322 lines
9.2 KiB
C
322 lines
9.2 KiB
C
/*
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lm75.c - Part of lm_sensors, Linux kernel modules for hardware
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monitoring
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Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/jiffies.h>
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#include <linux/i2c.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/err.h>
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#include <linux/mutex.h>
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#include "lm75.h"
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/* Addresses to scan */
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static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
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0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
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/* Insmod parameters */
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I2C_CLIENT_INSMOD_1(lm75);
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/* Many LM75 constants specified below */
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/* The LM75 registers */
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#define LM75_REG_CONF 0x01
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static const u8 LM75_REG_TEMP[3] = {
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0x00, /* input */
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0x03, /* max */
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0x02, /* hyst */
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};
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/* Each client has this additional data */
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struct lm75_data {
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struct i2c_client client;
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struct device *hwmon_dev;
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struct mutex update_lock;
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char valid; /* !=0 if following fields are valid */
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unsigned long last_updated; /* In jiffies */
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u16 temp[3]; /* Register values,
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0 = input
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1 = max
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2 = hyst */
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};
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static int lm75_attach_adapter(struct i2c_adapter *adapter);
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static int lm75_detect(struct i2c_adapter *adapter, int address, int kind);
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static void lm75_init_client(struct i2c_client *client);
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static int lm75_detach_client(struct i2c_client *client);
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static int lm75_read_value(struct i2c_client *client, u8 reg);
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static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
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static struct lm75_data *lm75_update_device(struct device *dev);
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/* This is the driver that will be inserted */
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static struct i2c_driver lm75_driver = {
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.driver = {
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.name = "lm75",
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},
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.id = I2C_DRIVERID_LM75,
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.attach_adapter = lm75_attach_adapter,
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.detach_client = lm75_detach_client,
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};
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static ssize_t show_temp(struct device *dev, struct device_attribute *da,
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char *buf)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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struct lm75_data *data = lm75_update_device(dev);
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return sprintf(buf, "%d\n",
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LM75_TEMP_FROM_REG(data->temp[attr->index]));
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}
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static ssize_t set_temp(struct device *dev, struct device_attribute *da,
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const char *buf, size_t count)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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struct i2c_client *client = to_i2c_client(dev);
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struct lm75_data *data = i2c_get_clientdata(client);
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int nr = attr->index;
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long temp = simple_strtol(buf, NULL, 10);
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mutex_lock(&data->update_lock);
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data->temp[nr] = LM75_TEMP_TO_REG(temp);
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lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
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mutex_unlock(&data->update_lock);
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return count;
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}
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static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
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show_temp, set_temp, 1);
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static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
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show_temp, set_temp, 2);
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static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
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static int lm75_attach_adapter(struct i2c_adapter *adapter)
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{
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if (!(adapter->class & I2C_CLASS_HWMON))
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return 0;
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return i2c_probe(adapter, &addr_data, lm75_detect);
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}
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static struct attribute *lm75_attributes[] = {
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&sensor_dev_attr_temp1_input.dev_attr.attr,
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&sensor_dev_attr_temp1_max.dev_attr.attr,
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&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
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NULL
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};
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static const struct attribute_group lm75_group = {
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.attrs = lm75_attributes,
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};
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/* This function is called by i2c_probe */
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static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
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{
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int i;
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struct i2c_client *new_client;
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struct lm75_data *data;
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int err = 0;
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const char *name = "";
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
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I2C_FUNC_SMBUS_WORD_DATA))
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goto exit;
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/* OK. For now, we presume we have a valid client. We now create the
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client structure, even though we cannot fill it completely yet.
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But it allows us to access lm75_{read,write}_value. */
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if (!(data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL))) {
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err = -ENOMEM;
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goto exit;
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}
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new_client = &data->client;
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i2c_set_clientdata(new_client, data);
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new_client->addr = address;
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new_client->adapter = adapter;
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new_client->driver = &lm75_driver;
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new_client->flags = 0;
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/* Now, we do the remaining detection. There is no identification-
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dedicated register so we have to rely on several tricks:
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unused bits, registers cycling over 8-address boundaries,
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addresses 0x04-0x07 returning the last read value.
