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Diffstat (limited to '')
| -rw-r--r-- | drivers/hwmon/max6642.c | 314 |
1 files changed, 314 insertions, 0 deletions
diff --git a/drivers/hwmon/max6642.c b/drivers/hwmon/max6642.c new file mode 100644 index 000000000..47ea34ff7 --- /dev/null +++ b/drivers/hwmon/max6642.c @@ -0,0 +1,314 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * 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 Oleksij Rempel <bug-track@fisher-privat.net> + * Jean Delvare <jdelvare@suse.de> + * + * 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 + */ + + +#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; +} + +/* + * Client data (each client gets its own) + */ + +struct max6642_data { + struct i2c_client *client; + struct mutex update_lock; + bool valid; /* zero until following fields are valid */ + unsigned long last_updated; /* in jiffies */ + + /* registers values */ + u16 temp_input[2]; /* local/remote */ + u16 temp_high[2]; /* local/remote */ + u8 alarms; +}; + +/* + * Real code + */ + +static void max6642_init_client(struct max6642_data *data, + 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 */ + + data->temp_high[0] = i2c_smbus_read_byte_data(client, + MAX6642_REG_R_LOCAL_HIGH); + data->temp_high[1] = i2c_smbus_read_byte_data(client, + MAX6642_REG_R_REMOTE_HIGH); +} + +/* 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, reg_status, man_id; + + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) + return -ENODEV; + + /* identification */ + man_id = i2c_smbus_read_byte_data(client, MAX6642_REG_R_MAN_ID); + if (man_id != 0x4D) + return -ENODEV; + + /* sanity check */ + if (i2c_smbus_read_byte_data(client, 0x04) != 0x4D + || i2c_smbus_read_byte_data(client, 0x06) != 0x4D + || i2c_smbus_read_byte_data(client, 0xff) != 0x4D) + return -ENODEV; + + /* + * We read the config and status register, the 4 lower bits in the + * config register should be zero and bit 5, 3, 1 and 0 should be + * zero in the status register. + */ + reg_config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG); + if ((reg_config & 0x0f) != 0x00) + return -ENODEV; + + /* in between, another round of sanity checks */ + if (i2c_smbus_read_byte_data(client, 0x04) != reg_config + || i2c_smbus_read_byte_data(client, 0x06) != reg_config + || i2c_smbus_read_byte_data(client, 0xff) != reg_config) + return -ENODEV; + + reg_status = i2c_smbus_read_byte_data(client, MAX6642_REG_R_STATUS); + if ((reg_status & 0x2b) != 0x00) + return -ENODEV; + + strscpy(info->type, "max6642", I2C_NAME_SIZE); + + return 0; +} + +static struct max6642_data *max6642_update_device(struct device *dev) +{ + struct max6642_data *data = dev_get_drvdata(dev); + struct i2c_client *client = data->client; + u16 val, tmp; + + mutex_lock(&data->update_lock); + + if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { + dev_dbg(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_input[0] = 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_input[1] = val; + data->alarms = i2c_smbus_read_byte_data(client, + MAX6642_REG_R_STATUS); + + data->last_updated = jiffies; + data->valid = true; + } + + mutex_unlock(&data->update_lock); + + return data; +} + +/* + * Sysfs stuff + */ + +static ssize_t temp_max10_show(struct device *dev, + struct device_attribute *dev_attr, char *buf) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr); + struct max6642_data *data = max6642_update_device(dev); + + return sprintf(buf, "%d\n", + temp_from_reg10(data->temp_input[attr->index])); +} + +static ssize_t temp_max_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr); + struct max6642_data *data = max6642_update_device(dev); + + return sprintf(buf, "%d\n", temp_from_reg(data->temp_high[attr2->nr])); +} + +static ssize_t temp_max_store(struct device *dev, + struct device_attribute *attr, const char *buf, + size_t count) +{ + struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr); + struct max6642_data *data = dev_get_drvdata(dev); + unsigned long val; + int err; + + err = kstrtoul(buf, 10, &val); + if (err < 0) + return err; + + mutex_lock(&data->update_lock); + data->temp_high[attr2->nr] = clamp_val(temp_to_reg(val), 0, 255); + i2c_smbus_write_byte_data(data->client, attr2->index, + data->temp_high[attr2->nr]); + mutex_unlock(&data->update_lock); + return count; +} + +static ssize_t alarm_show(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 SENSOR_DEVICE_ATTR_RO(temp1_input, temp_max10, 0); +static SENSOR_DEVICE_ATTR_RO(temp2_input, temp_max10, 1); +static SENSOR_DEVICE_ATTR_2_RW(temp1_max, temp_max, 0, + MAX6642_REG_W_LOCAL_HIGH); +static SENSOR_DEVICE_ATTR_2_RW(temp2_max, temp_max, 1, + MAX6642_REG_W_REMOTE_HIGH); +static SENSOR_DEVICE_ATTR_RO(temp2_fault, alarm, 2); +static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 6); +static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, alarm, 4); + +static struct attribute *max6642_attrs[] = { + &sensor_dev_attr_temp1_input.dev_attr.attr, + &sensor_dev_attr_temp2_input.dev_attr.attr, + &sensor_dev_attr_temp1_max.dev_attr.attr, + &sensor_dev_attr_temp2_max.dev_attr.attr, + + &sensor_dev_attr_temp2_fault.dev_attr.attr, + &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, + &sensor_dev_attr_temp2_max_alarm.dev_attr.attr, + NULL +}; +ATTRIBUTE_GROUPS(max6642); + +static int max6642_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct max6642_data *data; + struct device *hwmon_dev; + + data = devm_kzalloc(dev, sizeof(struct max6642_data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->client = client; + mutex_init(&data->update_lock); + + /* Initialize the MAX6642 chip */ + max6642_init_client(data, client); + + hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev, + client->name, data, + max6642_groups); + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +/* + * 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_new = max6642_probe, + .id_table = max6642_id, + .detect = max6642_detect, + .address_list = normal_i2c, +}; + +module_i2c_driver(max6642_driver); + +MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>"); +MODULE_DESCRIPTION("MAX6642 sensor driver"); +MODULE_LICENSE("GPL"); |