* Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
* the help of Jean Delvare <khali@linux-fr.org>
*
+ * 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 and DS1721 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
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
-#include "lm75.h"
+#include <linux/kernel.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
+/* Supported devices */
+enum chips { ds1621, ds1625, ds1721 };
+
/* Insmod parameters */
static int polarity = -1;
module_param(polarity, int, 0);
MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
-/* Many DS1621 constants specified below */
-/* Config register used for detection */
-/* 7 6 5 4 3 2 1 0 */
-/* |Done|THF |TLF |NVB | X | X |POL |1SHOT| */
+/*
+ * 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|
+ *
+ * - 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
-/* The DS1621 registers */
+#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 */
+ 750, /* 12-bits (0.0625, 750, RES[0..1] = 3 */
+};
+
+#define DS1621_CONVERSION_MAX 750
+#define DS1625_CONVERSION_MAX 500
+
+#define DS1621_TEMP_MAX 125000
+#define DS1621_TEMP_MIN (-55000)
+
+/* The DS1621 temperature registers */
static const u8 DS1621_REG_TEMP[3] = {
0xAA, /* input, word, RO */
0xA2, /* min, word, RW */
};
#define DS1621_REG_CONF 0xAC /* byte, RW */
#define DS1621_COM_START 0xEE /* no data */
+#define DS1721_COM_START 0x51 /* no data */
#define DS1621_COM_STOP 0x22 /* no data */
/* The DS1621 configuration register */
struct mutex update_lock;
char valid; /* !=0 if following fields are valid */
unsigned long last_updated; /* In jiffies */
+ enum chips kind; /* device type */
u16 temp[3]; /* Register values, word */
u8 conf; /* Register encoding, combined */
+ u16 update_interval; /* Conversion rate in milliseconds */
};
+static inline int DS1621_TEMP_FROM_REG(u16 reg)
+{
+ return DIV_ROUND_CLOSEST(((s16)reg / 16) * 625, 10);
+}
+
+/*
+ * TEMP: 0.001C/bit (-55C to +125C)
+ * REG:
+ * - 1621, 1625: x = 0.5C
+ * - 1721: x = 0.0625C
+ * Assume highest resolution and let the bits fall where they may..
+ */
+static inline u16 DS1621_TEMP_TO_REG(long temp)
+{
+ int ntemp = clamp_val(temp, DS1621_TEMP_MIN, DS1621_TEMP_MAX);
+ ntemp += (ntemp < 0 ? -31 : 31);
+ ntemp = DIV_ROUND_CLOSEST(ntemp * 10, 625) << 4;
+ return (u16)ntemp;
+}
+
static void ds1621_init_client(struct i2c_client *client)
{
- u8 conf, new_conf;
+ u8 conf, new_conf, sreg, resol;
+ struct ds1621_data *data = i2c_get_clientdata(client);
new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
/* switch to continuous conversion mode */
if (conf != new_conf)
i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);
+ switch (data->kind) {
+ case ds1625:
+ data->update_interval = DS1625_CONVERSION_MAX;
+ sreg = DS1621_COM_START;
+ break;
+ case ds1721:
+ resol = (new_conf & DS1621_REG_CONFIG_RESOL) >>
+ DS1621_REG_CONFIG_RESOL_SHIFT;
+ data->update_interval = ds1721_convrates[resol];
+ sreg = DS1721_COM_START;
+ break;
+ default:
+ data->update_interval = DS1621_CONVERSION_MAX;
+ sreg = DS1621_COM_START;
+ break;
+ }
+
/* start conversion */
- i2c_smbus_write_byte(client, DS1621_COM_START);
+ i2c_smbus_write_byte(client, sreg);
}
static struct ds1621_data *ds1621_update_client(struct device *dev)
mutex_lock(&data->update_lock);
- if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
- || !data->valid) {
+ if (time_after(jiffies, data->last_updated + data->update_interval) ||
+ !data->valid) {
int i;
dev_dbg(&client->dev, "Starting ds1621 update\n");
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ds1621_data *data = ds1621_update_client(dev);
return sprintf(buf, "%d\n",
- LM75_TEMP_FROM_REG(data->temp[attr->index]));
+ DS1621_TEMP_FROM_REG(data->temp[attr->index]));
}
static ssize_t set_temp(struct device *dev, struct device_attribute *da,
return err;
mutex_lock(&data->update_lock);
- data->temp[attr->index] = LM75_TEMP_TO_REG(val);
+ data->temp[attr->index] = DS1621_TEMP_TO_REG(val);
i2c_smbus_write_word_swapped(client, DS1621_REG_TEMP[attr->index],
data->temp[attr->index]);
mutex_unlock(&data->update_lock);
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
+ data->kind = id->driver_data;
+
/* Initialize the DS1621 chip */
ds1621_init_client(client);
}
static const struct i2c_device_id ds1621_id[] = {
- { "ds1621", 0 },
- { "ds1625", 0 },
+ { "ds1621", ds1621 },
+ { "ds1625", ds1625 },
+ { "ds1721", ds1721 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ds1621_id);
projects / users / jedix / linux-maple.git / commitdiff