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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. Avoid auto-conversion from long to int to fix the problem. The hysteresis temperature range depends on the value of data->temp[attr->index], since val is subtracted from it. Use a wider clamp, [-120000, 220000] should do to cover the possible range. Also add missing TEMP_TO_REG() on writes into cached hysteresis value. Also uses clamp_val to simplify the code a bit. Signed-off-by: Axel Lin <axel.lin@ingics.com> [Guenter Roeck: Fixed double TEMP_TO_REG on hysteresis updates] Cc: stable@vger.kernel.org Signed-off-by: Guenter Roeck <linux@roeck-us.net>
411 lines
12 KiB
C
411 lines
12 KiB
C
/*
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* lm92 - Hardware monitoring driver
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* Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>
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*
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* Based on the lm90 driver, with some ideas taken from the lm_sensors
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* lm92 driver as well.
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*
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* The LM92 is a sensor chip made by National Semiconductor. It reports
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* its own temperature with a 0.0625 deg resolution and a 0.33 deg
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* accuracy. Complete datasheet can be obtained from National's website
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* at:
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* http://www.national.com/pf/LM/LM92.html
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*
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* This driver also supports the MAX6635 sensor chip made by Maxim.
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* This chip is compatible with the LM92, but has a lesser accuracy
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* (1.0 deg). Complete datasheet can be obtained from Maxim's website
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* at:
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* http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
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*
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* Since the LM92 was the first chipset supported by this driver, most
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* comments will refer to this chipset, but are actually general and
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* concern all supported chipsets, unless mentioned otherwise.
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*
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* Support could easily be added for the National Semiconductor LM76
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* and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
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* with the LM92.
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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/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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#include <linux/jiffies.h>
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/*
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* The LM92 and MAX6635 have 2 two-state pins for address selection,
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* resulting in 4 possible addresses.
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*/
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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 LM92 registers */
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#define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
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#define LM92_REG_TEMP 0x00 /* 16-bit, RO */
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#define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
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#define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
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#define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
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#define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
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#define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
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/*
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* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
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* left-justified in 16-bit registers. No rounding is done, with such
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* a resolution it's just not worth it. Note that the MAX6635 doesn't
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* make use of the 4 lower bits for limits (i.e. effective resolution
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* for limits is 1 degree Celsius).
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*/
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static inline int TEMP_FROM_REG(s16 reg)
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{
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return reg / 8 * 625 / 10;
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}
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static inline s16 TEMP_TO_REG(long val)
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{
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val = clamp_val(val, -60000, 160000);
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return val * 10 / 625 * 8;
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}
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/* Alarm flags are stored in the 3 LSB of the temperature register */
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static inline u8 ALARMS_FROM_REG(s16 reg)
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{
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return reg & 0x0007;
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}
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enum temp_index {
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t_input,
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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_regs
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};
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static const u8 regs[t_num_regs] = {
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[t_input] = LM92_REG_TEMP,
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[t_crit] = LM92_REG_TEMP_CRIT,
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[t_min] = LM92_REG_TEMP_LOW,
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[t_max] = LM92_REG_TEMP_HIGH,
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[t_hyst] = LM92_REG_TEMP_HYST,
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};
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/* Client data (each client gets its own) */
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struct lm92_data {
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struct i2c_client *client;
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struct mutex update_lock;
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char valid; /* zero until following fields are valid */
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unsigned long last_updated; /* in jiffies */
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/* registers values */
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s16 temp[t_num_regs]; /* index with enum temp_index */
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};
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/*
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* Sysfs attributes and callback functions
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*/
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static struct lm92_data *lm92_update_device(struct device *dev)
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{
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struct lm92_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)
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|| !data->valid) {
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dev_dbg(&client->dev, "Updating lm92 data\n");
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for (i = 0; i < t_num_regs; i++) {
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data->temp[i] =
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i2c_smbus_read_word_swapped(client, regs[i]);
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}
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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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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 lm92_data *data = lm92_update_device(dev);
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return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
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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 lm92_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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mutex_lock(&data->update_lock);
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data->temp[nr] = TEMP_TO_REG(val);
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i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]);
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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_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 lm92_data *data = lm92_update_device(dev);
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return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])
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- TEMP_FROM_REG(data->temp[t_hyst]));
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}
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static ssize_t show_temp_min_hyst(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct lm92_data *data = lm92_update_device(dev);
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return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min])
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+ TEMP_FROM_REG(data->temp[t_hyst]));
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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 sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
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struct lm92_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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val = clamp_val(val, -120000, 220000);
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mutex_lock(&data->update_lock);
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data->temp[t_hyst] =
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TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val);
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i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
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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_alarms(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct lm92_data *data = lm92_update_device(dev);
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return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input]));
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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 lm92_data *data = lm92_update_device(dev);
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return sprintf(buf, "%d\n", (data->temp[t_input] >> 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_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, S_IWUSR | S_IRUGO, show_temp, set_temp,
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t_min);
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static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp_min_hyst, NULL);
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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_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max);
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static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
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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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/*
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* Detection and registration
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*/
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static void lm92_init_client(struct i2c_client *client)
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{
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u8 config;
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/* Start the conversions if needed */
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config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
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if (config & 0x01)
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i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
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config & 0xFE);
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}
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/*
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* The MAX6635 has no identification register, so we have to use tricks
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* to identify it reliably. This is somewhat slow.
