hwmon: Driver for ADT7410

This patch brings basic support for the Analog Devices ADT7410 temperature
sensor. The following functionality has been implemented:

  * get current temperature
  * get/set minimum, maximum and critical temperature
  * get/set hysteresis
  * get alarm events for minimum, maximum and critical temperature

All implemented sysfs attributes have been sucessfully tested at temperatures
of 15°C to 40°C.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

4 files changed, 521 insertions, 0 deletions

diff --git a/Documentation/hwmon/adt7410 b/Documentation/hwmon/adt7410
new file mode 100644
index 000000000000..96004000dc2a
--- /dev/null
+++ b/Documentation/hwmon/adt7410
@@ -0,0 +1,51 @@
+Kernel driver adt7410
+=====================
+
+Supported chips:
+  * Analog Devices ADT7410
+    Prefix: 'adt7410'
+    Addresses scanned: I2C 0x48 - 0x4B
+    Datasheet: Publicly available at the Analog Devices website
+               http://www.analog.com/static/imported-files/data_sheets/ADT7410.pdf
+
+Author: Hartmut Knaack <knaack.h@gmx.de>
+
+Description
+-----------
+
+The ADT7410 is a temperature sensor with rated temperature range of -55°C to
++150°C. It has a high accuracy of +/-0.5°C and can be operated at a resolution
+of 13 bits (0.0625°C) or 16 bits (0.0078°C). The sensor provides an INT pin to
+indicate that a minimum or maximum temperature set point has been exceeded, as
+well as a critical temperature (CT) pin to indicate that the critical
+temperature set point has been exceeded. Both pins can be set up with a common
+hysteresis of 0°C - 15°C and a fault queue, ranging from 1 to 4 events. Both
+pins can individually set to be active-low or active-high, while the whole
+device can either run in comparator mode or interrupt mode. The ADT7410
+supports continous temperature sampling, as well as sampling one temperature
+value per second or even justget one sample on demand for power saving.
+Besides, it can completely power down its ADC, if power management is
+required.
+
+Configuration Notes
+-------------------
+
+Since the device uses one hysteresis value, which is an offset to minimum,
+maximum and critical temperature, it can only be set for temp#_max_hyst.
+However, temp#_min_hyst and temp#_crit_hyst show their corresponding
+hysteresis.
+The device is set to 16 bit resolution and comparator mode.
+
+sysfs-Interface
+---------------
+
+temp#_input		- temperature input
+temp#_min		- temperature minimum setpoint
+temp#_max		- temperature maximum setpoint
+temp#_crit		- critical temperature setpoint
+temp#_min_hyst		- hysteresis for temperature minimum (read-only)
+temp#_max_hyst		- hysteresis for temperature maximum (read/write)
+temp#_crit_hyst		- hysteresis for critical temperature (read-only)
+temp#_min_alarm		- temperature minimum alarm flag
+temp#_max_alarm		- temperature maximum alarm flag
+temp#_crit_alarm	- critical temperature alarm flag
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index b0a2e4c37e12..f50cb440575d 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -179,6 +179,16 @@ config SENSORS_ADM9240
 	  This driver can also be built as a module.  If so, the module
 	  will be called adm9240.
 
+config SENSORS_ADT7410
+	tristate "Analog Devices ADT7410"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for the Analog Devices
+	  ADT7410 temperature monitoring chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called adt7410.
+
 config SENSORS_ADT7411
 	tristate "Analog Devices ADT7411"
 	depends on I2C && EXPERIMENTAL
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 7aa98119c4ab..8b3d4382f61e 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_SENSORS_ADM9240)	+= adm9240.o
 obj-$(CONFIG_SENSORS_ADS1015)	+= ads1015.o
 obj-$(CONFIG_SENSORS_ADS7828)	+= ads7828.o
 obj-$(CONFIG_SENSORS_ADS7871)	+= ads7871.o
+obj-$(CONFIG_SENSORS_ADT7410)	+= adt7410.o
 obj-$(CONFIG_SENSORS_ADT7411)	+= adt7411.o
 obj-$(CONFIG_SENSORS_ADT7462)	+= adt7462.o
 obj-$(CONFIG_SENSORS_ADT7470)	+= adt7470.o
diff --git a/drivers/hwmon/adt7410.c b/drivers/hwmon/adt7410.c
new file mode 100644
index 000000000000..f8606dff3d1c
--- /dev/null
+++ b/drivers/hwmon/adt7410.c
@@ -0,0 +1,459 @@
+/*
+ * adt7410.c - Part of lm_sensors, Linux kernel modules for hardware
+ *	 monitoring
+ * This driver handles the ADT7410 and compatible digital temperature sensors.
