![Jean Delvare](/assets/img/avatar_default.png)
Just about every i2c chip driver sets the I2C_DF_NOTIFY flag, so we can simply make it the default and drop the flag. If any driver really doesn't want to be notified when i2c adapters are added, that driver can simply omit to set .attach_adapter. This approach is also more robust as it prevents accidental NULL pointer dereferences. Signed-off-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
436 lines
13 KiB
C
436 lines
13 KiB
C
/*
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* lm92 - Hardware monitoring driver
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* Copyright (C) 2005 Jean Delvare <khali@linux-fr.org>
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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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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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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/err.h>
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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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static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
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I2C_CLIENT_END };
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/* Insmod parameters */
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I2C_CLIENT_INSMOD_1(lm92);
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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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/* 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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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(int val)
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{
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if (val <= -60000)
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return -60000 * 10 / 625 * 8;
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if (val >= 160000)
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return 160000 * 10 / 625 * 8;
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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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/* Driver data (common to all clients) */
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static struct i2c_driver lm92_driver;
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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 class_device *class_dev;
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struct semaphore 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 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
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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 i2c_client *client = to_i2c_client(dev);
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struct lm92_data *data = i2c_get_clientdata(client);
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down(&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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data->temp1_input = swab16(i2c_smbus_read_word_data(client,
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LM92_REG_TEMP));
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data->temp1_hyst = swab16(i2c_smbus_read_word_data(client,
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LM92_REG_TEMP_HYST));
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data->temp1_crit = swab16(i2c_smbus_read_word_data(client,
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LM92_REG_TEMP_CRIT));
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data->temp1_min = swab16(i2c_smbus_read_word_data(client,
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LM92_REG_TEMP_LOW));
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data->temp1_max = swab16(i2c_smbus_read_word_data(client,
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LM92_REG_TEMP_HIGH));
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data->last_updated = jiffies;
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data->valid = 1;
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}
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up(&data->update_lock);
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return data;
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}
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#define show_temp(value) \
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static ssize_t show_##value(struct device *dev, 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->value)); \
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}
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show_temp(temp1_input);
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show_temp(temp1_crit);
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show_temp(temp1_min);
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show_temp(temp1_max);
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#define set_temp(value, reg) \
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static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \
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size_t count) \
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{ \
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struct i2c_client *client = to_i2c_client(dev); \
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struct lm92_data *data = i2c_get_clientdata(client); \
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long val = simple_strtol(buf, NULL, 10); \
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\
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down(&data->update_lock); \
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data->value = TEMP_TO_REG(val); \
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i2c_smbus_write_word_data(client, reg, swab16(data->value)); \
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up(&data->update_lock); \
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return count; \
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}
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set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
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set_temp(temp1_min, LM92_REG_TEMP_LOW);
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set_temp(temp1_max, LM92_REG_TEMP_HIGH);
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static ssize_t show_temp1_crit_hyst(struct device *dev, 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->temp1_crit)
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- TEMP_FROM_REG(data->temp1_hyst));
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}
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static ssize_t show_temp1_max_hyst(struct device *dev, 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->temp1_max)
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- TEMP_FROM_REG(data->temp1_hyst));
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}
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static ssize_t show_temp1_min_hyst(struct device *dev, 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->temp1_min)
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+ TEMP_FROM_REG(data->temp1_hyst));
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}
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static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf,
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size_t count)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct lm92_data *data = i2c_get_clientdata(client);
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long val = simple_strtol(buf, NULL, 10);
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down(&data->update_lock);
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data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val;
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i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST,
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swab16(TEMP_TO_REG(data->temp1_hyst)));
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up(&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, 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->temp1_input));
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}
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static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
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static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
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set_temp1_crit);
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static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
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set_temp1_crit_hyst);
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static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
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set_temp1_min);
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static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
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static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
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set_temp1_max);
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static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
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static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
