text: /* linux/drivers/hwmon/s3c-hwmon.c
   *
   * Copyright (C) 2005, 2008, 2009 Simtec Electronics
   *	http://armlinux.simtec.co.uk/
   *	Ben Dooks <ben@simtec.co.uk>
   *
   * S3C24XX/S3C64XX ADC hwmon support
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
  
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/delay.h>
  #include <linux/io.h>
  #include <linux/init.h>
  #include <linux/err.h>
  #include <linux/clk.h>
  #include <linux/interrupt.h>
  #include <linux/platform_device.h>
  
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  
  #include <plat/adc.h>
  #include <plat/hwmon.h>
  
  struct s3c_hwmon_attr {
  	struct sensor_device_attribute	in;
  	struct sensor_device_attribute	label;
  	char				in_name[12];
  	char				label_name[12];
  };
  
  /**
   * struct s3c_hwmon - ADC hwmon client information
   * @lock: Access lock to serialise the conversions.
   * @client: The client we registered with the S3C ADC core.
   * @hwmon_dev: The hwmon device we created.
   * @attr: The holders for the channel attributes.
  */
  struct s3c_hwmon {
  	struct mutex		lock;
  	struct s3c_adc_client	*client;
  	struct device		*hwmon_dev;
  
  	struct s3c_hwmon_attr	attrs[8];
  };
  
  /**
   * s3c_hwmon_read_ch - read a value from a given adc channel.
   * @dev: The device.
   * @hwmon: Our state.
   * @channel: The channel we're reading from.
   *
   * Read a value from the @channel with the proper locking and sleep until
   * either the read completes or we timeout awaiting the ADC core to get
   * back to us.
   */
  static int s3c_hwmon_read_ch(struct device *dev,
  			     struct s3c_hwmon *hwmon, int channel)
  {
  	int ret;
  
  	ret = mutex_lock_interruptible(&hwmon->lock);
  	if (ret < 0)
  		return ret;
  
  	dev_dbg(dev, "reading channel %d\n", channel);
  
  	ret = s3c_adc_read(hwmon->client, channel);
  	mutex_unlock(&hwmon->lock);
  
  	return ret;
  }
  
  #ifdef CONFIG_SENSORS_S3C_RAW
  /**
   * s3c_hwmon_show_raw - show a conversion from the raw channel number.
   * @dev: The device that the attribute belongs to.
   * @attr: The attribute being read.
   * @buf: The result buffer.
   *
   * This show deals with the raw attribute, registered for each possible
   * ADC channel. This does a conversion and returns the raw (un-scaled)
   * value returned from the hardware.
   */
  static ssize_t s3c_hwmon_show_raw(struct device *dev,
  				  struct device_attribute *attr, char *buf)
  {
  	struct s3c_hwmon *adc = platform_get_drvdata(to_platform_device(dev));
  	struct sensor_device_attribute *sa = to_sensor_dev_attr(attr);
  	int ret;
  
  	ret = s3c_hwmon_read_ch(dev, adc, sa->index);
  
  	return  (ret < 0) ? ret : snprintf(buf, PAGE_SIZE, "%d\n", ret);
  }
  
  #define DEF_ADC_ATTR(x)	\
  	static SENSOR_DEVICE_ATTR(adc##x##_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, x)
  
  DEF_ADC_ATTR(0);
  DEF_ADC_ATTR(1);
  DEF_ADC_ATTR(2);
  DEF_ADC_ATTR(3);
  DEF_ADC_ATTR(4);
  DEF_ADC_ATTR(5);
  DEF_ADC_ATTR(6);
  DEF_ADC_ATTR(7);
  
  static struct attribute *s3c_hwmon_attrs[9] = {
  	&sensor_dev_attr_adc0_raw.dev_attr.attr,
  	&sensor_dev_attr_adc1_raw.dev_attr.attr,
  	&sensor_dev_attr_adc2_raw.dev_attr.attr,
  	&sensor_dev_attr_adc3_raw.dev_attr.attr,
  	&sensor_dev_attr_adc4_raw.dev_attr.attr,
  	&sensor_dev_attr_adc5_raw.dev_attr.attr,
  	&sensor_dev_attr_adc6_raw.dev_attr.attr,
  	&sensor_dev_attr_adc7_raw.dev_attr.attr,
  	NULL,
  };
  
  static struct attribute_group s3c_hwmon_attrgroup = {
  	.attrs	= s3c_hwmon_attrs,
  };
  
  static inline int s3c_hwmon_add_raw(struct device *dev)
  {
  	return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup);
  }
  
  static inline void s3c_hwmon_remove_raw(struct device *dev)
  {
  	sysfs_remove_group(&dev->kobj, &s3c_hwmon_attrgroup);
  }
  