+ * Hartmut Knaack <knaack.h@gmx.de> 2012-07-22
+ * based on lm75.c by Frodo Looijaard <frodol@dds.nl>
+ * and adt7410.c from iio-staging by Sonic Zhang <sonic.zhang@analog.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#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/delay.h>
+
+/*
+ * ADT7410 registers definition
+ */
+
+#define ADT7410_TEMPERATURE		0
+#define ADT7410_STATUS			2
+#define ADT7410_CONFIG			3
+#define ADT7410_T_ALARM_HIGH		4
+#define ADT7410_T_ALARM_LOW		6
+#define ADT7410_T_CRIT			8
+#define ADT7410_T_HYST			0xA
+
+/*
+ * ADT7410 status
+ */
+#define ADT7410_STAT_T_LOW		(1 << 4)
+#define ADT7410_STAT_T_HIGH		(1 << 5)
+#define ADT7410_STAT_T_CRIT		(1 << 6)
+#define ADT7410_STAT_NOT_RDY		(1 << 7)
+
+/*
+ * ADT7410 config
+ */
+#define ADT7410_FAULT_QUEUE_MASK	(1 << 0 | 1 << 1)
+#define ADT7410_CT_POLARITY		(1 << 2)
+#define ADT7410_INT_POLARITY		(1 << 3)
+#define ADT7410_EVENT_MODE		(1 << 4)
+#define ADT7410_MODE_MASK		(1 << 5 | 1 << 6)
+#define ADT7410_FULL			(0 << 5 | 0 << 6)
+#define ADT7410_PD			(1 << 5 | 1 << 6)
+#define ADT7410_RESOLUTION		(1 << 7)
+
+/*
+ * ADT7410 masks
+ */
+#define ADT7410_T13_VALUE_MASK			0xFFF8
+#define ADT7410_T_HYST_MASK			0xF
+
+/* straight from the datasheet */
+#define ADT7410_TEMP_MIN (-55000)
+#define ADT7410_TEMP_MAX 150000
+
+enum adt7410_type {		/* keep sorted in alphabetical order */
+	adt7410,
+};
+
+/* Addresses scanned */
+static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
+					I2C_CLIENT_END };
+
+static const u8 ADT7410_REG_TEMP[4] = {
+	ADT7410_TEMPERATURE,		/* input */
+	ADT7410_T_ALARM_HIGH,		/* high */
+	ADT7410_T_ALARM_LOW,		/* low */
+	ADT7410_T_CRIT,			/* critical */
+};
+
+/* Each client has this additional data */
+struct adt7410_data {
+	struct device		*hwmon_dev;
+	struct mutex		update_lock;
+	u8			config;
+	u8			oldconfig;
+	bool			valid;		/* true if registers valid */
+	unsigned long		last_updated;	/* In jiffies */
+	s16			temp[4];	/* Register values,
+						   0 = input
+						   1 = high
+						   2 = low
+						   3 = critical */
+	u8			hyst;		/* hysteresis offset */
+};
+
+/*
+ * adt7410 register access by I2C
+ */
+static int adt7410_temp_ready(struct i2c_client *client)
+{
+	int i, status;
+
+	for (i = 0; i < 6; i++) {
+		status = i2c_smbus_read_byte_data(client, ADT7410_STATUS);
+		if (status < 0)
+			return status;
+		if (!(status & ADT7410_STAT_NOT_RDY))
+			return 0;
+		msleep(60);
+	}
+	return -ETIMEDOUT;
+}
+
+static struct adt7410_data *adt7410_update_device(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct adt7410_data *data = i2c_get_clientdata(client);
+	struct adt7410_data *ret = data;
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
+	    || !data->valid) {
+		int i, status;
+
+		dev_dbg(&client->dev, "Starting update\n");
+
+		status = adt7410_temp_ready(client); /* check for new value */
+		if (unlikely(status)) {
+			ret = ERR_PTR(status);
+			goto abort;
+		}
+		for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
+			status = i2c_smbus_read_word_swapped(client,
+							ADT7410_REG_TEMP[i]);
+			if (unlikely(status < 0)) {
+				dev_dbg(dev,
+					"Failed to read value: reg %d, error %d\n",
+					ADT7410_REG_TEMP[i], status);
+				ret = ERR_PTR(status);
+				goto abort;
+			}
+			data->temp[i] = status;
+		}
+		status = i2c_smbus_read_byte_data(client, ADT7410_T_HYST);
+		if (unlikely(status < 0)) {
+			dev_dbg(dev,
+				"Failed to read value: reg %d, error %d\n",
+				ADT7410_T_HYST, status);
+			ret = ERR_PTR(status);
+			goto abort;
+		}
+		data->hyst = status;
+		data->last_updated = jiffies;
+		data->valid = true;
+	}
+
+abort:
+	mutex_unlock(&data->update_lock);
+	return ret;
+}
+
+static s16 ADT7410_TEMP_TO_REG(long temp)
+{
+	return DIV_ROUND_CLOSEST(SENSORS_LIMIT(temp, ADT7410_TEMP_MIN,
+					       ADT7410_TEMP_MAX) * 128, 1000);
+}
+
+static int ADT7410_REG_TO_TEMP(struct adt7410_data *data, s16 reg)
+{
+	/* in 13 bit mode, bits 0-2 are status flags - mask them out */
+	if (!(data->config & ADT7410_RESOLUTION))
+		reg &= ADT7410_T13_VALUE_MASK;
+	/*
+	 * temperature is stored in twos complement format, in steps of
+	 * 1/128°C
+	 */
+	return DIV_ROUND_CLOSEST(reg * 1000, 128);
+}
+
+/*-----------------------------------------------------------------------*/
+
+/* sysfs attributes for hwmon */
+
+static ssize_t adt7410_show_temp(struct device *dev,
+				 struct device_attribute *da, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct adt7410_data *data = adt7410_update_device(dev);