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* Note that we do NOT rely on the 2 MSB of the configuration register
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* always reading 0, as suggested by the datasheet, because it was once
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* reported not to be true.
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*/
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static int max6635_check(struct i2c_client *client)
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{
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u16 temp_low, temp_high, temp_hyst, temp_crit;
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u8 conf;
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int i;
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/*
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* No manufacturer ID register, so a read from this address will
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* always return the last read value.
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*/
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temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
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if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
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return 0;
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temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
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if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
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return 0;
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/* Limits are stored as integer values (signed, 9-bit). */
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if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
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return 0;
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temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
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temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
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if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
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return 0;
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/*
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* Registers addresses were found to cycle over 16-byte boundaries.
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* We don't test all registers with all offsets so as to save some
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* reads and time, but this should still be sufficient to dismiss
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* non-MAX6635 chips.
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*/
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conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
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for (i = 16; i < 96; i *= 2) {
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if (temp_hyst != i2c_smbus_read_word_data(client,
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LM92_REG_TEMP_HYST + i - 16)
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|| temp_crit != i2c_smbus_read_word_data(client,
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LM92_REG_TEMP_CRIT + i)
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|| temp_low != i2c_smbus_read_word_data(client,
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LM92_REG_TEMP_LOW + i + 16)
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|| temp_high != i2c_smbus_read_word_data(client,
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LM92_REG_TEMP_HIGH + i + 32)
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|| conf != i2c_smbus_read_byte_data(client,
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LM92_REG_CONFIG + i))
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return 0;
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}
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return 1;
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}
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static struct attribute *lm92_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_crit_hyst.dev_attr.attr,
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&sensor_dev_attr_temp1_min.dev_attr.attr,
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&dev_attr_temp1_min_hyst.attr,
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&sensor_dev_attr_temp1_max.dev_attr.attr,
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&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
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&dev_attr_alarms.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(lm92);
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/* Return 0 if detection is successful, -ENODEV otherwise */
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static int lm92_detect(struct i2c_client *new_client,
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struct i2c_board_info *info)
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{
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struct i2c_adapter *adapter = new_client->adapter;
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u8 config;
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u16 man_id;
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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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config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
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man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
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if ((config & 0xe0) == 0x00 && man_id == 0x0180)
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pr_info("lm92: Found National Semiconductor LM92 chip\n");
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else if (max6635_check(new_client))
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pr_info("lm92: Found Maxim MAX6635 chip\n");
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else
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return -ENODEV;
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strlcpy(info->type, "lm92", I2C_NAME_SIZE);
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return 0;
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}
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static int lm92_probe(struct i2c_client *new_client,
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const struct i2c_device_id *id)
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{
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struct device *hwmon_dev;
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struct lm92_data *data;
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data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
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GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->client = new_client;
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mutex_init(&data->update_lock);
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/* Initialize the chipset */
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lm92_init_client(new_client);
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hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
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new_client->name,
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data, lm92_groups);
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return PTR_ERR_OR_ZERO(hwmon_dev);
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}
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/*
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* Module and driver stuff
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*/
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static const struct i2c_device_id lm92_id[] = {
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{ "lm92", 0 },
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/* max6635 could be added here */
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, lm92_id);
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static struct i2c_driver lm92_driver = {
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.class = I2C_CLASS_HWMON,
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.driver = {
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.name = "lm92",
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},
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.probe = lm92_probe,
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.id_table = lm92_id,
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.detect = lm92_detect,
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.address_list = normal_i2c,
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};
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module_i2c_driver(lm92_driver);
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MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
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MODULE_DESCRIPTION("LM92/MAX6635 driver");
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MODULE_LICENSE("GPL");
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