summaryrefslogtreecommitdiffstats
path: root/drivers/hwmon/lm75.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/hwmon/lm75.c')
-rw-r--r--drivers/hwmon/lm75.c381
1 files changed, 381 insertions, 0 deletions
diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
new file mode 100644
index 0000000..8f9595f
--- /dev/null
+++ b/drivers/hwmon/lm75.c
@@ -0,0 +1,381 @@
+/*
+ lm75.c - Part of lm_sensors, Linux kernel modules for hardware
+ monitoring
+ Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
+
+ 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 "lm75.h"
+
+
+/*
+ * This driver handles the LM75 and compatible digital temperature sensors.
+ * Only types which are _not_ listed in I2C_CLIENT_INSMOD_*() need to be
+ * listed here. We start at 9 since I2C_CLIENT_INSMOD_*() currently allow
+ * definition of up to 8 chip types (plus zero).
+ */
+
+enum lm75_type { /* keep sorted in alphabetical order */
+ ds1775 = 9,
+ ds75,
+ /* lm75 -- in I2C_CLIENT_INSMOD_1() */
+ lm75a,
+ max6625,
+ max6626,
+ mcp980x,
+ stds75,
+ tcn75,
+ tmp100,
+ tmp101,
+ tmp175,
+ tmp275,
+ tmp75,
+};
+
+/* Addresses scanned */
+static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
+ 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD_1(lm75);
+
+
+/* The LM75 registers */
+#define LM75_REG_CONF 0x01
+static const u8 LM75_REG_TEMP[3] = {
+ 0x00, /* input */
+ 0x03, /* max */
+ 0x02, /* hyst */
+};
+
+/* Each client has this additional data */
+struct lm75_data {
+ struct device *hwmon_dev;
+ struct mutex update_lock;
+ u8 orig_conf;
+ char valid; /* !=0 if registers are valid */
+ unsigned long last_updated; /* In jiffies */
+ u16 temp[3]; /* Register values,
+ 0 = input
+ 1 = max
+ 2 = hyst */
+};
+
+static int lm75_read_value(struct i2c_client *client, u8 reg);
+static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
+static struct lm75_data *lm75_update_device(struct device *dev);
+
+
+/*-----------------------------------------------------------------------*/
+
+/* sysfs attributes for hwmon */
+
+static ssize_t show_temp(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ struct lm75_data *data = lm75_update_device(dev);
+ return sprintf(buf, "%d\n",
+ LM75_TEMP_FROM_REG(data->temp[attr->index]));
+}
+
+static ssize_t set_temp(struct device *dev, struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ struct i2c_client *client = to_i2c_client(dev);
+ struct lm75_data *data = i2c_get_clientdata(client);
+ int nr = attr->index;
+ long temp = simple_strtol(buf, NULL, 10);
+
+ mutex_lock(&data->update_lock);
+ data->temp[nr] = LM75_TEMP_TO_REG(temp);
+ lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
+ mutex_unlock(&data->update_lock);
+ return count;
+}
+
+static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
+ show_temp, set_temp, 1);
+static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
+ show_temp, set_temp, 2);
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
+
+static struct attribute *lm75_attributes[] = {
+ &sensor_dev_attr_temp1_input.dev_attr.attr,
+ &sensor_dev_attr_temp1_max.dev_attr.attr,
+ &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
+
+ NULL
+};
+
+static const struct attribute_group lm75_group = {
+ .attrs = lm75_attributes,
+};
+
+/*-----------------------------------------------------------------------*/
+
+/* device probe and removal */
+
+static int
+lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+ struct lm75_data *data;
+ int status;
+ u8 set_mask, clr_mask;
+ int new;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
+ return -EIO;
+
+ data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, data);
+ mutex_init(&data->update_lock);
+
+ /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
+ * Then tweak to be more precise when appropriate.
+ */
+ set_mask = 0;
+ clr_mask = (1 << 0) /* continuous conversions */
+ | (1 << 6) | (1 << 5); /* 9-bit mode */
+
+ /* configure as specified */
+ status = lm75_read_value(client, LM75_REG_CONF);
+ if (status < 0) {
+ dev_dbg(&client->dev, "Can't read config? %d\n", status);
+ goto exit_free;
+ }
+ data->orig_conf = status;
+ new = status & ~clr_mask;
+ new |= set_mask;
+ if (status != new)
+ lm75_write_value(client, LM75_REG_CONF, new);
+ dev_dbg(&client->dev, "Config %02x\n", new);
+
+ /* Register sysfs hooks */
+ status = sysfs_create_group(&client->dev.kobj, &lm75_group);
+ if (status)
+ goto exit_free;
+
+ data->hwmon_dev = hwmon_device_register(&client->dev);
+ if (IS_ERR(data->hwmon_dev)) {
+ status = PTR_ERR(data->hwmon_dev);
+ goto exit_remove;
+ }
+
+ dev_info(&client->dev, "%s: sensor '%s'\n",
+ data->hwmon_dev->bus_id, client->name);
+
+ return 0;
+
+exit_remove:
+ sysfs_remove_group(&client->dev.kobj, &lm75_group);
+exit_free:
+ i2c_set_clientdata(client, NULL);
+ kfree(data);
+ return status;
+}
+
+static int lm75_remove(struct i2c_client *client)
+{
+ struct lm75_data *data = i2c_get_clientdata(client);
+
+ hwmon_device_unregister(data->hwmon_dev);
+ sysfs_remove_group(&client->dev.kobj, &lm75_group);
+ lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
+ i2c_set_clientdata(client, NULL);
+ kfree(data);
+ return 0;
+}
+
+static const struct i2c_device_id lm75_ids[] = {
+ { "ds1775", ds1775, },
+ { "ds75", ds75, },
+ { "lm75", lm75, },
+ { "lm75a", lm75a, },
+ { "max6625", max6625, },
+ { "max6626", max6626, },
+ { "mcp980x", mcp980x, },
+ { "stds75", stds75, },
+ { "tcn75", tcn75, },
+ { "tmp100", tmp100, },
+ { "tmp101", tmp101, },
+ { "tmp175", tmp175, },
+ { "tmp275", tmp275, },
+ { "tmp75", tmp75, },
+ { /* LIST END */ }
+};
+MODULE_DEVICE_TABLE(i2c, lm75_ids);
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int lm75_detect(struct i2c_client *new_client, int kind,
+ struct i2c_board_info *info)
+{
+ struct i2c_adapter *adapter = new_client->adapter;
+ int i;
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+ I2C_FUNC_SMBUS_WORD_DATA))
+ return -ENODEV;
+
+ /* Now, we do the remaining detection. There is no identification-
+ dedicated register so we have to rely on several tricks:
+ unused bits, registers cycling over 8-address boundaries,
+ addresses 0x04-0x07 returning the last read value.
