// 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; strlcpy(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 = 1; } 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, const struct i2c_device_id *id) { 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 = 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");