hwmon: Add driver for Texas Instruments TMP421/422/423 sensor chips

Add support for Texas Instruments TMP421/422/423 temperature sensor IC.

TI's TMP421/422/423 are I2C temperature sensor chips. These chips are
similar to TI's TMP401/411 chips, but with reduced functionality (only
temperature measurement). The chips have one local sensor and up to
three (TMP423) remote sensors.
Signed-off-by: Andre Prendel <andre.prendel@gmx.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/hwmon/Kconfig

@@ -814,6 +814,16 @@ config SENSORS_TMP401
 	  This driver can also be built as a module.  If so, the module
 	  will be called tmp401.
 
+config SENSORS_TMP421
+	tristate "Texas Instruments TMP421 and compatible"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for Texas Instruments TMP421,
+	  TMP422 and TMP423 temperature sensor chips.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called tmp421.
+
 config SENSORS_VIA686A
 	tristate "VIA686A"
 	depends on PCI

drivers/hwmon/Makefile

@@ -84,6 +84,7 @@ obj-$(CONFIG_SENSORS_SMSC47M1)	+= smsc47m1.o
 obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
 obj-$(CONFIG_SENSORS_THMC50)	+= thmc50.o
 obj-$(CONFIG_SENSORS_TMP401)	+= tmp401.o
+obj-$(CONFIG_SENSORS_TMP421)	+= tmp421.o
 obj-$(CONFIG_SENSORS_VIA686A)	+= via686a.o
 obj-$(CONFIG_SENSORS_VT1211)	+= vt1211.o
 obj-$(CONFIG_SENSORS_VT8231)	+= vt8231.o

