hwmon: Add driver for ADT7411 voltage and temperature sensor

Add basic support for the ADT7411. Reads out all conversion results (via I2C,
SPI yet missing) and allows some on-the-fly configuration. Tested with a
custom board.

Signed-off-by: Sascha Hauer <[e-mail]>
Signed-off-by: Wolfram Sang <[e-mail]>
Signed-off-by: Jean Delvare <[e-mail]>

Documentation/hwmon/adt7411

···
+Kernel driver adt7411
+=====================
+
+Supported chips:
+  * Analog Devices ADT7411
+    Prefix: 'adt7411'
+    Addresses scanned: 0x48, 0x4a, 0x4b
+    Datasheet: Publicly available at the Analog Devices website
+
+Author: Wolfram Sang (based on adt7470 by Darrick J. Wong)
+
+Description
+-----------
+
+This driver implements support for the Analog Devices ADT7411 chip. There may
+be other chips that implement this interface.
+
+The ADT7411 can use an I2C/SMBus compatible 2-wire interface or an
+SPI-compatible 4-wire interface. It provides a 10-bit analog to digital
+converter which measures 1 temperature, vdd and 8 input voltages. It has an
+internal temperature sensor, but an external one can also be connected (one
+loses 2 inputs then). There are high- and low-limit registers for all inputs.
+
+Check the datasheet for details.
+
+sysfs-Interface
+---------------
+
+in0_input	- vdd voltage input
+in[1-8]_input	- analog 1-8 input
+temp1_input	- temperature input
+
+Besides standard interfaces, this driver adds (0 = off, 1 = on):
+
+  adc_ref_vdd	- Use vdd as reference instead of 2.25 V
+  fast_sampling	- Sample at 22.5 kHz instead of 1.4 kHz, but drop filters
+  no_average	- Turn off averaging over 16 samples
+
+Notes
+-----
+
+SPI, external temperature sensor and limit registers are not supported yet.

drivers/hwmon/Kconfig

···
 	  This driver can also be built as a module.  If so, the module
 	  will be called adm9240.
 
+config SENSORS_ADT7411
+	tristate "Analog Devices ADT7411"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for the Analog Devices
+	  ADT7411 voltage and temperature monitoring chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called adt7411.
+
 config SENSORS_ADT7462
 	tristate "Analog Devices ADT7462"
 	depends on I2C && EXPERIMENTAL

drivers/hwmon/Makefile

···
 obj-$(CONFIG_SENSORS_ADM1031)	+= adm1031.o
 obj-$(CONFIG_SENSORS_ADM9240)	+= adm9240.o
 obj-$(CONFIG_SENSORS_ADS7828)	+= ads7828.o
+obj-$(CONFIG_SENSORS_ADT7411)	+= adt7411.o
 obj-$(CONFIG_SENSORS_ADT7462)	+= adt7462.o
 obj-$(CONFIG_SENSORS_ADT7470)	+= adt7470.o
 obj-$(CONFIG_SENSORS_ADT7473)	+= adt7473.o