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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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/* 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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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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/* 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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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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/* 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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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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/* The following function does more than just detection. If detection
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succeeds, it also registers the new chip. */
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static int lm92_detect(struct i2c_adapter *adapter, int address, int kind)
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{
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struct i2c_client *new_client;
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struct lm92_data *data;
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int err = 0;
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char *name;
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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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goto exit;
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if (!(data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL))) {
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err = -ENOMEM;
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goto exit;
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}
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/* Fill in enough client fields so that we can read from the chip,
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which is required for identication */
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new_client = &data->client;
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i2c_set_clientdata(new_client, data);
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new_client->addr = address;
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new_client->adapter = adapter;
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new_client->driver = &lm92_driver;
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new_client->flags = 0;
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/* A negative kind means that the driver was loaded with no force
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parameter (default), so we must identify the chip. */
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if (kind < 0) {
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u8 config = i2c_smbus_read_byte_data(new_client,
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LM92_REG_CONFIG);
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u16 man_id = i2c_smbus_read_word_data(new_client,
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LM92_REG_MAN_ID);
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if ((config & 0xe0) == 0x00
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&& man_id == 0x0180) {
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pr_info("lm92: Found National Semiconductor LM92 chip\n");
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kind = lm92;
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} else
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if (max6635_check(new_client)) {
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pr_info("lm92: Found Maxim MAX6635 chip\n");
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kind = lm92; /* No separate prefix */
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}
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else
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goto exit_free;
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} else
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if (kind == 0) /* Default to an LM92 if forced */
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kind = lm92;
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/* Give it the proper name */
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if (kind == lm92) {
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name = "lm92";
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} else { /* Supposedly cannot happen */
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dev_dbg(&new_client->dev, "Kind out of range?\n");
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goto exit_free;
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}
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/* Fill in the remaining client fields */
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strlcpy(new_client->name, name, I2C_NAME_SIZE);
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data->valid = 0;
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init_MUTEX(&data->update_lock);
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/* Tell the i2c subsystem a new client has arrived */
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if ((err = i2c_attach_client(new_client)))
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goto exit_free;
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/* Initialize the chipset */
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lm92_init_client(new_client);
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/* Register sysfs hooks */
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data->class_dev = hwmon_device_register(&new_client->dev);
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if (IS_ERR(data->class_dev)) {
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err = PTR_ERR(data->class_dev);
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goto exit_detach;
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}
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device_create_file(&new_client->dev, &dev_attr_temp1_input);
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device_create_file(&new_client->dev, &dev_attr_temp1_crit);
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device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst);
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device_create_file(&new_client->dev, &dev_attr_temp1_min);
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device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst);
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device_create_file(&new_client->dev, &dev_attr_temp1_max);
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device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst);
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device_create_file(&new_client->dev, &dev_attr_alarms);
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return 0;
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exit_detach:
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i2c_detach_client(new_client);
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exit_free:
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kfree(data);
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exit:
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return err;
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}
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static int lm92_attach_adapter(struct i2c_adapter *adapter)
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{
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if (!(adapter->class & I2C_CLASS_HWMON))
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return 0;
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return i2c_probe(adapter, &addr_data, lm92_detect);
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}
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static int lm92_detach_client(struct i2c_client *client)
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{
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struct lm92_data *data = i2c_get_clientdata(client);
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int err;
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hwmon_device_unregister(data->class_dev);
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if ((err = i2c_detach_client(client)))
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return err;
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kfree(data);
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return 0;
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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 struct i2c_driver lm92_driver = {
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.owner = THIS_MODULE,
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.name = "lm92",
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.id = I2C_DRIVERID_LM92,
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.attach_adapter = lm92_attach_adapter,
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.detach_client = lm92_detach_client,
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};
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static int __init sensors_lm92_init(void)
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{
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return i2c_add_driver(&lm92_driver);
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}
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static void __exit sensors_lm92_exit(void)
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{
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i2c_del_driver(&lm92_driver);
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}
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MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
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MODULE_DESCRIPTION("LM92/MAX6635 driver");
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MODULE_LICENSE("GPL");
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module_init(sensors_lm92_init);
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module_exit(sensors_lm92_exit);
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