drivers/hwmon/tmp421.c

+/* tmp421.c
+ *
+ * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
+ * Preliminary support by:
+ * Melvin Rook, Raymond Ng
+ *
+ * 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.
+ */
+
+/*
+ * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
+ * Supported models: TMP421, TMP422, TMP423
+ */
+
+#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/sysfs.h>
+
+/* Addresses to scan */
+static unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
+				       I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD_3(tmp421, tmp422, tmp423);
+
+/* The TMP421 registers */
+#define TMP421_CONFIG_REG_1			0x09
+#define TMP421_CONVERSION_RATE_REG		0x0B
+#define TMP421_MANUFACTURER_ID_REG		0xFE
+#define TMP421_DEVICE_ID_REG			0xFF
+
+static const u8 TMP421_TEMP_MSB[4]		= { 0x00, 0x01, 0x02, 0x03 };
+static const u8 TMP421_TEMP_LSB[4]		= { 0x10, 0x11, 0x12, 0x13 };
+
+/* Flags */
+#define TMP421_CONFIG_SHUTDOWN			0x40
+#define TMP421_CONFIG_RANGE			0x04
+
+/* Manufacturer / Device ID's */
+#define TMP421_MANUFACTURER_ID			0x55
+#define TMP421_DEVICE_ID			0x21
+#define TMP422_DEVICE_ID			0x22
+#define TMP423_DEVICE_ID			0x23
+
+static const struct i2c_device_id tmp421_id[] = {
+	{ "tmp421", tmp421 },
+	{ "tmp422", tmp422 },
+	{ "tmp423", tmp423 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tmp421_id);
+
+struct tmp421_data {
+	struct device *hwmon_dev;
+	struct mutex update_lock;
+	char valid;
+	unsigned long last_updated;
+	int kind;
+	u8 config;
+	s16 temp[4];
+};
+
+static int temp_from_s16(s16 reg)
+{
+	int temp = reg;
+
+	return (temp * 1000 + 128) / 256;
+}
+
+static int temp_from_u16(u16 reg)
+{
+	int temp = reg;
+
+	/* Add offset for extended temperature range. */
+	temp -= 64 * 256;
+
+	return (temp * 1000 + 128) / 256;
+}
+
+static struct tmp421_data *tmp421_update_device(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct tmp421_data *data = i2c_get_clientdata(client);
+	int i;
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
+		data->config = i2c_smbus_read_byte_data(client,
+			TMP421_CONFIG_REG_1);
+
+		for (i = 0; i <= data->kind; i++) {
+			data->temp[i] = i2c_smbus_read_byte_data(client,
+				TMP421_TEMP_MSB[i]) << 8;
+			data->temp[i] |= i2c_smbus_read_byte_data(client,
+				TMP421_TEMP_LSB[i]);
+		}
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+
+	mutex_unlock(&data->update_lock);
+
+	return data;
+}
+
+static ssize_t show_temp_value(struct device *dev,
+			       struct device_attribute *devattr, char *buf)
+{
+	int index = to_sensor_dev_attr(devattr)->index;
+	struct tmp421_data *data = tmp421_update_device(dev);
+	int temp;
+
+	mutex_lock(&data->update_lock);
+	if (data->config & TMP421_CONFIG_RANGE)
+		temp = temp_from_u16(data->temp[index]);
+	else
+		temp = temp_from_s16(data->temp[index]);
+	mutex_unlock(&data->update_lock);
+
+	return sprintf(buf, "%d\n", temp);
+}
+
+static ssize_t show_fault(struct device *dev,
+			  struct device_attribute *devattr, char *buf)
+{
+	int index = to_sensor_dev_attr(devattr)->index;
+	struct tmp421_data *data = tmp421_update_device(dev);
+
+	/*
+	 * The OPEN bit signals a fault. This is bit 0 of the temperature
+	 * register (low byte).
+	 */
+	if (data->temp[index] & 0x01)
+		return sprintf(buf, "1\n");
+	else
+		return sprintf(buf, "0\n");
+}
+
+static mode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
+				int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct tmp421_data *data = dev_get_drvdata(dev);
+	struct device_attribute *devattr;
+	unsigned int index;
+
+	devattr = container_of(a, struct device_attribute, attr);
+	index = to_sensor_dev_attr(devattr)->index;
+
+	if (data->kind > index)
+		return a->mode;
+
+	return 0;
+}
+
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_value, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_value, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp_value, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp_value, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
+
+static struct attribute *tmp421_attr[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp2_input.dev_attr.attr,
+	&sensor_dev_attr_temp2_fault.dev_attr.attr,
+	&sensor_dev_attr_temp3_input.dev_attr.attr,
+	&sensor_dev_attr_temp3_fault.dev_attr.attr,
+	&sensor_dev_attr_temp4_input.dev_attr.attr,
+	&sensor_dev_attr_temp4_fault.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group tmp421_group = {
+	.attrs = tmp421_attr,
+	.is_visible = tmp421_is_visible,
+};
+
+static int tmp421_init_client(struct i2c_client *client)
+{
+	int config, config_orig;
+
+	/* Set the conversion rate to 2 Hz */
+	i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
+
+	/* Start conversions (disable shutdown if necessary) */
+	config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
+	if (config < 0) {
+		dev_err(&client->dev, "Could not read configuration"
+			 " register (%d)\n", config);
+		return -ENODEV;
+	}
+
+	config_orig = config;
+	config &= ~TMP421_CONFIG_SHUTDOWN;
+
+	if (config != config_orig) {
+		dev_info(&client->dev, "Enable monitoring chip\n");
+		i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
+	}
+
+	return 0;
+}
+
+static int tmp421_detect(struct i2c_client *client, int kind,
+			 struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	const char *names[] = { "TMP421", "TMP422", "TMP423" };
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	if (kind <= 0) {
+		u8 reg;
+
+		reg = i2c_smbus_read_byte_data(client,
+					       TMP421_MANUFACTURER_ID_REG);
+		if (reg != TMP421_MANUFACTURER_ID)
+			return -ENODEV;
+
+		reg = i2c_smbus_read_byte_data(client,
+					       TMP421_DEVICE_ID_REG);
+		switch (reg) {
+		case TMP421_DEVICE_ID:
+			kind = tmp421;
+			break;
+		case TMP422_DEVICE_ID:
+			kind = tmp422;
+			break;
+		case TMP423_DEVICE_ID:
+			kind = tmp423;
+			break;
+		default:
+			return -ENODEV;
+		}
+	}
+	strlcpy(info->type, tmp421_id[kind - 1].name, I2C_NAME_SIZE);
+	dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
+		 names[kind - 1], client->addr);
+
+	return 0;
+}
+
+static int tmp421_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct tmp421_data *data;
+	int err;
+
+	data = kzalloc(sizeof(struct tmp421_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->update_lock);
+	data->kind = id->driver_data;
+
+	err = tmp421_init_client(client);
+	if (err)
+		goto exit_free;
+
+	err = sysfs_create_group(&client->dev.kobj, &tmp421_group);
+	if (err)
+		goto exit_free;
+
+	data->hwmon_dev = hwmon_device_register(&client->dev);
+	if (IS_ERR(data->hwmon_dev)) {
+		err = PTR_ERR(data->hwmon_dev);
+		data->hwmon_dev = NULL;
+		goto exit_remove;
+	}
+	return 0;
+
+exit_remove:
+	sysfs_remove_group(&client->dev.kobj, &tmp421_group);
+
+exit_free:
+	i2c_set_clientdata(client, NULL);
+	kfree(data);
+
+	return err;
+}
+
+static int tmp421_remove(struct i2c_client *client)
+{
+	struct tmp421_data *data = i2c_get_clientdata(client);
+
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&client->dev.kobj, &tmp421_group);
+
+	i2c_set_clientdata(client, NULL);
+	kfree(data);
+
+	return 0;
+}
+
+static struct i2c_driver tmp421_driver = {
+	.class = I2C_CLASS_HWMON,
+	.driver = {
+		.name	= "tmp421",
+	},
+	.probe = tmp421_probe,
+	.remove = tmp421_remove,
+	.id_table = tmp421_id,
+	.detect = tmp421_detect,
+	.address_data = &addr_data,
+};
+
+static int __init tmp421_init(void)
+{
+	return i2c_add_driver(&tmp421_driver);
+}
+
+static void __exit tmp421_exit(void)
+{
+	i2c_del_driver(&tmp421_driver);
+}
+
+MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
+MODULE_DESCRIPTION("Texas Instruments TMP421/422/423 temperature sensor"
+		   " driver");
+MODULE_LICENSE("GPL");
+
+module_init(tmp421_init);
+module_exit(tmp421_exit);