From 761c1770f2bf36a323ab97e2e1780db4f9b8a6fe Mon Sep 17 00:00:00 2001 From: "Maciej S. Szmigiero" Date: Sun, 21 Jun 2015 15:54:44 +0200 Subject: [PATCH] hwmon: add driver for Microchip TC74 Add hwmon driver for the Microchip TC74. The TC74 is a single-input 8-bit I2C temperature sensor, with +-2 degrees centigrade accuracy. Signed-off-by: Maciej Szmigiero Signed-off-by: Guenter Roeck --- Documentation/hwmon/tc74 | 20 +++++ drivers/hwmon/Kconfig | 10 +++ drivers/hwmon/Makefile | 1 + drivers/hwmon/tc74.c | 177 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 208 insertions(+) create mode 100644 Documentation/hwmon/tc74 create mode 100644 drivers/hwmon/tc74.c diff --git a/Documentation/hwmon/tc74 b/Documentation/hwmon/tc74 new file mode 100644 index 000000000000..43027aad5f8e --- /dev/null +++ b/Documentation/hwmon/tc74 @@ -0,0 +1,20 @@ +Kernel driver tc74 +==================== + +Supported chips: + * Microchip TC74 + Prefix: 'tc74' + Datasheet: Publicly available at Microchip website. + +Description +----------- + +Driver supports the above part. + +The tc74 has an 8-bit sensor, with 1 degree centigrade resolution +and +- 2 degrees centigrade accuracy. + +Notes +----- + +Currently entering low power standby mode is not supported. diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index 9c9d38b1e92e..54075a07d2a1 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -1452,6 +1452,16 @@ config SENSORS_INA2XX This driver can also be built as a module. If so, the module will be called ina2xx. +config SENSORS_TC74 + tristate "Microchip TC74" + depends on I2C + help + If you say yes here you get support for Microchip TC74 single + input temperature sensor chips. + + This driver can also be built as a module. If so, the module + will be called tc74. + config SENSORS_THMC50 tristate "Texas Instruments THMC50 / Analog Devices ADM1022" depends on I2C diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index b4a40f17e2aa..ab904027f074 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -140,6 +140,7 @@ obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o obj-$(CONFIG_SENSORS_AMC6821) += amc6821.o +obj-$(CONFIG_SENSORS_TC74) += tc74.o obj-$(CONFIG_SENSORS_THMC50) += thmc50.o obj-$(CONFIG_SENSORS_TMP102) += tmp102.o obj-$(CONFIG_SENSORS_TMP103) += tmp103.o diff --git a/drivers/hwmon/tc74.c b/drivers/hwmon/tc74.c new file mode 100644 index 000000000000..d95165158800 --- /dev/null +++ b/drivers/hwmon/tc74.c @@ -0,0 +1,177 @@ +/* + * An hwmon driver for the Microchip TC74 + * + * Copyright 2015 Maciej Szmigiero + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* 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 "); + +MODULE_DESCRIPTION("TC74 driver"); +MODULE_LICENSE("GPL"); -- GitLab