hwmon->lock);
  
  	ret = devm_request_irq(dev, hwmon->irq, jz4740_hwmon_irq, 0,
  			       pdev->name, hwmon);
  	if (ret) {
  		dev_err(&pdev->dev, "Failed to request irq: %d\n", ret);
  		return ret;
  	}
  	disable_irq(hwmon->irq);
  
  	hwmon_dev = devm_hwmon_device_register_with_groups(dev, "jz4740", hwmon,
  							   jz4740_groups);
  	return PTR_ERR_OR_ZERO(hwmon_dev);
  }
  
  static struct platform_driver jz4740_hwmon_driver = {
  	.probe	= jz4740_hwmon_probe,
  	.driver = {
  		.name = "jz4740-hwmon",
  	},
  };
  
  module_platform_driver(jz4740_hwmon_driver);
  
  MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
  MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:jz4740-hwmon");
  