diff options
Diffstat (limited to 'drivers/i2c/chips/lm92.c')
| -rw-r--r-- | drivers/i2c/chips/lm92.c | 429 |
1 files changed, 429 insertions, 0 deletions
diff --git a/drivers/i2c/chips/lm92.c b/drivers/i2c/chips/lm92.c new file mode 100644 index 00000000000..fe6e83d70a7 --- /dev/null +++ b/drivers/i2c/chips/lm92.c @@ -0,0 +1,429 @@ +/* + * lm92 - Hardware monitoring driver + * Copyright (C) 2005 Jean Delvare <khali@linux-fr.org> + * + * Based on the lm90 driver, with some ideas taken from the lm_sensors + * lm92 driver as well. + * + * The LM92 is a sensor chip made by National Semiconductor. It reports + * its own temperature with a 0.0625 deg resolution and a 0.33 deg + * accuracy. Complete datasheet can be obtained from National's website + * at: + * http://www.national.com/pf/LM/LM92.html + * + * This driver also supports the MAX6635 sensor chip made by Maxim. + * This chip is compatible with the LM92, but has a lesser accuracy + * (1.0 deg). Complete datasheet can be obtained from Maxim's website + * at: + * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074 + * + * Since the LM92 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. + * + * Support could easily be added for the National Semiconductor LM76 + * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible + * with the LM92. + * + * 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/i2c.h> +#include <linux/i2c-sensor.h> + + +/* The LM92 and MAX6635 have 2 two-state pins for address selection, + resulting in 4 possible addresses. */ +static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, + I2C_CLIENT_END }; +static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END }; + +/* Insmod parameters */ +SENSORS_INSMOD_1(lm92); + +/* The LM92 registers */ +#define LM92_REG_CONFIG 0x01 /* 8-bit, RW */ +#define LM92_REG_TEMP 0x00 /* 16-bit, RO */ +#define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */ +#define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */ +#define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */ +#define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */ +#define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */ + +/* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius, + left-justified in 16-bit registers. No rounding is done, with such + a resolution it's just not worth it. Note that the MAX6635 doesn't + make use of the 4 lower bits for limits (i.e. effective resolution + for limits is 1 degree Celsius). */ +static inline int TEMP_FROM_REG(s16 reg) +{ + return reg / 8 * 625 / 10; +} + +static inline s16 TEMP_TO_REG(int val) +{ + if (val <= -60000) + return -60000 * 10 / 625 * 8; + if (val >= 160000) + return 160000 * 10 / 625 * 8; + return val * 10 / 625 * 8; +} + +/* Alarm flags are stored in the 3 LSB of the temperature register */ +static inline u8 ALARMS_FROM_REG(s16 reg) +{ + return reg & 0x0007; +} + +/* Driver data (common to all clients) */ +static struct i2c_driver lm92_driver; + +/* Client data (each client gets its own) */ +struct lm92_data { + struct i2c_client client; + struct semaphore update_lock; + char valid; /* zero until following fields are valid */ + unsigned long last_updated; /* in jiffies */ + + /* registers values */ + s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst; +}; + + +/* + * Sysfs attributes and callback functions + */ + +static struct lm92_data *lm92_update_device(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + struct lm92_data *data = i2c_get_clientdata(client); + + down(&data->update_lock); + + if (time_after(jiffies, data->last_updated + HZ) + || !data->valid) { + dev_dbg(&client->dev, "Updating lm92 data\n"); + data->temp1_input = swab16(i2c_smbus_read_word_data(client, + LM92_REG_TEMP)); + data->temp1_hyst = swab16(i2c_smbus_read_word_data(client, + LM92_REG_TEMP_HYST)); + data->temp1_crit = swab16(i2c_smbus_read_word_data(client, + LM92_REG_TEMP_CRIT)); + data->temp1_min = swab16(i2c_smbus_read_word_data(client, + LM92_REG_TEMP_LOW)); + data->temp1_max = swab16(i2c_smbus_read_word_data(client, + LM92_REG_TEMP_HIGH)); + + data->last_updated = jiffies; + data->valid = 1; + } + + up(&data->update_lock); + + return data; +} + +#define show_temp(value) \ +static ssize_t show_##value(struct device *dev, char *buf) \ +{ \ + struct lm92_data *data = lm92_update_device(dev); \ + return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \ +} +show_temp(temp1_input); +show_temp(temp1_crit); +show_temp(temp1_min); +show_temp(temp1_max); + +#define set_temp(value, reg) \ +static ssize_t set_##value(struct device *dev, const char *buf, \ + size_t count) \ +{ \ + struct i2c_client *client = to_i2c_client(dev); \ + struct lm92_data *data = i2c_get_clientdata(client); \ + long val = simple_strtol(buf, NULL, 10); \ + \ + down(&data->update_lock); \ + data->value = TEMP_TO_REG(val); \ + i2c_smbus_write_word_data(client, reg, swab16(data->value)); \ + up(&data->update_lock); \ + return count; \ +} +set_temp(temp1_crit, LM92_REG_TEMP_CRIT); +set_temp(temp1_min, LM92_REG_TEMP_LOW); +set_temp(temp1_max, LM92_REG_TEMP_HIGH); + +static ssize_t show_temp1_crit_hyst(struct device *dev, char *buf) +{ + struct lm92_data *data = lm92_update_device(dev); + return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit) + - TEMP_FROM_REG(data->temp1_hyst)); +} +static ssize_t show_temp1_max_hyst(struct device *dev, char *buf) +{ + struct lm92_data *data = lm92_update_device(dev); + return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max) + - TEMP_FROM_REG(data->temp1_hyst)); +} +static ssize_t show_temp1_min_hyst(struct device *dev, char *buf) +{ + struct lm92_data *data = lm92_update_device(dev); + return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min) + + TEMP_FROM_REG(data->temp1_hyst)); +} + +static ssize_t set_temp1_crit_hyst(struct device *dev, const char *buf, + size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct lm92_data *data = i2c_get_clientdata(client); + long val = simple_strtol(buf, NULL, 10); + + down(&data->update_lock); + data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val; + i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST, + swab16(TEMP_TO_REG(data->temp1_hyst))); + up(&data->update_lock); + return count; +} + +static ssize_t show_alarms(struct device *dev, char *buf) +{ + struct lm92_data *data = lm92_update_device(dev); + return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input)); +} + +static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL); +static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit, + set_temp1_crit); +static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst, + set_temp1_crit_hyst); +static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min, + set_temp1_min); +static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL); +static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max, + set_temp1_max); +static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL); +static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); + + +/* + * Detection and registration + */ + +static void lm92_init_client(struct i2c_client *client) +{ + u8 config; + + /* Start the conversions if needed */ + config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); + if (config & 0x01) + i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, + config & 0xFE); +} + +/* The MAX6635 has no identification register, so we have to use tricks + to identify it reliably. This is somewhat slow. + Note that we do NOT rely on the 2 MSB of the configuration register + always reading 0, as suggested by the datasheet, because it was once + reported not to be true. */ +static int max6635_check(struct i2c_client *client) +{ + u16 temp_low, temp_high, temp_hyst, temp_crit; + u8 conf; + int i; + + /* No manufacturer ID register, so a read from this address will + always return the last read value. */ + temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW); + if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low) + return 0; + temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH); + if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high) + return 0; + + /* Limits are stored as integer values (signed, 9-bit). */ + if ((temp_low & 0x7f00) || (temp_high & 0x7f00)) + return 0; + temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST); + temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT); + if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00)) + return 0; + + /* Registers addresses were found to cycle over 16-byte boundaries. + We don't test all registers with all offsets so as to save some + reads