  #else
  
  static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; }
  static inline void s3c_hwmon_remove_raw(struct device *dev) { }
  
  #endif /* CONFIG_SENSORS_S3C_RAW */
  
  /**
   * s3c_hwmon_ch_show - show value of a given channel
   * @dev: The device that the attribute belongs to.
   * @attr: The attribute being read.
   * @buf: The result buffer.
   *
   * Read a value from the ADC and scale it before returning it to the
   * caller. The scale factor is gained from the channel configuration
   * passed via the platform data when the device was registered.
   */
  static ssize_t s3c_hwmon_ch_show(struct device *dev,
  				 struct device_attribute *attr,
  				 char *buf)
  {
  	struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
  	struct s3c_hwmon *hwmon = platform_get_drvdata(to_platform_device(dev));
  	struct s3c_hwmon_pdata *pdata = dev->platform_data;
  	struct s3c_hwmon_chcfg *cfg;
  	int ret;
  
  	cfg = pdata->in[sen_attr->index];
  
  	ret = s3c_hwmon_read_ch(dev, hwmon, sen_attr->index);
  	if (ret < 0)
  		return ret;
  
  	ret *= cfg->mult;
  	ret = DIV_ROUND_CLOSEST(ret, cfg->div);
  
  	return snprintf(buf, PAGE_SIZE, "%d\n", ret);
  }
  
  /**
   * s3c_hwmon_label_show - show label name of the given channel.
   * @dev: The device that the attribute belongs to.
   * @attr: The attribute being read.
   * @buf: The result buffer.
   *
   * Return the label name of a given channel
   */
  static ssize_t s3c_hwmon_label_show(struct device *dev,
  				    struct device_attribute *attr,
  				    char *buf)
  {
  	struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
  	struct s3c_hwmon_pdata *pdata = dev->platform_data;
  	struct s3c_hwmon_chcfg *cfg;
  
  	cfg = pdata->in[sen_attr->index];
  
  	return snprintf(buf, PAGE_SIZE, "%s\n", cfg->name);
  }
  
  /**
   * s3c_hwmon_create_attr - create hwmon attribute for given channel.
   * @dev: The device to create the attribute on.
   * @cfg: The channel configuration passed from the platform data.
   * @channel: The ADC channel number to process.
   *
   * Create the scaled attribute for use with hwmon from the specified
   * platform data in @pdata. The sysfs entry is handled by the routine
   * s3c_hwmon_ch_show().
   *
   * The attribute name is taken from the configuration data if present
   * otherwise the name is taken by concatenating in_ with the channel
   * number.
   */
  static int s3c_hwmon_create_attr(struct device *dev,
  				 struct s3c_hwmon_chcfg *cfg,
  				 struct s3c_hwmon_attr *attrs,
  				 int channel)
  {
  	struct sensor_device_attribute *attr;
  	int ret;
  
  	snprintf(attrs->in_name, sizeof(attrs->in_name), "in%d_input", channel);
  
  	attr = &attrs->in;
  	attr->index = channel;
  	sysfs_attr_init(&attr->dev_attr.attr);
  	attr->dev_attr.attr.name  = attrs->in_name;
  	attr->dev_attr.attr.mode  = S_IRUGO;
  	attr->dev_attr.show = s3c_hwmon_ch_show;
  
  	ret =  device_create_file(dev, &attr->dev_attr);
  	if (ret < 0) {
  		dev_err(dev, "failed to create input attribute\n");
  		return ret;
  	}
  
  	/* if this has a name, add a label */
  	if (cfg->name) {
  		snprintf(attrs->label_name, sizeof(attrs->label_name),
  			 "in%d_label", channel);
  
  		attr = &attrs->label;
  		attr->index = channel;
  		sysfs_attr_init(&attr->dev_attr.attr);
  		attr->dev_attr.attr.name  = attrs->label_name;
  		attr->dev_attr.attr.mode  = S_IRUGO;
  		attr->dev_attr.show = s3c_hwmon_label_show;
  
  		ret = device_create_file(dev, &attr->dev_attr);
  		if (ret < 0) {
  			device_remove_file(dev, &attrs->in.dev_attr);
  			dev_err(dev, "failed to create label attribute\n");
  		}
  	}
  
  	return ret;
  }
  
  static void s3c_hwmon_remove_attr(struct device *dev,
  				  struct s3c_hwmon_attr *attrs)
  {
  	device_remove_file(dev, &attrs->in.dev_attr);
  	device_remove_file(dev, &attrs->label.dev_attr);
  }
  
