linux-imx

/*

 * Maxim MAX197 A/D Converter driver

 *

 * Copyright (c) 2012 Savoir-faire Linux Inc.

 *          Vivien Didelot <vivien.didelot@savoirfairelinux.com>

 *

 * 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.

 *

 * For further information, see the Documentation/hwmon/max197 file.

 */

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/mod_devicetable.h>

#include <linux/init.h>

#include <linux/err.h>

#include <linux/slab.h>

#include <linux/mutex.h>

#include <linux/device.h>

#include <linux/sysfs.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/platform_device.h>

#include <linux/platform_data/max197.h>

​

#define MAX199_LIMIT    4000        /* 4V */

#define MAX197_LIMIT    10000       /* 10V */

​

#define MAX197_NUM_CH   8       /* 8 Analog Input Channels */

​

/* Control byte format */

#define MAX197_BIP  (1 << 3)    /* Bipolarity */

#define MAX197_RNG  (1 << 4)    /* Full range */

​

#define MAX197_SCALE    12207       /* Scale coefficient for raw data */

​

/* List of supported chips */

enum max197_chips { max197, max199 };

​

/**

 * struct max197_data - device instance specific data

 * @pdata:      Platform data.

 * @hwmon_dev:      The hwmon device.

 * @lock:       Read/Write mutex.

 * @limit:      Max range value (10V for MAX197, 4V for MAX199).

 * @scale:      Need to scale.

 * @ctrl_bytes:     Channels control byte.

 */

struct max197_data {

    struct max197_platform_data *pdata;

    struct device *hwmon_dev;

    struct mutex lock;

    int limit;

    bool scale;

    u8 ctrl_bytes[MAX197_NUM_CH];

};

​

static inline void max197_set_unipolarity(struct max197_data *data, int channel)

{

    data->ctrl_bytes[channel] &= ~MAX197_BIP;

}

​

static inline void max197_set_bipolarity(struct max197_data *data, int channel)

{

    data->ctrl_bytes[channel] |= MAX197_BIP;

}

​

static inline void max197_set_half_range(struct max197_data *data, int channel)

{

    data->ctrl_bytes[channel] &= ~MAX197_RNG;

}

​

static inline void max197_set_full_range(struct max197_data *data, int channel)

{

    data->ctrl_bytes[channel] |= MAX197_RNG;

}

​

static inline bool max197_is_bipolar(struct max197_data *data, int channel)

{

    return data->ctrl_bytes[channel] & MAX197_BIP;

}

​

static inline bool max197_is_full_range(struct max197_data *data, int channel)

{

    return data->ctrl_bytes[channel] & MAX197_RNG;

}

​

/* Function called on read access on in{0,1,2,3,4,5,6,7}_{min,max} */

static ssize_t max197_show_range(struct device *dev,

                 struct device_attribute *devattr, char *buf)