drivers/hwmon/adt7411.c

···
+/*
+ *  Driver for the ADT7411 (I2C/SPI 8 channel 10 bit ADC & temperature-sensor)
+ *
+ *  Copyright (C) 2008, 2010 Pengutronix
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ *  TODO: SPI, support for external temperature sensor
+ * 	  use power-down mode for suspend?, interrupt handling?
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+
+#define ADT7411_REG_INT_TEMP_VDD_LSB		0x03
+#define ADT7411_REG_EXT_TEMP_AIN14_LSB		0x04
+#define ADT7411_REG_VDD_MSB			0x06
+#define ADT7411_REG_INT_TEMP_MSB		0x07
+#define ADT7411_REG_EXT_TEMP_AIN1_MSB		0x08
+
+#define ADT7411_REG_CFG1			0x18
+#define ADT7411_CFG1_START_MONITOR		(1 << 0)
+
+#define ADT7411_REG_CFG2			0x19
+#define ADT7411_CFG2_DISABLE_AVG		(1 << 5)
+
+#define ADT7411_REG_CFG3			0x1a
+#define ADT7411_CFG3_ADC_CLK_225		(1 << 0)
+#define ADT7411_CFG3_REF_VDD			(1 << 4)
+
+#define ADT7411_REG_DEVICE_ID			0x4d
+#define ADT7411_REG_MANUFACTURER_ID		0x4e
+
+#define ADT7411_DEVICE_ID			0x2
+#define ADT7411_MANUFACTURER_ID			0x41
+
+static const unsigned short normal_i2c[] = { 0x48, 0x4a, 0x4b, I2C_CLIENT_END };
+
+struct adt7411_data {
+	struct mutex device_lock;	/* for "atomic" device accesses */
+	unsigned long next_update;
+	int vref_cached;
+	bool ref_is_vdd;
+	struct device *hwmon_dev;
+};
+
+/*
+ * When reading a register containing (up to 4) lsb, all associated
+ * msb-registers get locked by the hardware. After _one_ of those msb is read,
+ * _all_ are unlocked. In order to use this locking correctly, reading lsb/msb
+ * is protected here with a mutex, too.
+ */
+static int adt7411_read_10_bit(struct i2c_client *client, u8 lsb_reg,
+				u8 msb_reg, u8 lsb_shift)
+{
+	struct adt7411_data *data = i2c_get_clientdata(client);
+	int val, tmp;
+
+	mutex_lock(&data->device_lock);
+
+	val = i2c_smbus_read_byte_data(client, lsb_reg);
+	if (val < 0)
+		goto exit_unlock;
+
+	tmp = (val >> lsb_shift) & 3;
+	val = i2c_smbus_read_byte_data(client, msb_reg);
+
+	if (val >= 0)
+		val = (val << 2) | tmp;
+
+ exit_unlock:
+	mutex_unlock(&data->device_lock);
+
+	return val;
+}
+
+static int adt7411_modify_bit(struct i2c_client *client, u8 reg, u8 bit,
+				bool flag)
+{
+	struct adt7411_data *data = i2c_get_clientdata(client);
+	int ret, val;
+
+	mutex_lock(&data->device_lock);
+
+	ret = i2c_smbus_read_byte_data(client, reg);
+	if (ret < 0)
+		goto exit_unlock;
+
+	if (flag)
+		val = ret | bit;
+	else
+		val = ret & ~bit;
+
+	ret = i2c_smbus_write_byte_data(client, reg, val);
+
+ exit_unlock:
+	mutex_unlock(&data->device_lock);
+	return ret;
+}
+
+static ssize_t adt7411_show_vdd(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int ret = adt7411_read_10_bit(client, ADT7411_REG_INT_TEMP_VDD_LSB,
+			ADT7411_REG_VDD_MSB, 2);
+
+	return ret < 0 ? ret : sprintf(buf, "%u\n", ret * 7000 / 1024);
+}
+
+static ssize_t adt7411_show_temp(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int val = adt7411_read_10_bit(client, ADT7411_REG_INT_TEMP_VDD_LSB,
+			ADT7411_REG_INT_TEMP_MSB, 0);
+
+	if (val < 0)
+		return val;
+
+	val = val & 0x200 ? val - 0x400 : val; /* 10 bit signed */
+
+	return sprintf(buf, "%d\n", val * 250);
+}
+
