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172 lines
3.6 KiB
172 lines
3.6 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* An hwmon driver for the Microchip TC74 |
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* |
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* Copyright 2015 Maciej Szmigiero <[email protected]> |
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* |
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* Based on ad7414.c: |
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* Copyright 2006 Stefan Roese, DENX Software Engineering |
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* Copyright 2008 Sean MacLennan, PIKA Technologies |
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* Copyright 2008 Frank Edelhaeuser, Spansion Inc. |
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*/ |
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#include <linux/bitops.h> |
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#include <linux/err.h> |
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#include <linux/hwmon.h> |
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#include <linux/hwmon-sysfs.h> |
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#include <linux/i2c.h> |
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#include <linux/jiffies.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/slab.h> |
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#include <linux/sysfs.h> |
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/* TC74 registers */ |
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#define TC74_REG_TEMP 0x00 |
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#define TC74_REG_CONFIG 0x01 |
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struct tc74_data { |
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struct i2c_client *client; |
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struct mutex lock; /* atomic read data updates */ |
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bool valid; /* validity of fields below */ |
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unsigned long next_update; /* In jiffies */ |
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s8 temp_input; /* Temp value in dC */ |
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}; |
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static int tc74_update_device(struct device *dev) |
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{ |
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struct tc74_data *data = dev_get_drvdata(dev); |
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struct i2c_client *client = data->client; |
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int ret; |
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ret = mutex_lock_interruptible(&data->lock); |
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if (ret) |
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return ret; |
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if (time_after(jiffies, data->next_update) || !data->valid) { |
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s32 value; |
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value = i2c_smbus_read_byte_data(client, TC74_REG_CONFIG); |
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if (value < 0) { |
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dev_dbg(&client->dev, "TC74_REG_CONFIG read err %d\n", |
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(int)value); |
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ret = value; |
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goto ret_unlock; |
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} |
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if (!(value & BIT(6))) { |
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/* not ready yet */ |
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ret = -EAGAIN; |
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goto ret_unlock; |
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} |
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value = i2c_smbus_read_byte_data(client, TC74_REG_TEMP); |
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if (value < 0) { |
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dev_dbg(&client->dev, "TC74_REG_TEMP read err %d\n", |
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(int)value); |
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ret = value; |
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goto ret_unlock; |
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} |
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data->temp_input = value; |
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data->next_update = jiffies + HZ / 4; |
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data->valid = true; |
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} |
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ret_unlock: |
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mutex_unlock(&data->lock); |
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return ret; |
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} |
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static ssize_t temp_input_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct tc74_data *data = dev_get_drvdata(dev); |
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int ret; |
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ret = tc74_update_device(dev); |
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if (ret) |
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return ret; |
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return sprintf(buf, "%d\n", data->temp_input * 1000); |
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} |
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static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_input, 0); |
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static struct attribute *tc74_attrs[] = { |
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&sensor_dev_attr_temp1_input.dev_attr.attr, |
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NULL |
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}; |
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ATTRIBUTE_GROUPS(tc74); |
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static int tc74_probe(struct i2c_client *client) |
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{ |
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struct device *dev = &client->dev; |
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struct tc74_data *data; |
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struct device *hwmon_dev; |
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s32 conf; |
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) |
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return -EOPNOTSUPP; |
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data = devm_kzalloc(dev, sizeof(struct tc74_data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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data->client = client; |
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mutex_init(&data->lock); |
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/* Make sure the chip is powered up. */ |
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conf = i2c_smbus_read_byte_data(client, TC74_REG_CONFIG); |
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if (conf < 0) { |
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dev_err(dev, "unable to read config register\n"); |
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return conf; |
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} |
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if (conf & 0x3f) { |
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dev_err(dev, "invalid config register value\n"); |
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return -ENODEV; |
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} |
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if (conf & BIT(7)) { |
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s32 ret; |
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conf &= ~BIT(7); |
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ret = i2c_smbus_write_byte_data(client, TC74_REG_CONFIG, conf); |
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if (ret) |
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dev_warn(dev, "unable to disable STANDBY\n"); |
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} |
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hwmon_dev = devm_hwmon_device_register_with_groups(dev, |
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client->name, |
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data, tc74_groups); |
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return PTR_ERR_OR_ZERO(hwmon_dev); |
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} |
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static const struct i2c_device_id tc74_id[] = { |
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{ "tc74", 0 }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(i2c, tc74_id); |
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static struct i2c_driver tc74_driver = { |
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.driver = { |
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.name = "tc74", |
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}, |
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.probe_new = tc74_probe, |
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.id_table = tc74_id, |
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}; |
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module_i2c_driver(tc74_driver); |
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MODULE_AUTHOR("Maciej Szmigiero <[email protected]>"); |
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MODULE_DESCRIPTION("TC74 driver"); |
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MODULE_LICENSE("GPL");
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