diff options
Diffstat (limited to 'drivers/hwmon/tc74.c')
| -rw-r--r-- | drivers/hwmon/tc74.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/drivers/hwmon/tc74.c b/drivers/hwmon/tc74.c new file mode 100644 index 000000000..d95165158 --- /dev/null +++ b/drivers/hwmon/tc74.c @@ -0,0 +1,177 @@ +/* + * An hwmon driver for the Microchip TC74 + * + * Copyright 2015 Maciej Szmigiero <mail@maciej.szmigiero.name> + * + * Based on ad7414.c: + * Copyright 2006 Stefan Roese, DENX Software Engineering + * Copyright 2008 Sean MacLennan, PIKA Technologies + * Copyright 2008 Frank Edelhaeuser, Spansion Inc. + * + * 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. + */ + +#include <linux/bitops.h> +#include <linux/err.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> +#include <linux/i2c.h> +#include <linux/jiffies.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/sysfs.h> + +/* TC74 registers */ +#define TC74_REG_TEMP 0x00 +#define TC74_REG_CONFIG 0x01 + +struct tc74_data { + struct i2c_client *client; + struct mutex lock; /* atomic read data updates */ + bool valid; /* validity of fields below */ + unsigned long next_update; /* In jiffies */ + s8 temp_input; /* Temp value in dC */ +}; + +static int tc74_update_device(struct device *dev) +{ + struct tc74_data *data = dev_get_drvdata(dev); + struct i2c_client *client = data->client; + int ret; + + ret = mutex_lock_interruptible(&data->lock); + if (ret) + return ret; + + if (time_after(jiffies, data->next_update) || !data->valid) { + s32 value; + + value = i2c_smbus_read_byte_data(client, TC74_REG_CONFIG); + if (value < 0) { + dev_dbg(&client->dev, "TC74_REG_CONFIG read err %d\n", + (int)value); + + ret = value; + goto ret_unlock; + } + + if (!(value & BIT(6))) { + /* not ready yet */ + + ret = -EAGAIN; + goto ret_unlock; + } + + value = i2c_smbus_read_byte_data(client, TC74_REG_TEMP); + if (value < 0) { + dev_dbg(&client->dev, "TC74_REG_TEMP read err %d\n", + (int)value); + + ret = value; + goto ret_unlock; + } + + data->temp_input = value; + data->next_update = jiffies + HZ / 4; + data->valid = true; + } + +ret_unlock: + mutex_unlock(&data->lock); + + return ret; +} + +static ssize_t show_temp_input(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct tc74_data *data = dev_get_drvdata(dev); + int ret; + + ret = tc74_update_device(dev); + if (ret) + return ret; + + return sprintf(buf, "%d\n", data->temp_input * 1000); +} +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0); + +static struct attribute *tc74_attrs[] = { + &sensor_dev_attr_temp1_input.dev_attr.attr, + NULL +}; + +ATTRIBUTE_GROUPS(tc74); + +static int tc74_probe(struct i2c_client *client, + const struct i2c_device_id *dev_id) +{ + struct device *dev = &client->dev; + struct tc74_data *data; + struct device *hwmon_dev; + s32 conf; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) + return -EOPNOTSUPP; + + data = devm_kzalloc(dev, sizeof(struct tc74_data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->client = client; + mutex_init(&data->lock); + + /* Make sure the chip is powered up. */ + conf = i2c_smbus_read_byte_data(client, TC74_REG_CONFIG); + if (conf < 0) { + dev_err(dev, "unable to read config register\n"); + + return conf; + } + + if (conf & 0x3f) { + dev_err(dev, "invalid config register value\n"); + + return -ENODEV; + } + + if (conf & BIT(7)) { + s32 ret; + + conf &= ~BIT(7); + + ret = i2c_smbus_write_byte_data(client, TC74_REG_CONFIG, conf); + if (ret) + dev_warn(dev, "unable to disable STANDBY\n"); + } + + hwmon_dev = devm_hwmon_device_register_with_groups(dev, + client->name, + data, tc74_groups); + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +static const struct i2c_device_id tc74_id[] = { + { "tc74", 0 }, + {} +}; +MODULE_DEVICE_TABLE(i2c, tc74_id); + +static struct i2c_driver tc74_driver = { + .driver = { + .name = "tc74", + }, + .probe = tc74_probe, + .id_table = tc74_id, +}; + +module_i2c_driver(tc74_driver); + +MODULE_AUTHOR("Maciej Szmigiero <mail@maciej.szmigiero.name>"); + +MODULE_DESCRIPTION("TC74 driver"); +MODULE_LICENSE("GPL"); |