linux-imx

/*

 * ds1621.c - Part of lm_sensors, Linux kernel modules for hardware

 *        monitoring

 * Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23

 * based on lm75.c by Frodo Looijaard <frodol@dds.nl>

 * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with

 * the help of Jean Delvare <jdelvare@suse.de>

 *

 * The DS1621 device is a digital temperature/thermometer with 9-bit

 * resolution, a thermal alarm output (Tout), and user-defined minimum

 * and maximum temperature thresholds (TH and TL).

 *

 * The DS1625, DS1631, DS1721, and DS1731 are pin compatible with the DS1621

 * and similar in operation, with slight variations as noted in the device

 * datasheets (please refer to www.maximintegrated.com for specific

 * device information).

 *

 * Since the DS1621 was the first chipset supported by this driver,

 * most comments will refer to this chipset, but are actually general

 * and concern all supported chipsets, unless mentioned otherwise.

 *

 * 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/kernel.h>

​

/* Supported devices */

enum chips { ds1621, ds1625, ds1631, ds1721, ds1731 };

​

/* Insmod parameters */

static int polarity = -1;

module_param(polarity, int, 0);

MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");

​

/*

 * The Configuration/Status register

 *

 * - DS1621:

 *   7    6    5    4    3    2    1    0

 * |Done|THF |TLF |NVB | X  | X  |POL |1SHOT|

 *

 * - DS1625:

 *   7    6    5    4    3    2    1    0

 * |Done|THF |TLF |NVB | 1  | 0  |POL |1SHOT|

 *

 * - DS1631, DS1731:

 *   7    6    5    4    3    2    1    0

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

 *

 * - DS1721:

 *   7    6    5    4    3    2    1    0

 * |Done| X  | X  | U  | R1 | R0 |POL |1SHOT|

 *

 * Where:

 * - 'X' is Reserved

 * - 'U' is Undefined

 */

#define DS1621_REG_CONFIG_NVB       0x10

#define DS1621_REG_CONFIG_RESOL     0x0C

#define DS1621_REG_CONFIG_POLARITY  0x02

#define DS1621_REG_CONFIG_1SHOT     0x01

#define DS1621_REG_CONFIG_DONE      0x80

​

#define DS1621_REG_CONFIG_RESOL_SHIFT   2

​

/* ds1721 conversion rates: {C/LSB, time(ms), resolution bit setting} */

static const unsigned short ds1721_convrates[] = {

    94, /*  9-bits (0.5,  93.75, RES[0..1] = 0 */

    188,    /* 10-bits (0.25, 187.5, RES[0..1] = 1 */

    375,    /* 11-bits (0.125,  375, RES[0..1] = 2 */