  /**
   * s3c_hwmon_probe - device probe entry.
   * @dev: The device being probed.
  */
  static int __devinit s3c_hwmon_probe(struct platform_device *dev)
  {
  	struct s3c_hwmon_pdata *pdata = dev->dev.platform_data;
  	struct s3c_hwmon *hwmon;
  	int ret = 0;
  	int i;
  
  	if (!pdata) {
  		dev_err(&dev->dev, "no platform data supplied\n");
  		return -EINVAL;
  	}
  
  	hwmon = devm_kzalloc(&dev->dev, sizeof(struct s3c_hwmon), GFP_KERNEL);
  	if (hwmon == NULL) {
  		dev_err(&dev->dev, "no memory\n");
  		return -ENOMEM;
  	}
  
  	platform_set_drvdata(dev, hwmon);
  
  	mutex_init(&hwmon->lock);
  
  	/* Register with the core ADC driver. */
  
  	hwmon->client = s3c_adc_register(dev, NULL, NULL, 0);
  	if (IS_ERR(hwmon->client)) {
  		dev_err(&dev->dev, "cannot register adc\n");
  		return PTR_ERR(hwmon->client);
  	}
  
  	/* add attributes for our adc devices. */
  
  	ret = s3c_hwmon_add_raw(&dev->dev);
  	if (ret)
  		goto err_registered;
  
  	/* register with the hwmon core */
  
  	hwmon->hwmon_dev = hwmon_device_register(&dev->dev);
  	if (IS_ERR(hwmon->hwmon_dev)) {
  		dev_err(&dev->dev, "error registering with hwmon\n");
  		ret = PTR_ERR(hwmon->hwmon_dev);
  		goto err_raw_attribute;
  	}
  
  	for (i = 0; i < ARRAY_SIZE(pdata->in); i++) {
  		struct s3c_hwmon_chcfg *cfg = pdata->in[i];
  
  		if (!cfg)
  			continue;
  
  		if (cfg->mult >= 0x10000)
  			dev_warn(&dev->dev,
  				 "channel %d multiplier too large\n",
  				 i);
  
  		if (cfg->div == 0) {
  			dev_err(&dev->dev, "channel %d divider zero\n", i);
  			continue;
  		}
  
  		ret = s3c_hwmon_create_attr(&dev->dev, pdata->in[i],
  					    &hwmon->attrs[i], i);
  		if (ret) {
  			dev_err(&dev->dev,
  					"error creating channel %d\n", i);
  
  			for (i--; i >= 0; i--)
  				s3c_hwmon_remove_attr(&dev->dev,
  							      &hwmon->attrs[i]);
  
  			goto err_hwmon_register;
  		}
  	}
  
  	return 0;
  
   err_hwmon_register:
  	hwmon_device_unregister(hwmon->hwmon_dev);
  
   err_raw_attribute:
  	s3c_hwmon_remove_raw(&dev->dev);
  
   err_registered:
  	s3c_adc_release(hwmon->client);
  
  	return ret;
  }
  
  static int __devexit s3c_hwmon_remove(struct platform_device *dev)
  {
  	struct s3c_hwmon *hwmon = platform_get_drvdata(dev);
  	int i;
  
  	s3c_hwmon_remove_raw(&dev->dev);
  
  	for (i = 0; i < ARRAY_SIZE(hwmon->attrs); i++)
  		s3c_hwmon_remove_attr(&dev->dev, &hwmon->attrs[i]);
  
  	hwmon_device_unregister(hwmon->hwmon_dev);
  	s3c_adc_release(hwmon->client);
  
  	return 0;
  }
  
  static struct platform_driver s3c_hwmon_driver = {
  	.driver	= {
  		.name		= "s3c-hwmon",
  		.owner		= THIS_MODULE,
  	},
  	.probe		= s3c_hwmon_probe,
  	.remove		= __devexit_p(s3c_hwmon_remove),
  };
  
  module_platform_driver(s3c_hwmon_driver);
  
  MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
  MODULE_DESCRIPTION("S3C ADC HWMon driver");
  MODULE_LICENSE("GPL v2");
  MODULE_ALIAS("platform:s3c-hwmon");
  