diff options
Diffstat (limited to 'drivers/hwmon/lm77.c')
| -rw-r--r-- | drivers/hwmon/lm77.c | 361 |
1 files changed, 361 insertions, 0 deletions
diff --git a/drivers/hwmon/lm77.c b/drivers/hwmon/lm77.c new file mode 100644 index 000000000..7570c9d50 --- /dev/null +++ b/drivers/hwmon/lm77.c @@ -0,0 +1,361 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * lm77.c - Part of lm_sensors, Linux kernel modules for hardware + * monitoring + * + * Copyright (c) 2004 Andras BALI <drewie@freemail.hu> + * + * Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. The LM77 + * is a temperature sensor and thermal window comparator with 0.5 deg + * resolution made by National Semiconductor. Complete datasheet can be + * obtained at their site: + * http://www.national.com/pf/LM/LM77.html + */ + +#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> + +/* Addresses to scan */ +static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, + I2C_CLIENT_END }; + +/* The LM77 registers */ +#define LM77_REG_TEMP 0x00 +#define LM77_REG_CONF 0x01 +#define LM77_REG_TEMP_HYST 0x02 +#define LM77_REG_TEMP_CRIT 0x03 +#define LM77_REG_TEMP_MIN 0x04 +#define LM77_REG_TEMP_MAX 0x05 + +enum temp_index { + t_input = 0, + t_crit, + t_min, + t_max, + t_hyst, + t_num_temp +}; + +static const u8 temp_regs[t_num_temp] = { + [t_input] = LM77_REG_TEMP, + [t_min] = LM77_REG_TEMP_MIN, + [t_max] = LM77_REG_TEMP_MAX, + [t_crit] = LM77_REG_TEMP_CRIT, + [t_hyst] = LM77_REG_TEMP_HYST, +}; + +/* Each client has this additional data */ +struct lm77_data { + struct i2c_client *client; + struct mutex update_lock; + char valid; + unsigned long last_updated; /* In jiffies */ + int temp[t_num_temp]; /* index using temp_index */ + u8 alarms; +}; + +/* straight from the datasheet */ +#define LM77_TEMP_MIN (-55000) +#define LM77_TEMP_MAX 125000 + +/* + * In the temperature registers, the low 3 bits are not part of the + * temperature values; they are the status bits. + */ +static inline s16 LM77_TEMP_TO_REG(int temp) +{ + return (temp / 500) * 8; +} + +static inline int LM77_TEMP_FROM_REG(s16 reg) +{ + return (reg / 8) * 500; +} + +/* + * All registers are word-sized, except for the configuration register. + * The LM77 uses the high-byte first convention. + */ +static u16 lm77_read_value(struct i2c_client *client, u8 reg) +{ + if (reg == LM77_REG_CONF) + return i2c_smbus_read_byte_data(client, reg); + else + return i2c_smbus_read_word_swapped(client, reg); +} + +static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) +{ + if (reg == LM77_REG_CONF) + return i2c_smbus_write_byte_data(client, reg, value); + else + return i2c_smbus_write_word_swapped(client, reg, value); +} + +static struct lm77_data *lm77_update_device(struct device *dev) +{ + struct lm77_data *data = dev_get_drvdata(dev); + struct i2c_client *client = data->client; + int i; + + mutex_lock(&data->update_lock); + + if (time_after(jiffies, data->last_updated + HZ + HZ / 2) + || !data->valid) { + dev_dbg(&client->dev, "Starting lm77 update\n"); + for (i = 0; i < t_num_temp; i++) { + data->temp[i] = + LM77_TEMP_FROM_REG(lm77_read_value(client, + temp_regs[i])); + } + data->alarms = + lm77_read_value(client, LM77_REG_TEMP) & 0x0007; + data->last_updated = jiffies; + data->valid = 1; + } + + mutex_unlock(&data->update_lock); + + return data; +} + +/* sysfs stuff */ + +static ssize_t temp_show(struct device *dev, struct device_attribute *devattr, + char *buf) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); + struct lm77_data *data = lm77_update_device(dev); + + return sprintf(buf, "%d\n", data->temp[attr->index]); +} + +static ssize_t temp_hyst_show(struct device *dev, + struct device_attribute *devattr, char *buf) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); + struct lm77_data *data = lm77_update_device(dev); + int nr = attr->index; + int temp; + + temp = nr == t_min ? data->temp[nr] + data->temp[t_hyst] : + data->temp[nr] - data->temp[t_hyst]; + + return sprintf(buf, "%d\n", temp); +} + +static ssize_t temp_store(struct device *dev, + struct device_attribute *devattr, const char *buf, + size_t count) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); + struct lm77_data *data = dev_get_drvdata(dev); + struct i2c_client *client = data->client; + int nr = attr->index; + long val; + int err; + + err = kstrtol(buf, 10, &val); + if (err) + return err; + + val = clamp_val(val, LM77_TEMP_MIN, LM77_TEMP_MAX); + mutex_lock(&data->update_lock); + data->temp[nr] = val; + lm77_write_value(client, temp_regs[nr], LM77_TEMP_TO_REG(val)); + mutex_unlock(&data->update_lock); + return count; +} + +/* + * hysteresis is stored as a relative value on the chip, so it has to be + * converted first. + */ +static ssize_t temp_hyst_store(struct device *dev, + struct device_attribute *devattr, + const char *buf, size_t count) +{ + struct lm77_data *data = dev_get_drvdata(dev); + struct i2c_client *client = data->client; + long val; + int err; + + err = kstrtol(buf, 10, &val); + if (err) + return err; + + mutex_lock(&data->update_lock); + val = clamp_val(data->temp[t_crit] - val, LM77_TEMP_MIN, LM77_TEMP_MAX); + data->temp[t_hyst] = val; + lm77_write_value(client, LM77_REG_TEMP_HYST, + LM77_TEMP_TO_REG(data->temp[t_hyst])); + mutex_unlock(&data->update_lock); + return