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	return sprintf(buf, "%d\n", ADT7410_REG_TO_TEMP(data,
+		       data->temp[attr->index]));
+}
+
+static ssize_t adt7410_set_temp(struct device *dev,
+				struct device_attribute *da,
+				const char *buf, size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct i2c_client *client = to_i2c_client(dev);
+	struct adt7410_data *data = i2c_get_clientdata(client);
+	int nr = attr->index;
+	long temp;
+	int ret;
+
+	ret = kstrtol(buf, 10, &temp);
+	if (ret)
+		return ret;
+
+	mutex_lock(&data->update_lock);
+	data->temp[nr] = ADT7410_TEMP_TO_REG(temp);
+	ret = i2c_smbus_write_word_swapped(client, ADT7410_REG_TEMP[nr],
+					   data->temp[nr]);
+	if (ret)
+		count = ret;
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+static ssize_t adt7410_show_t_hyst(struct device *dev,
+				   struct device_attribute *da,
+				   char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct adt7410_data *data = adt7410_update_device(dev);
+	int nr = attr->index;
+	int hyst = (data->hyst & ADT7410_T_HYST_MASK) * 1000;
+
+	/*
+	 * hysteresis is stored as a 4 bit offset in the device, convert it
+	 * to an absolute value
+	 */
+	if (nr == 2)	/* min has positive offset, others have negative */
+		hyst = -hyst;
+	return sprintf(buf, "%d\n",
+		       ADT7410_REG_TO_TEMP(data, data->temp[nr]) - hyst);
+}
+
+static ssize_t adt7410_set_t_hyst(struct device *dev,
+				  struct device_attribute *da,
+				  const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct adt7410_data *data = i2c_get_clientdata(client);
+	int limit, ret;
+	long hyst;
+
+	ret = kstrtol(buf, 10, &hyst);
+	if (ret)
+		return ret;
+	/* convert absolute hysteresis value to a 4 bit delta value */
+	limit = ADT7410_REG_TO_TEMP(data, data->temp[1]);
+	hyst = SENSORS_LIMIT(hyst, ADT7410_TEMP_MIN, ADT7410_TEMP_MAX);
+	data->hyst = SENSORS_LIMIT(DIV_ROUND_CLOSEST(limit - hyst, 1000),
+				   0, ADT7410_T_HYST_MASK);
+	ret = i2c_smbus_write_byte_data(client, ADT7410_T_HYST, data->hyst);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t adt7410_show_alarm(struct device *dev,
+				  struct device_attribute *da,
+				  char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(client, ADT7410_STATUS);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", !!(ret & attr->index));
+}
+
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, adt7410_show_temp, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
+			  adt7410_show_temp, adt7410_set_temp, 1);
+static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
+			  adt7410_show_temp, adt7410_set_temp, 2);
+static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
+			  adt7410_show_temp, adt7410_set_temp, 3);
+static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
+			  adt7410_show_t_hyst, adt7410_set_t_hyst, 1);
+static SENSOR_DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
+			  adt7410_show_t_hyst, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IRUGO,
+			  adt7410_show_t_hyst, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, adt7410_show_alarm,
+			  NULL, ADT7410_STAT_T_LOW);
+static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, adt7410_show_alarm,
+			  NULL, ADT7410_STAT_T_HIGH);
+static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, adt7410_show_alarm,
+			  NULL, ADT7410_STAT_T_CRIT);
+
+static struct attribute *adt7410_attributes[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_max.dev_attr.attr,
+	&sensor_dev_attr_temp1_min.dev_attr.attr,
+	&sensor_dev_attr_temp1_crit.dev_attr.attr,
+	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
+	&sensor_dev_attr_temp1_min_hyst.dev_attr.attr,
+	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
+	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group adt7410_group = {
+	.attrs = adt7410_attributes,
+};
+
+/*-----------------------------------------------------------------------*/
+
+/* device probe and removal */
+
+static int adt7410_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct adt7410_data *data;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter,
+			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
+		return -ENODEV;
+
+	data = devm_kzalloc(&client->dev, sizeof(struct adt7410_data),
+			    GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->update_lock);
+
+	/* configure as specified */
+	ret = i2c_smbus_read_byte_data(client, ADT7410_CONFIG);
+	if (ret < 0) {
+		dev_dbg(&client->dev, "Can't read config? %d\n", ret);
+		return ret;
+	}
+	data->oldconfig = ret;
+	/*
+	 * Set to 16 bit resolution, continous conversion and comparator mode.
