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ad7418.c

/*
 * An hwmon driver for the Analog Devices AD7416/17/18
 * Copyright (C) 2006-07 Tower Technologies
 *
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 *
 * Based on lm75.c
 * Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
 *
 * 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 - version 2.
 */

#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/delay.h>

#include "lm75.h"

#define DRV_VERSION "0.3"

/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x28, I2C_CLIENT_END };
/* Insmod parameters */
I2C_CLIENT_INSMOD_3(ad7416, ad7417, ad7418);

/* AD7418 registers */
#define AD7418_REG_TEMP_IN    0x00
#define AD7418_REG_CONF       0x01
#define AD7418_REG_TEMP_HYST  0x02
#define AD7418_REG_TEMP_OS    0x03
#define AD7418_REG_ADC        0x04
#define AD7418_REG_CONF2      0x05

#define AD7418_REG_ADC_CH(x)  ((x) << 5)
#define AD7418_CH_TEMP        AD7418_REG_ADC_CH(0)

static const u8 AD7418_REG_TEMP[] = { AD7418_REG_TEMP_IN,
                              AD7418_REG_TEMP_HYST,
                              AD7418_REG_TEMP_OS };

struct ad7418_data {
      struct i2c_client client;
      struct device           *hwmon_dev;
      struct attribute_group  attrs;
      enum chips        type;
      struct mutex            lock;
      int               adc_max;    /* number of ADC channels */
      char              valid;
      unsigned long           last_updated;     /* In jiffies */
      s16               temp[3];    /* Register values */
      u16               in[4];
};

static int ad7418_attach_adapter(struct i2c_adapter *adapter);
static int ad7418_detect(struct i2c_adapter *adapter, int address, int kind);
static int ad7418_detach_client(struct i2c_client *client);

static struct i2c_driver ad7418_driver = {
      .driver = {
            .name = "ad7418",
      },
      .attach_adapter   = ad7418_attach_adapter,
      .detach_client    = ad7418_detach_client,
};

/* All registers are word-sized, except for the configuration registers.
 * AD7418 uses a high-byte first convention. Do NOT use those functions to
 * access the configuration registers CONF and CONF2, as they are byte-sized.
 */
static inline int ad7418_read(struct i2c_client *client, u8 reg)
{
      return swab16(i2c_smbus_read_word_data(client, reg));
}

static inline int ad7418_write(struct i2c_client *client, u8 reg, u16 value)
{
      return i2c_smbus_write_word_data(client, reg, swab16(value));
}

static void ad7418_init_client(struct i2c_client *client)
{
      struct ad7418_data *data = i2c_get_clientdata(client);

      int reg = i2c_smbus_read_byte_data(client, AD7418_REG_CONF);
      if (reg < 0) {
            dev_err(&client->dev, "cannot read configuration register\n");
      } else {
            dev_info(&client->dev, "configuring for mode 1\n");
            i2c_smbus_write_byte_data(client, AD7418_REG_CONF, reg & 0xfe);

            if (data->type == ad7417 || data->type == ad7418)
                  i2c_smbus_write_byte_data(client,
                                    AD7418_REG_CONF2, 0x00);
      }
}

static struct ad7418_data *ad7418_update_device(struct device *dev)
{
      struct i2c_client *client = to_i2c_client(dev);
      struct ad7418_data *data = i2c_get_clientdata(client);

      mutex_lock(&data->lock);

      if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
            || !data->valid) {
            u8 cfg;
            int i, ch;

            /* read config register and clear channel bits */
            cfg = i2c_smbus_read_byte_data(client, AD7418_REG_CONF);
            cfg &= 0x1F;

            i2c_smbus_write_byte_data(client, AD7418_REG_CONF,
                                    cfg | AD7418_CH_TEMP);
            udelay(30);

            for (i = 0; i < 3; i++) {
                  data->temp[i] = ad7418_read(client, AD7418_REG_TEMP[i]);
            }

            for (i = 0, ch = 4; i < data->adc_max; i++, ch--) {
                  i2c_smbus_write_byte_data(client,
                              AD7418_REG_CONF,
                              cfg | AD7418_REG_ADC_CH(ch));

                  udelay(15);
                  data->in[data->adc_max - 1 - i] =
                        ad7418_read(client, AD7418_REG_ADC);
            }

            /* restore old configuration value */
            ad7418_write(client, AD7418_REG_CONF, cfg);

            data->last_updated = jiffies;
            data->valid = 1;
      }

      mutex_unlock(&data->lock);

      return data;
}

static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
                  char *buf)
{
      struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
      struct ad7418_data *data = ad7418_update_device(dev);
      return sprintf(buf, "%d\n",
            LM75_TEMP_FROM_REG(data->temp[attr->index]));
}

static ssize_t show_adc(struct device *dev, struct device_attribute *devattr,
                  char *buf)
{
      struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
      struct ad7418_data *data = ad7418_update_device(dev);

      return sprintf(buf, "%d\n",
            ((data->in[attr->index] >> 6) * 2500 + 512) / 1024);
}

static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
                  const char *buf, size_t count)
{
      struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
      struct i2c_client *client = to_i2c_client(dev);
      struct ad7418_data *data = i2c_get_clientdata(client);
      long temp = simple_strtol(buf, NULL, 10);

      mutex_lock(&data->lock);
      data->temp[attr->index] = LM75_TEMP_TO_REG(temp);
      ad7418_write(client, AD7418_REG_TEMP[attr->index], data->temp[attr->index]);
      mutex_unlock(&data->lock);
      return count;
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
                        show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
                        show_temp, set_temp, 2);

