On Thu, 2011-03-31 at 14:34 -0400, Per DalÃn wrote: > MAX6642 is a SMBus-Compatible Remote/Local Temperature Sensor with > Overtemperature Alarm from Maxim. > > Signed-off-by: Per Dalen <per.dalen@xxxxxxxxxxxx> > > --- > diff --git a/Documentation/hwmon/max6642 b/Documentation/hwmon/max6642 > new file mode 100644 > index 0000000..fb8d40b > --- /dev/null > +++ b/Documentation/hwmon/max6642 > @@ -0,0 +1,21 @@ > +Kernel driver max6642 > +===================== > + > +Supported chips: > + * Maxim MAX6642 > + Prefix: 'max6642' > + Addresses scanned: I2C 0x48-0x4f > + Datasheet: Publicly available at the Maxim website > + http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf > + > +Authors: > + Per Dalen <per.dalen@xxxxxxxxxxxx> > + > +Description > +----------- > + > +The MAX6642 is a digital temperature sensor. It senses its own > temperature as > +well as the temperature of up to one external diode. > + Not really "up to one", but exactly one. The internal sensor can be disabled, but not the external sensor. > +All temperature values are given in degrees Celsius. Resolution > +is 0.25 degree for the local temperature and for the remote temperature. > diff --git a/drivers/hwmon/max6642.c b/drivers/hwmon/max6642.c > new file mode 100644 > index 0000000..3009fb7 > --- /dev/null > +++ b/drivers/hwmon/max6642.c > @@ -0,0 +1,380 @@ > +/* > + * Driver for +/-1 degree C, SMBus-Compatible Remote/Local Temperature > Sensor > + * with Overtemperature Alarm > + * > + * Copyright (C) 2011 AppearTV AS > + * > + * Derived from: > + * > + * Based on the max1619 driver. > + * Copyright (C) 2003-2004 Alexey Fisher <fishor@xxxxxxx> > + * Jean Delvare <khali@xxxxxxxxxxxx> > + * > + * The MAX6642 is a sensor chip made by Maxim. > + * It reports up to two temperatures (its own plus up to > + * one external one). Complete datasheet can be > + * obtained from Maxim's website at: > + * http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, write to the Free Software > + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. > + */ > + > + > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/slab.h> > +#include <linux/jiffies.h> > +#include <linux/i2c.h> > +#include <linux/hwmon.h> > +#include <linux/hwmon-sysfs.h> > +#include <linux/err.h> > +#include <linux/mutex.h> > +#include <linux/sysfs.h> > + > +static const unsigned short normal_i2c[] = { > + 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; > + > +/* > + * The MAX6642 registers > + */ > + > +#define MAX6642_REG_R_MAN_ID 0xFE > +#define MAX6642_REG_R_CONFIG 0x03 > +#define MAX6642_REG_W_CONFIG 0x09 > +#define MAX6642_REG_R_STATUS 0x02 > +#define MAX6642_REG_R_LOCAL_TEMP 0x00 > +#define MAX6642_REG_R_LOCAL_TEMPL 0x11 > +#define MAX6642_REG_R_LOCAL_HIGH 0x05 > +#define MAX6642_REG_W_LOCAL_HIGH 0x0B > +#define MAX6642_REG_R_REMOTE_TEMP 0x01 > +#define MAX6642_REG_R_REMOTE_TEMPL 0x10 > +#define MAX6642_REG_R_REMOTE_HIGH 0x07 > +#define MAX6642_REG_W_REMOTE_HIGH 0x0D > + > +/* > + * Conversions > + */ > + > +static int temp_from_reg10(int val) > +{ > + return val * 250; > +} > + > +static int temp_from_reg(int val) > +{ > + return val * 1000; > +} > + > +static int temp_to_reg(int val) > +{ > + return val / 1000; > +} > + > +/* > + * Functions declaration > + */ > + > +static int max6642_probe(struct i2c_client *client, > + const struct i2c_device_id *id); > +static int max6642_detect(struct i2c_client *client, > + struct i2c_board_info *info); > +static void max6642_init_client(struct i2c_client *client); > +static int max6642_remove(struct i2c_client *client); > +static struct max6642_data *max6642_update_device(struct device *dev); > + If you rearrange the code a bit you can get rid of those forward declarations. > +/* > + * Driver data (common to all clients) > + */ > + > +static const struct i2c_device_id max6642_id[] = { > + { "max6642", 0 }, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, max6642_id); > + > +static struct i2c_driver max6642_driver = { > + .class = I2C_CLASS_HWMON, > + .driver = { > + .name = "max6642", > + }, > + .probe = max6642_probe, > + .remove = max6642_remove, > + .id_table = max6642_id, > + .detect = max6642_detect, > + .address_list = normal_i2c, > +}; > + > +/* > + * Client data (each client gets its own) > + */ > + > +struct max6642_data { > + struct device *hwmon_dev; > + struct mutex update_lock; > + char valid; /* zero until following fields are valid */ > + unsigned long last_updated; /* in jiffies */ > + > + /* registers values */ > + u16 temp_input1, temp_high1; /* local */ > + u16 temp_input2, temp_high2; /* remote */ > + u8 alarms; > +}; > + > +/* > + * Sysfs stuff > + */ > + > +#define show_temp10(value) \ > +static ssize_t show10_##value(struct device *dev, \ > + struct device_attribute *attr, char *buf) \ > +{ \ > + struct max6642_data *data = max6642_update_device(dev); \ > + return sprintf(buf, "%d\n", temp_from_reg10(data->value)); \ > +} > + > +show_temp10(temp_input1); > +show_temp10(temp_input2); > + > +#define show_temp(value) \ > +static ssize_t show_##value(struct device *dev, struct device_attribute > *attr, \ > + char *buf) \ > +{ \ > + struct max6642_data *data = max6642_update_device(dev); \ > + return sprintf(buf, "%d\n", temp_from_reg(data->value)); \ > +} > + > +show_temp(temp_high1); > +show_temp(temp_high2); > + > +#define set_temp(value, reg) \ > +static ssize_t set_##value(struct device *dev, struct device_attribute > *attr, \ > + const char *buf, size_t count) \ > +{ \ > + long val, err; \ > + struct i2c_client *client = to_i2c_client(dev); \ > + struct max6642_data *data = i2c_get_clientdata(client); \ > + err = kstrtol(buf, 10, &val); \ > + if (err < 0) \ > + return err; \ > +\ > + mutex_lock(&data->update_lock); \ > + data->value = temp_to_reg(val); \ > + i2c_smbus_write_byte_data(client, reg, data->value); \ > + mutex_unlock(&data->update_lock); \ > + return count; \ > +} > + > +set_temp(temp_high1, MAX6642_REG_W_LOCAL_HIGH); > +set_temp(temp_high2, MAX6642_REG_W_REMOTE_HIGH); > + > +static ssize_t show_alarms(struct device *dev, struct device_attribute > *attr, > + char *buf) > +{ > + struct max6642_data *data = max6642_update_device(dev); > + return sprintf(buf, "%d\n", data->alarms); > +} > + > +static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + int bitnr = to_sensor_dev_attr(attr)->index; > + struct max6642_data *data = max6642_update_device(dev); > + return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1); > +} > + > +static DEVICE_ATTR(temp1_input, S_IRUGO, show10_temp_input1, NULL); > +static DEVICE_ATTR(temp2_input, S_IRUGO, show10_temp_input2, NULL); > +static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_high1, > + set_temp_high1); > +static DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp_high2, > + set_temp_high2); > +static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); > +static SENSOR_DEVICE_ATTR(temp_fault, S_IRUGO, show_alarm, NULL, 2); > +static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6); > +static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 4); > + > +static struct attribute *max6642_attributes[] = { > + &dev_attr_temp1_input.attr, > + &dev_attr_temp2_input.attr, > + &dev_attr_temp1_max.attr, > + &dev_attr_temp2_max.attr, > + > + &dev_attr_alarms.attr, > + &sensor_dev_attr_temp_fault.dev_attr.attr, > + &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, > + &sensor_dev_attr_temp2_max_alarm.dev_attr.attr, > + NULL > +}; > + > +static const struct attribute_group max6642_group = { > + .attrs = max6642_attributes, > +}; > + > +/* > + * Real code > + */ > + > +/* Return 0 if detection is successful, -ENODEV otherwise */ > +static int max6642_detect(struct i2c_client *client, > + struct i2c_board_info *info) > +{ > + struct i2c_adapter *adapter = client->adapter; > + u8 reg_config, man_id; > + > + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) > + return -ENODEV; > + > + /* detection */ > + reg_config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG); > + if ((reg_config & 0x10) != 0x00) { > + dev_dbg(&adapter->dev, "MAX6642 detection failed at 0x%02x\n", > + client->addr); > + return -ENODEV; > + } Does this really work ? Datasheet says that POR config register state is 0x10, and it is a changeable bit, so this detection would really not work well. Also, config registers 3..0 are reserved, meaning it should be possible to use those for improved detection. The same applies to status bits 0, 1, 3, and 5. It would also make more sense to check the mfg ID first. > + > + /* identification */ > + man_id = i2c_smbus_read_byte_data(client, MAX6642_REG_R_MAN_ID); > + if (man_id != 0x4D) { > + dev_info(&adapter->dev, > + "Unsupported chip (man_id=0x%02X).