+	 */
+	data->config = ret | ADT7410_FULL | ADT7410_RESOLUTION |
+			ADT7410_EVENT_MODE;
+	if (data->config != data->oldconfig) {
+		ret = i2c_smbus_write_byte_data(client, ADT7410_CONFIG,
+						data->config);
+		if (ret)
+			return ret;
+	}
+	dev_dbg(&client->dev, "Config %02x\n", data->config);
+
+	/* Register sysfs hooks */
+	ret = sysfs_create_group(&client->dev.kobj, &adt7410_group);
+	if (ret)
+		goto exit_restore;
+
+	data->hwmon_dev = hwmon_device_register(&client->dev);
+	if (IS_ERR(data->hwmon_dev)) {
+		ret = PTR_ERR(data->hwmon_dev);
+		goto exit_remove;
+	}
+
+	dev_info(&client->dev, "sensor '%s'\n", client->name);
+
+	return 0;
+
+exit_remove:
+	sysfs_remove_group(&client->dev.kobj, &adt7410_group);
+exit_restore:
+	i2c_smbus_write_byte_data(client, ADT7410_CONFIG, data->oldconfig);
+	return ret;
+}
+
+static int adt7410_remove(struct i2c_client *client)
+{
+	struct adt7410_data *data = i2c_get_clientdata(client);
+
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&client->dev.kobj, &adt7410_group);
+	if (data->oldconfig != data->config)
+		i2c_smbus_write_byte_data(client, ADT7410_CONFIG,
+					  data->oldconfig);
+	return 0;
+}
+
+static const struct i2c_device_id adt7410_ids[] = {
+	{ "adt7410", adt7410, },
+	{ /* LIST END */ }
+};
+MODULE_DEVICE_TABLE(i2c, adt7410_ids);
+
+#ifdef CONFIG_PM
+static int adt7410_suspend(struct device *dev)
+{
+	int ret;
+	struct i2c_client *client = to_i2c_client(dev);
+	struct adt7410_data *data = i2c_get_clientdata(client);
+
+	ret = i2c_smbus_write_byte_data(client, ADT7410_CONFIG,
+					data->config | ADT7410_PD);
+	return ret;
+}
+
+static int adt7410_resume(struct device *dev)
+{
+	int ret;
+	struct i2c_client *client = to_i2c_client(dev);
+	struct adt7410_data *data = i2c_get_clientdata(client);
+
+	ret = i2c_smbus_write_byte_data(client, ADT7410_CONFIG, data->config);
+	return ret;
+}
+
+static const struct dev_pm_ops adt7410_dev_pm_ops = {
+	.suspend	= adt7410_suspend,
+	.resume		= adt7410_resume,
+};
+#define ADT7410_DEV_PM_OPS (&adt7410_dev_pm_ops)
+#else
+#define ADT7410_DEV_PM_OPS NULL
+#endif /* CONFIG_PM */
+
+static struct i2c_driver adt7410_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.driver = {
+		.name	= "adt7410",
+		.pm	= ADT7410_DEV_PM_OPS,
+	},
+	.probe		= adt7410_probe,
+	.remove		= adt7410_remove,
+	.id_table	= adt7410_ids,
+	.address_list	= normal_i2c,
+};
+
+module_i2c_driver(adt7410_driver);
+
+MODULE_AUTHOR("Hartmut Knaack");
+MODULE_DESCRIPTION("ADT7410 driver");
+MODULE_LICENSE("GPL");