+ The cycling+unused addresses combination is not tested,
+ since it would significantly slow the detection down and would
+ hardly add any value. */
+ if (kind < 0) {
+ int cur, conf, hyst, os;
+
+ /* Unused addresses */
+ cur = i2c_smbus_read_word_data(new_client, 0);
+ conf = i2c_smbus_read_byte_data(new_client, 1);
+ hyst = i2c_smbus_read_word_data(new_client, 2);
+ if (i2c_smbus_read_word_data(new_client, 4) != hyst
+ || i2c_smbus_read_word_data(new_client, 5) != hyst
+ || i2c_smbus_read_word_data(new_client, 6) != hyst
+ || i2c_smbus_read_word_data(new_client, 7) != hyst)
+ return -ENODEV;
+ os = i2c_smbus_read_word_data(new_client, 3);
+ if (i2c_smbus_read_word_data(new_client, 4) != os
+ || i2c_smbus_read_word_data(new_client, 5) != os
+ || i2c_smbus_read_word_data(new_client, 6) != os
+ || i2c_smbus_read_word_data(new_client, 7) != os)
+ return -ENODEV;
+
+ /* Unused bits */
+ if (conf & 0xe0)
+ return -ENODEV;
+
+ /* Addresses cycling */
+ for (i = 8; i < 0xff; i += 8)
+ if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
+ || i2c_smbus_read_word_data(new_client, i + 2) != hyst
+ || i2c_smbus_read_word_data(new_client, i + 3) != os)
+ return -ENODEV;
+ }
+
+ /* NOTE: we treat "force=..." and "force_lm75=..." the same.
+ * Only new-style driver binding distinguishes chip types.
+ */
+ strlcpy(info->type, "lm75", I2C_NAME_SIZE);
+
+ return 0;
+}
+
+static struct i2c_driver lm75_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "lm75",
+ },
+ .probe = lm75_probe,
+ .remove = lm75_remove,
+ .id_table = lm75_ids,
+ .detect = lm75_detect,
+ .address_data = &addr_data,
+};
+
+/*-----------------------------------------------------------------------*/
+
+/* register access */
+
+/* All registers are word-sized, except for the configuration register.
+ LM75 uses a high-byte first convention, which is exactly opposite to
+ the SMBus standard. */
+static int lm75_read_value(struct i2c_client *client, u8 reg)
+{
+ int value;
+
+ if (reg == LM75_REG_CONF)
+ return i2c_smbus_read_byte_data(client, reg);
+
+ value = i2c_smbus_read_word_data(client, reg);
+ return (value < 0) ? value : swab16(value);
+}
+
+static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
+{
+ if (reg == LM75_REG_CONF)
+ return i2c_smbus_write_byte_data(client, reg, value);
+ else
+ return i2c_smbus_write_word_data(client, reg, swab16(value));
+}
+
+static struct lm75_data *lm75_update_device(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct lm75_data *data = i2c_get_clientdata(client);
+
+ mutex_lock(&data->update_lock);
+
+ if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
+ || !data->valid) {
+ int i;
+ dev_dbg(&client->dev, "Starting lm75 update\n");
+
+ for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
+ int status;
+
+ status = lm75_read_value(client, LM75_REG_TEMP[i]);
+ if (status < 0)
+ dev_dbg(&client->dev, "reg %d, err %d\n",
+ LM75_REG_TEMP[i], status);
+ else
+ data->temp[i] = status;
+ }
+ data->last_updated = jiffies;
+ data->valid = 1;
+ }
+
+ mutex_unlock(&data->update_lock);
+
+ return data;
+}
+
+/*-----------------------------------------------------------------------*/
+
+/* module glue */
+
+static int __init sensors_lm75_init(void)
+{
+ return i2c_add_driver(&lm75_driver);
+}
+
+static void __exit sensors_lm75_exit(void)
+{
+ i2c_del_driver(&lm75_driver);
+}
+
+MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
+MODULE_DESCRIPTION("LM75 driver");
+MODULE_LICENSE("GPL");
+
+module_init(sensors_lm75_init);
+module_exit(sensors_lm75_exit);
OpenPOWER on IntegriCloud