linux-imx

/*

 *  ds620.c - Support for temperature sensor and thermostat DS620

 *

 *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>

 *

 *  based on ds1621.c by Christian W. Zuckschwerdt  <zany@triq.net>

 *

 *  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.

 *

 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.

 */

​

#include <linux/module.h>

#include <linux/init.h>

#include <linux/slab.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/platform_data/ds620.h>

​

/*

 * Many DS620 constants specified below

 *  15   14   13   12   11   10   09    08

 * |Done|NVB |THF |TLF |R1  |R0  |AUTOC|1SHOT|

 *

 *  07   06   05   04   03   02   01    00

 * |PO2 |PO1 |A2  |A1  |A0  |    |     |     |

 */

#define DS620_REG_CONFIG_DONE       0x8000

#define DS620_REG_CONFIG_NVB        0x4000

#define DS620_REG_CONFIG_THF        0x2000

#define DS620_REG_CONFIG_TLF        0x1000

#define DS620_REG_CONFIG_R1     0x0800

#define DS620_REG_CONFIG_R0     0x0400

#define DS620_REG_CONFIG_AUTOC      0x0200

#define DS620_REG_CONFIG_1SHOT      0x0100

#define DS620_REG_CONFIG_PO2        0x0080

#define DS620_REG_CONFIG_PO1        0x0040

#define DS620_REG_CONFIG_A2     0x0020

#define DS620_REG_CONFIG_A1     0x0010

#define DS620_REG_CONFIG_A0     0x0008

​

/* The DS620 registers */

static const u8 DS620_REG_TEMP[3] = {

    0xAA,           /* input, word, RO */

    0xA2,           /* min, word, RW */

    0xA0,           /* max, word, RW */

};

​

#define DS620_REG_CONF      0xAC    /* word, RW */

#define DS620_COM_START     0x51    /* no data */

#define DS620_COM_STOP      0x22    /* no data */

​

/* Each client has this additional data */

struct ds620_data {

    struct i2c_client *client;

    struct mutex update_lock;

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

    unsigned long last_updated; /* In jiffies */

​

    s16 temp[3];        /* Register values, word */

};

​

static void ds620_init_client(struct i2c_client *client)

{

    struct ds620_platform_data *ds620_info = dev_get_platdata(&client->dev);

    u16 conf, new_conf;

​

    new_conf = conf =

        i2c_smbus_read_word_swapped(client, DS620_REG_CONF);

​

    /* switch to continuous conversion mode */

    new_conf &= ~DS620_REG_CONFIG_1SHOT;

    /* already high at power-on, but don't trust the BIOS! */

    new_conf |= DS620_REG_CONFIG_PO2;

    /* thermostat mode according to platform data */

    if (ds620_info && ds620_info->pomode == 1)

        new_conf &= ~DS620_REG_CONFIG_PO1; /* PO_LOW */