diff options
Diffstat (limited to 'drivers/hwmon/lm75.c')
| -rw-r--r-- | drivers/hwmon/lm75.c | 445 |
1 files changed, 445 insertions, 0 deletions
diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c new file mode 100644 index 00000000..a83f206a --- /dev/null +++ b/drivers/hwmon/lm75.c @@ -0,0 +1,445 @@ +/* + * 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. + */ + +enum lm75_type { /* keep sorted in alphabetical order */ + adt75, + ds1775, + ds75, + lm75, + lm75a, + max6625, + max6626, + mcp980x, + stds75, + tcn75, + tmp100, + tmp101, + tmp105, + tmp175, + tmp275, + tmp75, +}; + +/* Addresses scanned */ +static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, + 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; + + +/* 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); + + if (IS_ERR(data)) + return PTR_ERR(data); + + 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; + int error; + + error = kstrtol(buf, 10, &temp); + if (error) + return error; + + 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", + dev_name(data->hwmon_dev), client->name); + + return 0; + +exit_remove: + sysfs_remove_group(&client->dev.kobj, &lm75_group); +exit_free: + 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); + kfree(data); + return 0; +} + +static const struct i2c_device_id lm75_ids[] = { + { "adt75", adt75, }, + { "ds1775", ds1775, }, + { "ds75", ds75, }, + { "lm75", lm75, }, + { "lm75a", lm75a, }, + { "max6625", max6625, }, + { "max6626", max6626, }, + { "mcp980x", mcp980x, }, + { "stds75", stds75, }, + { "tcn75", tcn75, }, + { "tmp100", tmp100, }, + { "tmp101", tmp101, }, + { "tmp105", tmp105, }, + { "tmp175", tmp175, }, + { "tmp275", tmp275, }, + { "tmp75", tmp75, }, + { /* LIST END */ } +}; +MODULE_DEVICE_TABLE(i2c, lm75_ids); + +#define LM75A_ID 0xA1 + +/* Return 0 if detection is successful, -ENODEV otherwise */ +static int lm75_detect(struct i2c_client *new_client, + struct i2c_board_info *info) +{ + struct i2c_adapter *adapter = new_client->adapter; + int i; + int conf, hyst, os; + bool is_lm75a = 0; + + 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. + * + * The National Semiconductor LM75A is different than earlier + * LM75s. It has an ID byte of 0xaX (where X is the chip + * revision, with 1 being the only revision in existence) in + * register 7, and unused registers return 0xff rather than the + * last read value. + * + * Note that this function only detects the original National + * Semiconductor LM75 and the LM75A. Clones from other vendors + * aren't detected, on purpose, because they are typically never + * found on PC hardware. They are found on embedded designs where + * they can be instantiated explicitly so detection is not needed. + * The absence of identification registers on all these clones + * would make their exhaustive detection very difficult and weak, + * and odds are that the driver would bind to unsupported devices. + */ + + /* Unused bits */ + conf = i2c_smbus_read_byte_data(new_client, 1); + if (conf & 0xe0) + return -ENODEV; + + /* First check for LM75A */ + if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) { + /* LM75A returns 0xff on unused registers so + just to be sure we check for that too. */ + if (i2c_smbus_read_byte_data(new_client, 4) != 0xff + || i2c_smbus_read_byte_data(new_client, 5) != 0xff + || i2c_smbus_read_byte_data(new_client, 6) != 0xff) + return -ENODEV; + is_lm75a = 1; + hyst = i2c_smbus_read_byte_data(new_client, 2); + os = i2c_smbus_read_byte_data(new_client, 3); + } else { /* Traditional style LM75 detection */ + /* Unused addresses */ + hyst = i2c_smbus_read_byte_data(new_client, 2); + if (i2c_smbus_read_byte_data(new_client, 4) != hyst + || i2c_smbus_read_byte_data(new_client, 5) != hyst + || i2c_smbus_read_byte_data(new_client, 6) != hyst + || i2c_smbus_read_byte_data(new_client, 7) != hyst) + return -ENODEV; + os = i2c_smbus_read_byte_data(new_client, 3); + if (i2c_smbus_read_byte_data(new_client, 4) != os + || i2c_smbus_read_byte_data(new_client, 5) != os + || i2c_smbus_read_byte_data(new_client, 6) != os + || i2c_smbus_read_byte_data(new_client, 7) != os) + return -ENODEV; + } + + /* Addresses cycling */ + for (i = 8; i <= 248; i += 40) { + if (i2c_smbus_read_byte_data(new_client, i + 1) != conf + || i2c_smbus_read_byte_data(new_client, i + 2) != hyst + || i2c_smbus_read_byte_data(new_client, i + 3) != os) + return -ENODEV; + if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7) + != LM75A_ID) + return -ENODEV; + } + + strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE); + + return 0; +} + +#ifdef CONFIG_PM +static int lm75_suspend(struct device *dev) +{ + int status; + struct i2c_client *client = to_i2c_client(dev); + status = lm75_read_value(client, LM75_REG_CONF); + if (status < 0) { + dev_dbg(&client->dev, "Can't read config? %d\n", status); + return status; + } + status = status | LM75_SHUTDOWN; + lm75_write_value(client, LM75_REG_CONF, status); + return 0; +} + +static int lm75_resume(struct device *dev) +{ + int status; + struct i2c_client *client = to_i2c_client(dev); + status = lm75_read_value(client, LM75_REG_CONF); + if (status < 0) { + dev_dbg(&client->dev, "Can't read config? %d\n", status); + return status; + } + status = status & ~LM75_SHUTDOWN; + lm75_write_value(client, LM75_REG_CONF, status); + return 0; +} + +static const struct dev_pm_ops lm75_dev_pm_ops = { + .suspend = lm75_suspend, + .resume = lm75_resume, +}; +#define LM75_DEV_PM_OPS (&lm75_dev_pm_ops) +#else +#define LM75_DEV_PM_OPS NULL +#endif /* CONFIG_PM */ + +static struct i2c_driver lm75_driver = { + .class = I2C_CLASS_HWMON, + .driver = { + .name = "lm75", + .pm = LM75_DEV_PM_OPS, + }, + .probe = lm75_probe, + .remove = lm75_remove, + .id_table = lm75_ids, + .detect = lm75_detect, + .address_list = normal_i2c, +}; + +/*-----------------------------------------------------------------------*/ + +/* 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) +{ + if (reg == LM75_REG_CONF) + return i2c_smbus_read_byte_data(client, reg); + else + return i2c_smbus_read_word_swapped(client, reg); +} + +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_swapped(client, reg, 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); + struct lm75_data *ret = data; + + 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 (unlikely(status < 0)) { + dev_dbg(dev, + "LM75: Failed to read value: reg %d, error %d\n", + LM75_REG_TEMP[i], status); + ret = ERR_PTR(status); + data->valid = 0; + goto abort; + } + data->temp[i] = status; + } + data->last_updated = jiffies; + data->valid = 1; + } + +abort: + mutex_unlock(&data->update_lock); + return ret; +} + +module_i2c_driver(lm75_driver); + +MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); +MODULE_DESCRIPTION("LM75 driver"); +MODULE_LICENSE("GPL"); |