count; +} + +static ssize_t alarm_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + int bitnr = to_sensor_dev_attr(attr)->index; + struct lm77_data *data = lm77_update_device(dev); + return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1); +} + +static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, t_input); +static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit); +static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min); +static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max); + +static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit); +static SENSOR_DEVICE_ATTR_RO(temp1_min_hyst, temp_hyst, t_min); +static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max); + +static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2); +static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0); +static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 1); + +static struct attribute *lm77_attrs[] = { + &sensor_dev_attr_temp1_input.dev_attr.attr, + &sensor_dev_attr_temp1_crit.dev_attr.attr, + &sensor_dev_attr_temp1_min.dev_attr.attr, + &sensor_dev_attr_temp1_max.dev_attr.attr, + &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr, + &sensor_dev_attr_temp1_min_hyst.dev_attr.attr, + &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, + &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, + &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, + &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, + NULL +}; +ATTRIBUTE_GROUPS(lm77); + +/* Return 0 if detection is successful, -ENODEV otherwise */ +static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info) +{ + struct i2c_adapter *adapter = client->adapter; + int i, cur, conf, hyst, crit, min, max; + + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_WORD_DATA)) + return -ENODEV; + + /* + * Here comes the remaining detection. Since the LM77 has no + * register dedicated to identification, we have to rely on the + * following tricks: + * + * 1. the high 4 bits represent the sign and thus they should + * always be the same + * 2. the high 3 bits are unused in the configuration register + * 3. addresses 0x06 and 0x07 return the last read value + * 4. registers cycling over 8-address boundaries + * + * Word-sized registers are high-byte first. + */ + + /* addresses cycling */ + cur = i2c_smbus_read_word_data(client, 0); + conf = i2c_smbus_read_byte_data(client, 1); + hyst = i2c_smbus_read_word_data(client, 2); + crit = i2c_smbus_read_word_data(client, 3); + min = i2c_smbus_read_word_data(client, 4); + max = i2c_smbus_read_word_data(client, 5); + for (i = 8; i <= 0xff; i += 8) { + if (i2c_smbus_read_byte_data(client, i + 1) != conf + || i2c_smbus_read_word_data(client, i + 2) != hyst + || i2c_smbus_read_word_data(client, i + 3) != crit + || i2c_smbus_read_word_data(client, i + 4) != min + || i2c_smbus_read_word_data(client, i + 5) != max) + return -ENODEV; + } + + /* sign bits */ + if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) + || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) + || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) + || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) + || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) + return -ENODEV; + + /* unused bits */ + if (conf & 0xe0) + return -ENODEV; + + /* 0x06 and 0x07 return the last read value */ + cur = i2c_smbus_read_word_data(client, 0); + if (i2c_smbus_read_word_data(client, 6) != cur + || i2c_smbus_read_word_data(client, 7) != cur) + return -ENODEV; + hyst = i2c_smbus_read_word_data(client, 2); + if (i2c_smbus_read_word_data(client, 6) != hyst + || i2c_smbus_read_word_data(client, 7) != hyst) + return -ENODEV; + min = i2c_smbus_read_word_data(client, 4); + if (i2c_smbus_read_word_data(client, 6) != min + || i2c_smbus_read_word_data(client, 7) != min) + return -ENODEV; + + strlcpy(info->type, "lm77", I2C_NAME_SIZE); + + return 0; +} + +static void lm77_init_client(struct i2c_client *client) +{ + /* Initialize the LM77 chip - turn off shutdown mode */ + int conf = lm77_read_value(client, LM77_REG_CONF); + if (conf & 1) + lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); +} + +static int lm77_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct device *hwmon_dev; + struct lm77_data *data; + + data = devm_kzalloc(dev, sizeof(struct lm77_data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->client = client; + mutex_init(&data->update_lock); + + /* Initialize the LM77 chip */ + lm77_init_client(client); + + hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, + data, lm77_groups); + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +static const struct i2c_device_id lm77_id[] = { + { "lm77", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, lm77_id); + +/* This is the driver that will be inserted */ +static struct i2c_driver lm77_driver = { + .class = I2C_CLASS_HWMON, + .driver = { + .name = "lm77", + }, + .probe_new = lm77_probe, + .id_table = lm77_id, + .detect = lm77_detect, + .address_list = normal_i2c, +}; + +module_i2c_driver(lm77_driver); + +MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); +MODULE_DESCRIPTION("LM77 driver"); +MODULE_LICENSE("GPL"); |