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![Axel Lin](/assets/img/avatar_default.png)
On platforms with sizeof(int) < sizeof(long), writing a temperature limit larger than MAXINT will result in unpredictable limit values written to the chip. Clamp the input values to the supported limits first to fix the problem. For set_temp_hyst: As Guenter pointed out that the temperature is read as unsigned and stored in an unsigned long. This is wrong; nothing in the datasheet suggests that the value (the absolute temperature) must be positive. So change it to signed. Signed-off-by: Axel Lin <axel.lin@ingics.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
373 lines
11 KiB
C
373 lines
11 KiB
C
/*
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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 <drewie@freemail.hu>
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*
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* Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. 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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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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 show_temp(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 show_temp_hyst(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 set_temp(struct device *dev, struct device_attribute *devattr,
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const char *buf, 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 set_temp_hyst(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 show_alarm(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(temp1_input, S_IRUGO, show_temp, NULL, t_input);
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static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp, set_temp,
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t_crit);
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static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp,
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t_min);
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static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp,
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t_max);
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static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp_hyst,
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set_temp_hyst, t_crit);
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static SENSOR_DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp_hyst, NULL, t_min);
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static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max);
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static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
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static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
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static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 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, const struct i2c_device_id *id)
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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 = 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 <drewie@freemail.hu>");
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MODULE_DESCRIPTION("LM77 driver");
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MODULE_LICENSE("GPL");
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