+static ssize_t adt7411_show_input(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	int nr = to_sensor_dev_attr(attr)->index;
+	struct i2c_client *client = to_i2c_client(dev);
+	struct adt7411_data *data = i2c_get_clientdata(client);
+	int val;
+	u8 lsb_reg, lsb_shift;
+
+	if (time_after_eq(jiffies, data->next_update)) {
+		val = i2c_smbus_read_byte_data(client, ADT7411_REG_CFG3);
+		if (val < 0)
+			return val;
+		data->ref_is_vdd = val & ADT7411_CFG3_REF_VDD;
+
+		if (data->ref_is_vdd) {
+			val = adt7411_read_10_bit(client,
+					ADT7411_REG_INT_TEMP_VDD_LSB,
+					ADT7411_REG_VDD_MSB, 2);
+			if (val < 0)
+				return val;
+
+			data->vref_cached = val * 7000 / 1024;
+		} else {
+			data->vref_cached = 2250;
+		}
+
+		data->next_update = jiffies + HZ;
+	}
+
+	lsb_reg = ADT7411_REG_EXT_TEMP_AIN14_LSB + (nr >> 2);
+	lsb_shift = 2 * (nr & 0x03);
+	val = adt7411_read_10_bit(client, lsb_reg,
+			ADT7411_REG_EXT_TEMP_AIN1_MSB + nr, lsb_shift);
+
+	return val < 0 ? val :
+			sprintf(buf, "%u\n", val * data->vref_cached / 1024);
+}
+
+static ssize_t adt7411_show_bit(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
+	struct i2c_client *client = to_i2c_client(dev);
+	int ret = i2c_smbus_read_byte_data(client, attr2->index);
+
+	return ret < 0 ? ret : sprintf(buf, "%u\n", !!(ret & attr2->nr));
+}
+
+static ssize_t adt7411_set_bit(struct device *dev,
+			       struct device_attribute *attr, const char *buf,
+			       size_t count)
+{
+	struct sensor_device_attribute_2 *s_attr2 = to_sensor_dev_attr_2(attr);
+	struct i2c_client *client = to_i2c_client(dev);
+	struct adt7411_data *data = i2c_get_clientdata(client);
+	int ret;
+	unsigned long flag;
+
+	ret = strict_strtoul(buf, 0, &flag);
+	if (ret || flag > 1)
+		return -EINVAL;
+
+	ret = adt7411_modify_bit(client, s_attr2->index, s_attr2->nr, flag);
+
+	/* force update */
+	data->next_update = jiffies;
+
+	return ret < 0 ? ret : count;
+}
+
+#define ADT7411_BIT_ATTR(__name, __reg, __bit) \
+	SENSOR_DEVICE_ATTR_2(__name, S_IRUGO | S_IWUSR, adt7411_show_bit, \
+	adt7411_set_bit, __bit, __reg)
+
+static DEVICE_ATTR(temp1_input, S_IRUGO, adt7411_show_temp, NULL);
+static DEVICE_ATTR(in0_input, S_IRUGO, adt7411_show_vdd, NULL);
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, adt7411_show_input, NULL, 0);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, adt7411_show_input, NULL, 1);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, adt7411_show_input, NULL, 2);
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, adt7411_show_input, NULL, 3);
+static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, adt7411_show_input, NULL, 4);
+static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, adt7411_show_input, NULL, 5);
+static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, adt7411_show_input, NULL, 6);
+static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, adt7411_show_input, NULL, 7);
+static ADT7411_BIT_ATTR(no_average, ADT7411_REG_CFG2, ADT7411_CFG2_DISABLE_AVG);
+static ADT7411_BIT_ATTR(fast_sampling, ADT7411_REG_CFG3, ADT7411_CFG3_ADC_CLK_225);
+static ADT7411_BIT_ATTR(adc_ref_vdd, ADT7411_REG_CFG3, ADT7411_CFG3_REF_VDD);
+
+static struct attribute *adt7411_attrs[] = {
