linux-imx

/*

 * An hwmon driver for the Analog Devices AD7414

 *

 * Copyright 2006 Stefan Roese <sr at denx.de>, DENX Software Engineering

 *

 * Copyright (c) 2008 PIKA Technologies

 *   Sean MacLennan <smaclennan@pikatech.com>

 *

 * Copyright (c) 2008 Spansion Inc.

 *   Frank Edelhaeuser <frank.edelhaeuser at spansion.com>

 *   (converted to "new style" I2C driver model, removed checkpatch.pl warnings)

 *

 * Based on ad7418.c

 * Copyright 2006 Tower Technologies, Alessandro Zummo <a.zummo at towertech.it>

 *

 * 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/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/sysfs.h>

#include <linux/slab.h>

​

​

/* AD7414 registers */

#define AD7414_REG_TEMP     0x00

#define AD7414_REG_CONF     0x01

#define AD7414_REG_T_HIGH   0x02

#define AD7414_REG_T_LOW    0x03

​

static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW };

​

struct ad7414_data {

    struct i2c_client   *client;

    struct mutex        lock;   /* atomic read data updates */

    char            valid;  /* !=0 if following fields are valid */

    unsigned long       next_update;    /* In jiffies */

    s16         temp_input; /* Register values */

    s8          temps[ARRAY_SIZE(AD7414_REG_LIMIT)];

};

​

/* REG: (0.25C/bit, two's complement) << 6 */

static inline int ad7414_temp_from_reg(s16 reg)

{

    /*

     * use integer division instead of equivalent right shift to

     * guarantee arithmetic shift and preserve the sign

     */

    return ((int)reg / 64) * 250;

}

​

static inline int ad7414_read(struct i2c_client *client, u8 reg)

{

    if (reg == AD7414_REG_TEMP)

        return i2c_smbus_read_word_swapped(client, reg);

    else

        return i2c_smbus_read_byte_data(client, reg);

}

​

static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value)

{

    return i2c_smbus_write_byte_data(client, reg, value);

}

​

static struct ad7414_data *ad7414_update_device(struct device *dev)

{

    struct ad7414_data *data = dev_get_drvdata(dev);

    struct i2c_client *client = data->client;

​

    mutex_lock(&data->lock);

​

    if (time_after(jiffies, data->next_update) || !data->valid) {

        int value, i;

​

        dev_dbg(&client->dev, "starting ad7414 update\n");

​

        value = ad7414_read(client, AD7414_REG_TEMP);

        if (value < 0)

            dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n",

                value);

        else

            data->temp_input = value;

​

        for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) {