\n", > + man_id); That means you'll get that message for all I2C chips in the 0x48..0x4f range (as long as the 1st check passes). Not really a good idea. > + return -ENODEV; > + } > + > + strlcpy(info->type, "max6642", I2C_NAME_SIZE); > + > + return 0; > +} > + > +static int max6642_probe(struct i2c_client *new_client, > + const struct i2c_device_id *id) > +{ > + struct max6642_data *data; > + int err; > + > + data = kzalloc(sizeof(struct max6642_data), GFP_KERNEL); > + if (!data) { > + err = -ENOMEM; > + goto exit; > + } > + > + i2c_set_clientdata(new_client, data); > + data->valid = 0; valid is really 0 by default and does not need to be set. > + mutex_init(&data->update_lock); > + > + /* Initialize the MAX6642 chip */ > + max6642_init_client(new_client); > + > + /* Register sysfs hooks */ > + err = sysfs_create_group(&new_client->dev.kobj, &max6642_group); > + if (err) > + goto exit_free; > + The internal sensor can be disabled. It might make sense to only report internal temperatures if it is enabled. > + data->hwmon_dev = hwmon_device_register(&new_client->dev); > + if (IS_ERR(data->hwmon_dev)) { > + err = PTR_ERR(data->hwmon_dev); > + goto exit_remove_files; > + } > + > + return 0; > + > +exit_remove_files: > + sysfs_remove_group(&new_client->dev.kobj, &max6642_group); > +exit_free: > + kfree(data); > +exit: > + return err; > +} > + > +static void max6642_init_client(struct i2c_client *client) > +{ > + u8 config; > + > + /* > + * Start the conversions. > + */ > + config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG); > + if (config & 0x40) > + i2c_smbus_write_byte_data(client, MAX6642_REG_W_CONFIG, > + config & 0xBF); /* run */ > +} > + > +static int max6642_remove(struct i2c_client *client) > +{ > + struct max6642_data *data = i2c_get_clientdata(client); > + > + hwmon_device_unregister(data->hwmon_dev); > + sysfs_remove_group(&client->dev.kobj, &max6642_group); > + > + kfree(data); > + return 0; > +} > + > +static struct max6642_data *max6642_update_device(struct device *dev) > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct max6642_data *data = i2c_get_clientdata(client); > + u16 val, tmp; > + > + mutex_lock(&data->update_lock); > + > + if (time_after(jiffies, data->last_updated + HZ * 8) || !data->valid) { > + dev_dbg(&client->dev, "Updating max6642 data.\n"); > + val = i2c_smbus_read_byte_data(client, > + MAX6642_REG_R_LOCAL_TEMPL); > + tmp = (val >> 6) & 3; > + val = i2c_smbus_read_byte_data(client, > + MAX6642_REG_R_LOCAL_TEMP); > + val = (val << 2) | tmp; > + data->temp_input1 = val; > + val = i2c_smbus_read_byte_data(client, > + MAX6642_REG_R_REMOTE_TEMPL); > + tmp = (val >> 6) & 3; > + val = i2c_smbus_read_byte_data(client, > + MAX6642_REG_R_REMOTE_TEMP); > + val = (val << 2) | tmp; > + data->temp_input2 = val; > + data->temp_high1 = i2c_smbus_read_byte_data(client, > + MAX6642_REG_R_LOCAL_HIGH); > + data->temp_high2 = i2c_smbus_read_byte_data(client, > + MAX6642_REG_R_REMOTE_HIGH); > + data->alarms = i2c_smbus_read_byte_data(client, > + MAX6642_REG_R_STATUS); > + > + data->last_updated = jiffies; > + data->valid = 1; > + } > + > + mutex_unlock(&data->update_lock); > + > + return data; > +} > + > +static int __init sensors_max6642_init(void) > +{ > + return i2c_add_driver(&max6642_driver); > +} > + > +static void __exit sensors_max6642_exit(void) > +{ > + i2c_del_driver(&max6642_driver); > +} > + > +MODULE_AUTHOR("Per Dalen <per.dalen@xxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("MAX6642 sensor driver"); > +MODULE_LICENSE("GPL"); > + > +module_init(sensors_max6642_init); > +module_exit(sensors_max6642_exit); > > > > _______________________________________________ > lm-sensors mailing list > lm-sensors@xxxxxxxxxxxxxx > http://lists.lm-sensors.org/mailman/listinfo/lm-sensors _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
