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361 lines
9.9 KiB
361 lines
9.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* lm77.c - Part of lm_sensors, Linux kernel modules for hardware |
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* monitoring |
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* |
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* Copyright (c) 2004 Andras BALI <[email protected]> |
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* |
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* Heavily based on lm75.c by Frodo Looijaard <[email protected]>. The LM77 |
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* is a temperature sensor and thermal window comparator with 0.5 deg |
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* resolution made by National Semiconductor. Complete datasheet can be |
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* obtained at their site: |
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* http://www.national.com/pf/LM/LM77.html |
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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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/* Addresses to scan */ |
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static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, |
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I2C_CLIENT_END }; |
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/* The LM77 registers */ |
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#define LM77_REG_TEMP 0x00 |
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#define LM77_REG_CONF 0x01 |
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#define LM77_REG_TEMP_HYST 0x02 |
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#define LM77_REG_TEMP_CRIT 0x03 |
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#define LM77_REG_TEMP_MIN 0x04 |
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#define LM77_REG_TEMP_MAX 0x05 |
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enum temp_index { |
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t_input = 0, |
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t_crit, |
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t_min, |
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t_max, |
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t_hyst, |
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t_num_temp |
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}; |
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static const u8 temp_regs[t_num_temp] = { |
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[t_input] = LM77_REG_TEMP, |
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[t_min] = LM77_REG_TEMP_MIN, |
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[t_max] = LM77_REG_TEMP_MAX, |
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[t_crit] = LM77_REG_TEMP_CRIT, |
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[t_hyst] = LM77_REG_TEMP_HYST, |
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}; |
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/* Each client has this additional data */ |
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struct lm77_data { |
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struct i2c_client *client; |
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struct mutex update_lock; |
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char valid; |
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unsigned long last_updated; /* In jiffies */ |
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int temp[t_num_temp]; /* index using temp_index */ |
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u8 alarms; |
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}; |
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/* straight from the datasheet */ |
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#define LM77_TEMP_MIN (-55000) |
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#define LM77_TEMP_MAX 125000 |
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/* |
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* In the temperature registers, the low 3 bits are not part of the |
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* temperature values; they are the status bits. |
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*/ |
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static inline s16 LM77_TEMP_TO_REG(int temp) |
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{ |
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return (temp / 500) * 8; |
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} |
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static inline int LM77_TEMP_FROM_REG(s16 reg) |
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{ |
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return (reg / 8) * 500; |
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} |
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/* |
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* All registers are word-sized, except for the configuration register. |
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* The LM77 uses the high-byte first convention. |
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*/ |
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static u16 lm77_read_value(struct i2c_client *client, u8 reg) |
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{ |
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if (reg == LM77_REG_CONF) |
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return i2c_smbus_read_byte_data(client, reg); |
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else |
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return i2c_smbus_read_word_swapped(client, reg); |
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} |
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static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) |
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{ |
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if (reg == LM77_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_swapped(client, reg, value); |
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} |
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static struct lm77_data *lm77_update_device(struct device *dev) |
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{ |
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struct lm77_data *data = dev_get_drvdata(dev); |
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struct i2c_client *client = data->client; |
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int i; |
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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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dev_dbg(&client->dev, "Starting lm77 update\n"); |
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for (i = 0; i < t_num_temp; i++) { |
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data->temp[i] = |
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LM77_TEMP_FROM_REG(lm77_read_value(client, |
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temp_regs[i])); |
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} |
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data->alarms = |
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lm77_read_value(client, LM77_REG_TEMP) & 0x0007; |
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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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/* sysfs stuff */ |
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static ssize_t temp_show(struct device *dev, struct device_attribute *devattr, |
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char *buf) |
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{ |
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struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); |
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struct lm77_data *data = lm77_update_device(dev); |
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return sprintf(buf, "%d\n", data->temp[attr->index]); |
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} |
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static ssize_t temp_hyst_show(struct device *dev, |
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struct device_attribute *devattr, char *buf) |
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{ |
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struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); |
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struct lm77_data *data = lm77_update_device(dev); |
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int nr = attr->index; |
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int temp; |
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temp = nr == t_min ? data->temp[nr] + data->temp[t_hyst] : |
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data->temp[nr] - data->temp[t_hyst]; |
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return sprintf(buf, "%d\n", temp); |
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} |
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static ssize_t temp_store(struct device *dev, |
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struct device_attribute *devattr, const char *buf, |
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size_t count) |
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{ |
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struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); |
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struct lm77_data *data = dev_get_drvdata(dev); |
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struct i2c_client *client = data->client; |
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int nr = attr->index; |
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long val; |
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int err; |
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err = kstrtol(buf, 10, &val); |
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if (err) |
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return err; |
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val = clamp_val(val, LM77_TEMP_MIN, LM77_TEMP_MAX); |
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mutex_lock(&data->update_lock); |
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data->temp[nr] = val; |
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lm77_write_value(client, temp_regs[nr], LM77_TEMP_TO_REG(val)); |
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mutex_unlock(&data->update_lock); |
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return count; |
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} |
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/* |
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* hysteresis is stored as a relative value on the chip, so it has to be |
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* converted first. |
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*/ |
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static ssize_t temp_hyst_store(struct device *dev, |
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struct device_attribute *devattr, |
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const char *buf, size_t count) |
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{ |
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struct lm77_data *data = dev_get_drvdata(dev); |
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struct i2c_client *client = data->client; |
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long val; |
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int err; |
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err = kstrtol(buf, 10, &val); |
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if (err) |
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return err; |
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mutex_lock(&data->update_lock); |
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val = clamp_val(data->temp[t_crit] - val, LM77_TEMP_MIN, LM77_TEMP_MAX); |