static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, show_adc, NULL, 0);
static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, show_adc, NULL, 1);
static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, show_adc, NULL, 2);
static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, show_adc, NULL, 3);

static int ad7418_attach_adapter(struct i2c_adapter *adapter)
{
      if (!(adapter->class & I2C_CLASS_HWMON))
            return 0;
      return i2c_probe(adapter, &addr_data, ad7418_detect);
}

static struct attribute *ad7416_attributes[] = {
      &sensor_dev_attr_temp1_max.dev_attr.attr,
      &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
      &sensor_dev_attr_temp1_input.dev_attr.attr,
      NULL
};

static struct attribute *ad7417_attributes[] = {
      &sensor_dev_attr_temp1_max.dev_attr.attr,
      &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
      &sensor_dev_attr_temp1_input.dev_attr.attr,
      &sensor_dev_attr_in1_input.dev_attr.attr,
      &sensor_dev_attr_in2_input.dev_attr.attr,
      &sensor_dev_attr_in3_input.dev_attr.attr,
      &sensor_dev_attr_in4_input.dev_attr.attr,
      NULL
};

static struct attribute *ad7418_attributes[] = {
      &sensor_dev_attr_temp1_max.dev_attr.attr,
      &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
      &sensor_dev_attr_temp1_input.dev_attr.attr,
      &sensor_dev_attr_in1_input.dev_attr.attr,
      NULL
};

static int ad7418_detect(struct i2c_adapter *adapter, int address, int kind)
{
      struct i2c_client *client;
      struct ad7418_data *data;
      int err = 0;

      if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
                              I2C_FUNC_SMBUS_WORD_DATA))
            goto exit;

      if (!(data = kzalloc(sizeof(struct ad7418_data), GFP_KERNEL))) {
            err = -ENOMEM;
            goto exit;
      }

      client = &data->client;
      client->addr = address;
      client->adapter = adapter;
      client->driver = &ad7418_driver;

      i2c_set_clientdata(client, data);

      mutex_init(&data->lock);

      /* AD7418 has a curious behaviour on registers 6 and 7. They
       * both always read 0xC071 and are not documented on the datasheet.
       * We use them to detect the chip.
       */
      if (kind <= 0) {
            int reg, reg6, reg7;

            /* the AD7416 lies within this address range, but I have
             * no means to check.
             */
            if (address >= 0x48 && address <= 0x4f) {
                  /* XXX add tests for AD7416 here */
                  /* data->type = ad7416; */
            }
            /* here we might have AD7417 or AD7418 */
            else if (address >= 0x28 && address <= 0x2f) {
                  reg6 = i2c_smbus_read_word_data(client, 0x06);
                  reg7 = i2c_smbus_read_word_data(client, 0x07);

                  if (address == 0x28 && reg6 == 0xC071 && reg7 == 0xC071)
                        data->type = ad7418;

                  /* XXX add tests for AD7417 here */


                  /* both AD7417 and AD7418 have bits 0-5 of
                   * the CONF2 register at 0
                   */
                  reg = i2c_smbus_read_byte_data(client,
                                          AD7418_REG_CONF2);
                  if (reg & 0x3F)
                        data->type = any_chip; /* detection failed */
            }
      } else {
            dev_dbg(&adapter->dev, "detection forced\n");
      }

      if (kind > 0)
            data->type = kind;
      else if (kind < 0 && data->type == any_chip) {
            err = -ENODEV;
            goto exit_free;
      }

      switch (data->type) {
      case any_chip:
      case ad7416:
            data->adc_max = 0;
            data->attrs.attrs = ad7416_attributes;
            strlcpy(client->name, "ad7416", I2C_NAME_SIZE);
            break;

      case ad7417:
            data->adc_max = 4;
            data->attrs.attrs = ad7417_attributes;
            strlcpy(client->name, "ad7417", I2C_NAME_SIZE);
            break;

      case ad7418:
            data->adc_max = 1;
            data->attrs.attrs = ad7418_attributes;
            strlcpy(client->name, "ad7418", I2C_NAME_SIZE);
            break;
      }

      if ((err = i2c_attach_client(client)))
            goto exit_free;

      dev_info(&client->dev, "%s chip found\n", client->name);

      /* Initialize the AD7418 chip */
      ad7418_init_client(client);

      /* Register sysfs hooks */
      if ((err = sysfs_create_group(&client->dev.kobj, &data->attrs)))
            goto exit_detach;

      data->hwmon_dev = hwmon_device_register(&client->dev);
      if (IS_ERR(data->hwmon_dev)) {
            err = PTR_ERR(data->hwmon_dev);
            goto exit_remove;
      }

      return 0;

exit_remove:
      sysfs_remove_group(&client->dev.kobj, &data->attrs);
exit_detach:
      i2c_detach_client(client);
exit_free:
      kfree(data);
exit:
      return err;
}

static int ad7418_detach_client(struct i2c_client *client)
{
      struct ad7418_data *data = i2c_get_clientdata(client);
      hwmon_device_unregister(data->hwmon_dev);
      sysfs_remove_group(&client->dev.kobj, &data->attrs);
      i2c_detach_client(client);
      kfree(data);
      return 0;
}

static int __init ad7418_init(void)
{
      return i2c_add_driver(&ad7418_driver);
}

static void __exit ad7418_exit(void)
{
      i2c_del_driver(&ad7418_driver);
}

MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("AD7416/17/18 driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);

module_init(ad7418_init);
module_exit(ad7418_exit);

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