/drivers/hwmon/ad7414.c

  1/*
  2 * An hwmon driver for the Analog Devices AD7414
  3 *
  4 * Copyright 2006 Stefan Roese <sr at denx.de>, DENX Software Engineering
  5 *
  6 * Copyright (c) 2008 PIKA Technologies
  7 *   Sean MacLennan <smaclennan@pikatech.com>
  8 *
  9 * Copyright (c) 2008 Spansion Inc.
 10 *   Frank Edelhaeuser <frank.edelhaeuser at spansion.com>
 11 *   (converted to "new style" I2C driver model, removed checkpatch.pl warnings)
 12 *
 13 * Based on ad7418.c
 14 * Copyright 2006 Tower Technologies, Alessandro Zummo <a.zummo at towertech.it>
 15 *
 16 * This program is free software; you can redistribute it and/or modify
 17 * it under the terms of the GNU General Public License as published by
 18 * the Free Software Foundation; either version 2 of the License, or
 19 * (at your option) any later version.
 20 */
 21
 22#include <linux/module.h>
 23#include <linux/jiffies.h>
 24#include <linux/i2c.h>
 25#include <linux/hwmon.h>
 26#include <linux/hwmon-sysfs.h>
 27#include <linux/err.h>
 28#include <linux/mutex.h>
 29#include <linux/sysfs.h>
 30#include <linux/slab.h>
 31
 32
 33/* AD7414 registers */
 34#define AD7414_REG_TEMP		0x00
 35#define AD7414_REG_CONF		0x01
 36#define AD7414_REG_T_HIGH	0x02
 37#define AD7414_REG_T_LOW	0x03
 38
 39static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW };
 40
 41struct ad7414_data {
 42	struct device		*hwmon_dev;
 43	struct mutex		lock;	/* atomic read data updates */
 44	char			valid;	/* !=0 if following fields are valid */
 45	unsigned long		next_update;	/* In jiffies */
 46	s16			temp_input;	/* Register values */
 47	s8			temps[ARRAY_SIZE(AD7414_REG_LIMIT)];
 48};
 49
 50/* REG: (0.25C/bit, two's complement) << 6 */
 51static inline int ad7414_temp_from_reg(s16 reg)
 52{
 53	/* use integer division instead of equivalent right shift to
 54	 * guarantee arithmetic shift and preserve the sign
 55	 */
 56	return ((int)reg / 64) * 250;
 57}
 58
 59static inline int ad7414_read(struct i2c_client *client, u8 reg)
 60{
 61	if (reg == AD7414_REG_TEMP) {
 62		int value = i2c_smbus_read_word_data(client, reg);
 63		return (value < 0) ? value : swab16(value);
 64	} else
 65		return i2c_smbus_read_byte_data(client, reg);
 66}
 67
 68static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value)
 69{
 70	return i2c_smbus_write_byte_data(client, reg, value);
 71}
 72
 73static struct ad7414_data *ad7414_update_device(struct device *dev)
 74{
 75	struct i2c_client *client = to_i2c_client(dev);
 76	struct ad7414_data *data = i2c_get_clientdata(client);
 77
 78	mutex_lock(&data->lock);
 79
 80	if (time_after(jiffies, data->next_update) || !data->valid) {
 81		int value, i;
 82
 83		dev_dbg(&client->dev, "starting ad7414 update\n");
 84
 85		value = ad7414_read(client, AD7414_REG_TEMP);
 86		if (value < 0)
 87			dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n",
 88				value);
 89		else
 90			data->temp_input = value;
 91
 92		for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) {
 93			value = ad7414_read(client, AD7414_REG_LIMIT[i]);
 94			if (value < 0)
 95				dev_dbg(&client->dev, "AD7414 reg %d err %d\n",
 96					AD7414_REG_LIMIT[i], value);
 97			else
 98				data->temps[i] = value;
 99		}
100
101		data->next_update = jiffies + HZ + HZ / 2;
102		data->valid = 1;
103	}
104
105	mutex_unlock(&data->lock);
106
107	return data;
108}
109
110static ssize_t show_temp_input(struct device *dev,
111			       struct device_attribute *attr, char *buf)
112{
113	struct ad7414_data *data = ad7414_update_device(dev);
114	return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input));
115}
116static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
117
118static ssize_t show_max_min(struct device *dev, struct device_attribute *attr,
119			  char *buf)
120{
121	int index = to_sensor_dev_attr(attr)->index;
122	struct ad7414_data *data = ad7414_update_device(dev);
123	return sprintf(buf, "%d\n", data->temps[index] * 1000);
124}
125