and time, but this should still be sufficient to dismiss + non-MAX6635 chips. */ + conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); + for (i=16; i<96; i*=2) { + if (temp_hyst != i2c_smbus_read_word_data(client, + LM92_REG_TEMP_HYST + i - 16) + || temp_crit != i2c_smbus_read_word_data(client, + LM92_REG_TEMP_CRIT + i) + || temp_low != i2c_smbus_read_word_data(client, + LM92_REG_TEMP_LOW + i + 16) + || temp_high != i2c_smbus_read_word_data(client, + LM92_REG_TEMP_HIGH + i + 32) + || conf != i2c_smbus_read_byte_data(client, + LM92_REG_CONFIG + i)) + return 0; + } + + return 1; +} + +/* The following function does more than just detection. If detection + succeeds, it also registers the new chip. */ +static int lm92_detect(struct i2c_adapter *adapter, int address, int kind) +{ + struct i2c_client *new_client; + struct lm92_data *data; + int err = 0; + char *name; + + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA + | I2C_FUNC_SMBUS_WORD_DATA)) + goto exit; + + if (!(data = kmalloc(sizeof(struct lm92_data), GFP_KERNEL))) { + err = -ENOMEM; + goto exit; + } + memset(data, 0, sizeof(struct lm92_data)); + + /* Fill in enough client fields so that we can read from the chip, + which is required for identication */ + new_client = &data->client; + i2c_set_clientdata(new_client, data); + new_client->addr = address; + new_client->adapter = adapter; + new_client->driver = &lm92_driver; + new_client->flags = 0; + + /* A negative kind means that the driver was loaded with no force + parameter (default), so we must identify the chip. */ + if (kind < 0) { + u8 config = i2c_smbus_read_byte_data(new_client, + LM92_REG_CONFIG); + u16 man_id = i2c_smbus_read_word_data(new_client, + LM92_REG_MAN_ID); + + if ((config & 0xe0) == 0x00 + && man_id == 0x0180) { + pr_info("lm92: Found National Semiconductor LM92 chip\n"); + kind = lm92; + } else + if (max6635_check(new_client)) { + pr_info("lm92: Found Maxim MAX6635 chip\n"); + kind = lm92; /* No separate prefix */ + } + else + goto exit_free; + } else + if (kind == 0) /* Default to an LM92 if forced */ + kind = lm92; + + /* Give it the proper name */ + if (kind == lm92) { + name = "lm92"; + } else { /* Supposedly cannot happen */ + dev_dbg(&new_client->dev, "Kind out of range?\n"); + goto exit_free; + } + + /* Fill in the remaining client fields */ + strlcpy(new_client->name, name, I2C_NAME_SIZE); + data->valid = 0; + init_MUTEX(&data->update_lock); + + /* Tell the i2c subsystem a new client has arrived */ + if ((err = i2c_attach_client(new_client))) + goto exit_free; + + /* Initialize the chipset */ + lm92_init_client(new_client); + + /* Register sysfs hooks */ + device_create_file(&new_client->dev, &dev_attr_temp1_input); + device_create_file(&new_client->dev, &dev_attr_temp1_crit); + device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst); + device_create_file(&new_client->dev, &dev_attr_temp1_min); + device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst); + device_create_file(&new_client->dev, &dev_attr_temp1_max); + device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst); + device_create_file(&new_client->dev, &dev_attr_alarms); + + return 0; + +exit_free: + kfree(data); +exit: + return err; +} + +static int lm92_attach_adapter(struct i2c_adapter *adapter) +{ + if (!(adapter->class & I2C_CLASS_HWMON)) + return 0; + return i2c_detect(adapter, &addr_data, lm92_detect); +} + +static int lm92_detach_client(struct i2c_client *client) +{ + int err; + + if ((err = i2c_detach_client(client))) { + dev_err(&client->dev, "Client deregistration failed, " + "client not detached.\n"); + return err; + } + + kfree(i2c_get_clientdata(client)); + return 0; +} + + +/* + * Module and driver stuff + */ + +static struct i2c_driver lm92_driver = { + .owner = THIS_MODULE, + .name = "lm92", + .id = I2C_DRIVERID_LM92, + .flags = I2C_DF_NOTIFY, + .attach_adapter = lm92_attach_adapter, + .detach_client = lm92_detach_client, +}; + +static int __init sensors_lm92_init(void) +{ + return i2c_add_driver(&lm92_driver); +} + +static void __exit sensors_lm92_exit(void) +{ + i2c_del_driver(&lm92_driver); +} + +MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); +MODULE_DESCRIPTION("LM92/MAX6635 driver"); +MODULE_LICENSE("GPL"); + +module_init(sensors_lm92_init); +module_exit(sensors_lm92_exit); |