+	&dev_attr_temp1_input.attr,
+	&dev_attr_in0_input.attr,
+	&sensor_dev_attr_in1_input.dev_attr.attr,
+	&sensor_dev_attr_in2_input.dev_attr.attr,
+	&sensor_dev_attr_in3_input.dev_attr.attr,
+	&sensor_dev_attr_in4_input.dev_attr.attr,
+	&sensor_dev_attr_in5_input.dev_attr.attr,
+	&sensor_dev_attr_in6_input.dev_attr.attr,
+	&sensor_dev_attr_in7_input.dev_attr.attr,
+	&sensor_dev_attr_in8_input.dev_attr.attr,
+	&sensor_dev_attr_no_average.dev_attr.attr,
+	&sensor_dev_attr_fast_sampling.dev_attr.attr,
+	&sensor_dev_attr_adc_ref_vdd.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group adt7411_attr_grp = {
+	.attrs = adt7411_attrs,
+};
+
+static int adt7411_detect(struct i2c_client *client,
+			  struct i2c_board_info *info)
+{
+	int val;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	val = i2c_smbus_read_byte_data(client, ADT7411_REG_MANUFACTURER_ID);
+	if (val < 0 || val != ADT7411_MANUFACTURER_ID) {
+		dev_dbg(&client->dev, "Wrong manufacturer ID. Got %d, "
+			"expected %d\n", val, ADT7411_MANUFACTURER_ID);
+		return -ENODEV;
+	}
+
+	val = i2c_smbus_read_byte_data(client, ADT7411_REG_DEVICE_ID);
+	if (val < 0 || val != ADT7411_DEVICE_ID) {
+		dev_dbg(&client->dev, "Wrong device ID. Got %d, "
+			"expected %d\n", val, ADT7411_DEVICE_ID);
+		return -ENODEV;
+	}
+
+	strlcpy(info->type, "adt7411", I2C_NAME_SIZE);
+
+	return 0;
+}
+
+static int __devinit adt7411_probe(struct i2c_client *client,
+				   const struct i2c_device_id *id)
+{
+	struct adt7411_data *data;
+	int ret;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->device_lock);
+
+	ret = adt7411_modify_bit(client, ADT7411_REG_CFG1,
+				 ADT7411_CFG1_START_MONITOR, 1);
+	if (ret < 0)
+		goto exit_free;
+
+	/* force update on first occasion */
+	data->next_update = jiffies;
+
+	ret = sysfs_create_group(&client->dev.kobj, &adt7411_attr_grp);
+	if (ret)
+		goto exit_free;
+
+	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, "successfully registered\n");
+
+	return 0;
+
+ exit_remove:
+	sysfs_remove_group(&client->dev.kobj, &adt7411_attr_grp);
+ exit_free:
+	i2c_set_clientdata(client, NULL);
+	kfree(data);
+	return ret;
+}
+
+static int __devexit adt7411_remove(struct i2c_client *client)
+{
+	struct adt7411_data *data = i2c_get_clientdata(client);
+
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&client->dev.kobj, &adt7411_attr_grp);
+	i2c_set_clientdata(client, NULL);
+	kfree(data);
+	return 0;
+}
+
+static const struct i2c_device_id adt7411_id[] = {
+	{ "adt7411", 0 },
+	{ }
+};
+
+static struct i2c_driver adt7411_driver = {
+	.driver		= {
+		.name		= "adt7411",
+	},
+	.probe  = adt7411_probe,
+	.remove	= __devexit_p(adt7411_remove),
+	.id_table = adt7411_id,
+	.detect = adt7411_detect,
+	.address_list = normal_i2c,
+	.class = I2C_CLASS_HWMON,
+};
+
+static int __init sensors_adt7411_init(void)
+{
+	return i2c_add_driver(&adt7411_driver);
+}
+module_init(sensors_adt7411_init)
+
+static void __exit sensors_adt7411_exit(void)
+{
+	i2c_del_driver(&adt7411_driver);
+}
+module_exit(sensors_adt7411_exit)
+
+MODULE_AUTHOR("Sascha Hauer <[e-mail]> and "
+	"Wolfram Sang <[e-mail]>");
+MODULE_DESCRIPTION("ADT7411 driver");
+MODULE_LICENSE("GPL v2");