hwmon: ad7414 driver
Driver for the Analog Devices AD7414 temperature monitoring chip.
Signed-off-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/hwmon/ad7414.c b/drivers/hwmon/ad7414.c
new file mode 100644
index 0000000..ce8d94f
--- /dev/null
+++ b/drivers/hwmon/ad7414.c
@@ -0,0 +1,268 @@
+/*
+ * An hwmon driver for the Analog Devices AD7414
+ *
+ * Copyright 2006 Stefan Roese <sr at denx.de>, DENX Software Engineering
+ *
+ * Copyright (c) 2008 PIKA Technologies
+ * Sean MacLennan <smaclennan@pikatech.com>
+ *
+ * Copyright (c) 2008 Spansion Inc.
+ * Frank Edelhaeuser <frank.edelhaeuser at spansion.com>
+ * (converted to "new style" I2C driver model, removed checkpatch.pl warnings)
+ *
+ * Based on ad7418.c
+ * Copyright 2006 Tower Technologies, Alessandro Zummo <a.zummo at towertech.it>
+ *
+ * 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 <linux/module.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>
+
+
+/* AD7414 registers */
+#define AD7414_REG_TEMP 0x00
+#define AD7414_REG_CONF 0x01
+#define AD7414_REG_T_HIGH 0x02
+#define AD7414_REG_T_LOW 0x03
+
+static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW };
+
+struct ad7414_data {
+ struct device *hwmon_dev;
+ struct mutex lock; /* atomic read data updates */
+ char valid; /* !=0 if following fields are valid */
+ unsigned long next_update; /* In jiffies */
+ s16 temp_input; /* Register values */
+ s8 temps[ARRAY_SIZE(AD7414_REG_LIMIT)];
+};
+
+/* REG: (0.25C/bit, two's complement) << 6 */
+static inline int ad7414_temp_from_reg(s16 reg)
+{
+ /* use integer division instead of equivalent right shift to
+ * guarantee arithmetic shift and preserve the sign
+ */
+ return ((int)reg / 64) * 250;
+}
+
+static inline int ad7414_read(struct i2c_client *client, u8 reg)
+{
+ if (reg == AD7414_REG_TEMP) {
+ int value = i2c_smbus_read_word_data(client, reg);
+ return (value < 0) ? value : swab16(value);
+ } else
+ return i2c_smbus_read_byte_data(client, reg);
+}
+
+static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value)
+{
+ return i2c_smbus_write_byte_data(client, reg, value);
+}
+
+struct ad7414_data *ad7414_update_device(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct ad7414_data *data = i2c_get_clientdata(client);
+
+ mutex_lock(&data->lock);
+
+ if (time_after(jiffies, data->next_update) || !data->valid) {
+ int value, i;
+
+ dev_dbg(&client->dev, "starting ad7414 update\n");
+
+ value = ad7414_read(client, AD7414_REG_TEMP);
+ if (value < 0)
+ dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n",
+ value);
+ else
+ data->temp_input = value;
+
+ for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) {
+ value = ad7414_read(client, AD7414_REG_LIMIT[i]);
+ if (value < 0)
+ dev_dbg(&client->dev, "AD7414 reg %d err %d\n",
+ AD7414_REG_LIMIT[i], value);
+ else
+ data->temps[i] = value;
+ }
+
+ data->next_update = jiffies + HZ + HZ / 2;
+ data->valid = 1;
+ }
+
+ mutex_unlock(&data->lock);
+
+ return data;
+}
+
+static ssize_t show_temp_input(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct ad7414_data *data = ad7414_update_device(dev);
+ return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input));
+}
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
+
+static ssize_t show_max_min(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ int index = to_sensor_dev_attr(attr)->index;
+ struct ad7414_data *data = ad7414_update_device(dev);
+ return sprintf(buf, "%d\n", data->temps[index] * 1000);
+}
+
+static ssize_t set_max_min(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct ad7414_data *data = i2c_get_clientdata(client);
+ int index = to_sensor_dev_attr(attr)->index;
+ u8 reg = AD7414_REG_LIMIT[index];
+ long temp = simple_strtol(buf, NULL, 10);
+
+ temp = SENSORS_LIMIT(temp, -40000, 85000);
+ temp = (temp + (temp < 0 ? -500 : 500)) / 1000;
+
+ mutex_lock(&data->lock);
+ data->temps[index] = temp;
+ ad7414_write(client, reg, temp);
+ mutex_unlock(&data->lock);
+ return count;
+}
+
+static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
+ show_max_min, set_max_min, 0);
+static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
+ show_max_min, set_max_min, 1);
+
+static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ int bitnr = to_sensor_dev_attr(attr)->index;
+ struct ad7414_data *data = ad7414_update_device(dev);
+ int value = (data->temp_input >> bitnr) & 1;
+ return sprintf(buf, "%d\n", value);
+}
+
+static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);
+
+static struct attribute *ad7414_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_max_alarm.dev_attr.attr,
+ &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
+ NULL
+};
+
+static const struct attribute_group ad7414_group = {
+ .attrs = ad7414_attributes,
+};
+
+static int ad7414_probe(struct i2c_client *client,
+ const struct i2c_device_id *dev_id)
+{
+ struct ad7414_data *data;
+ int conf;
+ int err = 0;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+ I2C_FUNC_SMBUS_READ_WORD_DATA))
+ goto exit;
+
+ data = kzalloc(sizeof(struct ad7414_data), GFP_KERNEL);
+ if (!data) {
+ err = -ENOMEM;
+ goto exit;
+ }
+
+ i2c_set_clientdata(client, data);
+ mutex_init(&data->lock);
+
+ dev_info(&client->dev, "chip found\n");
+
+ /* Make sure the chip is powered up. */
+ conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
+ if (conf < 0)
+ dev_warn(&client->dev,
+ "ad7414_probe unable to read config register.\n");
+ else {
+ conf &= ~(1 << 7);
+ i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
+ }
+
+ /* Register sysfs hooks */
+ err = sysfs_create_group(&client->dev.kobj, &ad7414_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);
+ goto exit_remove;
+ }
+
+ return 0;
+
+exit_remove:
+ sysfs_remove_group(&client->dev.kobj, &ad7414_group);
+exit_free:
+ kfree(data);
+exit:
+ return err;
+}
+
+static int __devexit ad7414_remove(struct i2c_client *client)
+{
+ struct ad7414_data *data = i2c_get_clientdata(client);
+
+ hwmon_device_unregister(data->hwmon_dev);
+ sysfs_remove_group(&client->dev.kobj, &ad7414_group);
+ kfree(data);
+ return 0;
+}
+
+static const struct i2c_device_id ad7414_id[] = {
+ { "ad7414", 0 },
+ {}
+};
+
+static struct i2c_driver ad7414_driver = {
+ .driver = {
+ .name = "ad7414",
+ },
+ .probe = ad7414_probe,
+ .remove = __devexit_p(ad7414_remove),
+ .id_table = ad7414_id,
+};
+
+static int __init ad7414_init(void)
+{
+ return i2c_add_driver(&ad7414_driver);
+}
+module_init(ad7414_init);
+
+static void __exit ad7414_exit(void)
+{
+ i2c_del_driver(&ad7414_driver);
+}
+module_exit(ad7414_exit);
+
+MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
+ "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
+
+MODULE_DESCRIPTION("AD7414 driver");
+MODULE_LICENSE("GPL");