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The cycling+unused addresses combination is not tested,
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since it would significantly slow the detection down and would
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hardly add any value. */
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if (kind < 0) {
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int cur, conf, hyst, os;
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/* Unused addresses */
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cur = i2c_smbus_read_word_data(new_client, 0);
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conf = i2c_smbus_read_byte_data(new_client, 1);
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hyst = i2c_smbus_read_word_data(new_client, 2);
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if (i2c_smbus_read_word_data(new_client, 4) != hyst
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|| i2c_smbus_read_word_data(new_client, 5) != hyst
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|| i2c_smbus_read_word_data(new_client, 6) != hyst
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|| i2c_smbus_read_word_data(new_client, 7) != hyst)
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goto exit_free;
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os = i2c_smbus_read_word_data(new_client, 3);
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if (i2c_smbus_read_word_data(new_client, 4) != os
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|| i2c_smbus_read_word_data(new_client, 5) != os
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|| i2c_smbus_read_word_data(new_client, 6) != os
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|| i2c_smbus_read_word_data(new_client, 7) != os)
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goto exit_free;
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/* Unused bits */
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if (conf & 0xe0)
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goto exit_free;
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/* Addresses cycling */
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for (i = 8; i < 0xff; i += 8)
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if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
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|| i2c_smbus_read_word_data(new_client, i + 2) != hyst
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|| i2c_smbus_read_word_data(new_client, i + 3) != os)
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goto exit_free;
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}
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/* Determine the chip type - only one kind supported! */
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if (kind <= 0)
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kind = lm75;
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if (kind == lm75) {
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name = "lm75";
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}
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/* Fill in the remaining client fields and put it into the global list */
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strlcpy(new_client->name, name, I2C_NAME_SIZE);
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data->valid = 0;
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mutex_init(&data->update_lock);
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/* Tell the I2C layer a new client has arrived */
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if ((err = i2c_attach_client(new_client)))
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goto exit_free;
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/* Initialize the LM75 chip */
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lm75_init_client(new_client);
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/* Register sysfs hooks */
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if ((err = sysfs_create_group(&new_client->dev.kobj, &lm75_group)))
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goto exit_detach;
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data->hwmon_dev = hwmon_device_register(&new_client->dev);
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if (IS_ERR(data->hwmon_dev)) {
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err = PTR_ERR(data->hwmon_dev);
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goto exit_remove;
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}
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return 0;
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exit_remove:
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sysfs_remove_group(&new_client->dev.kobj, &lm75_group);
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exit_detach:
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i2c_detach_client(new_client);
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exit_free:
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kfree(data);
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exit:
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return err;
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}
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static int lm75_detach_client(struct i2c_client *client)
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{
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struct lm75_data *data = i2c_get_clientdata(client);
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hwmon_device_unregister(data->hwmon_dev);
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sysfs_remove_group(&client->dev.kobj, &lm75_group);
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i2c_detach_client(client);
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kfree(data);
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return 0;
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}
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/* All registers are word-sized, except for the configuration register.
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LM75 uses a high-byte first convention, which is exactly opposite to
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the usual practice. */
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static int lm75_read_value(struct i2c_client *client, u8 reg)
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{
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if (reg == LM75_REG_CONF)
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return i2c_smbus_read_byte_data(client, reg);
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else
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return swab16(i2c_smbus_read_word_data(client, reg));
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}
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/* All registers are word-sized, except for the configuration register.
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LM75 uses a high-byte first convention, which is exactly opposite to
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the usual practice. */
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static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
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{
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if (reg == LM75_REG_CONF)
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return i2c_smbus_write_byte_data(client, reg, value);
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else
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return i2c_smbus_write_word_data(client, reg, swab16(value));
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}
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static void lm75_init_client(struct i2c_client *client)
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{
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int reg;
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/* Enable if in shutdown mode */
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reg = lm75_read_value(client, LM75_REG_CONF);
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if (reg >= 0 && (reg & 0x01))
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lm75_write_value(client, LM75_REG_CONF, reg & 0xfe);
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}
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static struct lm75_data *lm75_update_device(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct lm75_data *data = i2c_get_clientdata(client);
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mutex_lock(&data->update_lock);
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if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
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|| !data->valid) {
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int i;
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dev_dbg(&client->dev, "Starting lm75 update\n");
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for (i = 0; i < ARRAY_SIZE(data->temp); i++)
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data->temp[i] = lm75_read_value(client,
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LM75_REG_TEMP[i]);
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data->last_updated = jiffies;
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data->valid = 1;
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}
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mutex_unlock(&data->update_lock);
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return data;
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}
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static int __init sensors_lm75_init(void)
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{
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return i2c_add_driver(&lm75_driver);
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}
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static void __exit sensors_lm75_exit(void)
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{
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i2c_del_driver(&lm75_driver);
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}
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MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
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MODULE_DESCRIPTION("LM75 driver");
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MODULE_LICENSE("GPL");
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module_init(sensors_lm75_init);
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module_exit(sensors_lm75_exit);
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