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data->temp[t_hyst] = val; |
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lm77_write_value(client, LM77_REG_TEMP_HYST, |
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LM77_TEMP_TO_REG(data->temp[t_hyst])); |
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mutex_unlock(&data->update_lock); |
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return count; |
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} |
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static ssize_t alarm_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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int bitnr = to_sensor_dev_attr(attr)->index; |
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struct lm77_data *data = lm77_update_device(dev); |
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return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1); |
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} |
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static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, t_input); |
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static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit); |
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static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min); |
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static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max); |
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static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit); |
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static SENSOR_DEVICE_ATTR_RO(temp1_min_hyst, temp_hyst, t_min); |
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static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max); |
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static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2); |
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static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0); |
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static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 1); |
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static struct attribute *lm77_attrs[] = { |
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&sensor_dev_attr_temp1_input.dev_attr.attr, |
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&sensor_dev_attr_temp1_crit.dev_attr.attr, |
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&sensor_dev_attr_temp1_min.dev_attr.attr, |
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&sensor_dev_attr_temp1_max.dev_attr.attr, |
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&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr, |
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&sensor_dev_attr_temp1_min_hyst.dev_attr.attr, |
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&sensor_dev_attr_temp1_max_hyst.dev_attr.attr, |
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&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, |
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&sensor_dev_attr_temp1_min_alarm.dev_attr.attr, |
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&sensor_dev_attr_temp1_max_alarm.dev_attr.attr, |
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NULL |
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}; |
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ATTRIBUTE_GROUPS(lm77); |
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/* Return 0 if detection is successful, -ENODEV otherwise */ |
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static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info) |
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{ |
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struct i2c_adapter *adapter = client->adapter; |
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int i, cur, conf, hyst, crit, min, max; |
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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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return -ENODEV; |
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/* |
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* Here comes the remaining detection. Since the LM77 has no |
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* register dedicated to identification, we have to rely on the |
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* following tricks: |
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* |
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* 1. the high 4 bits represent the sign and thus they should |
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* always be the same |
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* 2. the high 3 bits are unused in the configuration register |
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* 3. addresses 0x06 and 0x07 return the last read value |
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* 4. registers cycling over 8-address boundaries |
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* |
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* Word-sized registers are high-byte first. |
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*/ |
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/* addresses cycling */ |
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cur = i2c_smbus_read_word_data(client, 0); |
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conf = i2c_smbus_read_byte_data(client, 1); |
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hyst = i2c_smbus_read_word_data(client, 2); |
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crit = i2c_smbus_read_word_data(client, 3); |
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min = i2c_smbus_read_word_data(client, 4); |
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max = i2c_smbus_read_word_data(client, 5); |
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for (i = 8; i <= 0xff; i += 8) { |
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if (i2c_smbus_read_byte_data(client, i + 1) != conf |
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|| i2c_smbus_read_word_data(client, i + 2) != hyst |
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|| i2c_smbus_read_word_data(client, i + 3) != crit |
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|| i2c_smbus_read_word_data(client, i + 4) != min |
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|| i2c_smbus_read_word_data(client, i + 5) != max) |
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return -ENODEV; |
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} |
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/* sign bits */ |
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if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) |
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|| ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) |
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|| ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) |
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|| ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) |
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|| ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) |
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return -ENODEV; |
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/* unused bits */ |
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if (conf & 0xe0) |
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return -ENODEV; |
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/* 0x06 and 0x07 return the last read value */ |
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cur = i2c_smbus_read_word_data(client, 0); |
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if (i2c_smbus_read_word_data(client, 6) != cur |
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|| i2c_smbus_read_word_data(client, 7) != cur) |
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return -ENODEV; |
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hyst = i2c_smbus_read_word_data(client, 2); |
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if (i2c_smbus_read_word_data(client, 6) != hyst |
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|| i2c_smbus_read_word_data(client, 7) != hyst) |
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return -ENODEV; |
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min = i2c_smbus_read_word_data(client, 4); |
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if (i2c_smbus_read_word_data(client, 6) != min |
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|| i2c_smbus_read_word_data(client, 7) != min) |
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return -ENODEV; |
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strlcpy(info->type, "lm77", I2C_NAME_SIZE); |
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return 0; |
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} |
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static void lm77_init_client(struct i2c_client *client) |
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{ |
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/* Initialize the LM77 chip - turn off shutdown mode */ |
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int conf = lm77_read_value(client, LM77_REG_CONF); |
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if (conf & 1) |
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lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); |
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} |
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static int lm77_probe(struct i2c_client *client) |
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{ |
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struct device *dev = &client->dev; |
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struct device *hwmon_dev; |
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struct lm77_data *data; |
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data = devm_kzalloc(dev, sizeof(struct lm77_data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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data->client = client; |
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mutex_init(&data->update_lock); |
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/* Initialize the LM77 chip */ |
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lm77_init_client(client); |
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hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
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data, lm77_groups); |
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return PTR_ERR_OR_ZERO(hwmon_dev); |
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} |
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static const struct i2c_device_id lm77_id[] = { |
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{ "lm77", 0 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, lm77_id); |
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/* This is the driver that will be inserted */ |
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static struct i2c_driver lm77_driver = { |
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.class = I2C_CLASS_HWMON, |
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.driver = { |
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.name = "lm77", |
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}, |
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.probe_new = lm77_probe, |
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.id_table = lm77_id, |
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.detect = lm77_detect, |
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.address_list = normal_i2c, |
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}; |
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module_i2c_driver(lm77_driver); |
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MODULE_AUTHOR("Andras BALI <[email protected]>"); |
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MODULE_DESCRIPTION("LM77 driver"); |
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MODULE_LICENSE("GPL");
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