126static ssize_t set_max_min(struct device *dev,
127			   struct device_attribute *attr,
128			   const char *buf, size_t count)
129{
130	struct i2c_client *client = to_i2c_client(dev);
131	struct ad7414_data *data = i2c_get_clientdata(client);
132	int index = to_sensor_dev_attr(attr)->index;
133	u8 reg = AD7414_REG_LIMIT[index];
134	long temp = simple_strtol(buf, NULL, 10);
135
136	temp = SENSORS_LIMIT(temp, -40000, 85000);
137	temp = (temp + (temp < 0 ? -500 : 500)) / 1000;
138
139	mutex_lock(&data->lock);
140	data->temps[index] = temp;
141	ad7414_write(client, reg, temp);
142	mutex_unlock(&data->lock);
143	return count;
144}
145
146static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
147			  show_max_min, set_max_min, 0);
148static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
149			  show_max_min, set_max_min, 1);
150
151static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
152			  char *buf)
153{
154	int bitnr = to_sensor_dev_attr(attr)->index;
155	struct ad7414_data *data = ad7414_update_device(dev);
156	int value = (data->temp_input >> bitnr) & 1;
157	return sprintf(buf, "%d\n", value);
158}
159
160static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
161static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);
162
163static struct attribute *ad7414_attributes[] = {
164	&sensor_dev_attr_temp1_input.dev_attr.attr,
165	&sensor_dev_attr_temp1_max.dev_attr.attr,
166	&sensor_dev_attr_temp1_min.dev_attr.attr,
167	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
168	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
169	NULL
170};
171
172static const struct attribute_group ad7414_group = {
173	.attrs = ad7414_attributes,
174};
175
176static int ad7414_probe(struct i2c_client *client,
177			const struct i2c_device_id *dev_id)
178{
179	struct ad7414_data *data;
180	int conf;
181	int err = 0;
182
183	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
184				     I2C_FUNC_SMBUS_READ_WORD_DATA))
185		goto exit;
186
187	data = kzalloc(sizeof(struct ad7414_data), GFP_KERNEL);
188	if (!data) {
189		err = -ENOMEM;
190		goto exit;
191	}
192
193	i2c_set_clientdata(client, data);
194	mutex_init(&data->lock);
195
196	dev_info(&client->dev, "chip found\n");
197
198	/* Make sure the chip is powered up. */
199	conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
200	if (conf < 0)
201		dev_warn(&client->dev,
202			 "ad7414_probe unable to read config register.\n");
203	else {
204		conf &= ~(1 << 7);
205		i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
206	}
207
208	/* Register sysfs hooks */
209	err = sysfs_create_group(&client->dev.kobj, &ad7414_group);
210	if (err)
211		goto exit_free;
212
213	data->hwmon_dev = hwmon_device_register(&client->dev);
214	if (IS_ERR(data->hwmon_dev)) {
215		err = PTR_ERR(data->hwmon_dev);
216		goto exit_remove;
217	}
218
219	return 0;
220
221exit_remove:
222	sysfs_remove_group(&client->dev.kobj, &ad7414_group);
223exit_free:
224	kfree(data);
225exit:
226	return err;
227}
228
229static int __devexit ad7414_remove(struct i2c_client *client)
230{
231	struct ad7414_data *data = i2c_get_clientdata(client);
232
233	hwmon_device_unregister(data->hwmon_dev);
234	sysfs_remove_group(&client->dev.kobj, &ad7414_group);
235	kfree(data);
236	return 0;
237}
238
239static const struct i2c_device_id ad7414_id[] = {
240	{ "ad7414", 0 },
241	{}
242};
243
244static struct i2c_driver ad7414_driver = {
245	.driver = {
246		.name	= "ad7414",
247	},
248	.probe	= ad7414_probe,
249	.remove	= __devexit_p(ad7414_remove),
250	.id_table = ad7414_id,
251};
252
253static int __init ad7414_init(void)
254{
255	return i2c_add_driver(&ad7414_driver);
256}
257module_init(ad7414_init);
258
259static void __exit ad7414_exit(void)
260{
261	i2c_del_driver(&ad7414_driver);
262}
263module_exit(ad7414_exit);
264
265MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
266	      "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
267
268MODULE_DESCRIPTION("AD7414 driver");
269MODULE_LICENSE("GPL");