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		return i2c_smbus_read_word_swapped(client, reg);
63	else
64		return i2c_smbus_read_byte_data(client, reg);
65}
66
67static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value)
68{
69	return i2c_smbus_write_byte_data(client, reg, value);
70}
71
72static struct ad7414_data *ad7414_update_device(struct device *dev)
73{
74	struct i2c_client *client = to_i2c_client(dev);
75	struct ad7414_data *data = i2c_get_clientdata(client);
76
77	mutex_lock(&data->lock);
78
79	if (time_after(jiffies, data->next_update) || !data->valid) {
80		int value, i;
81
82		dev_dbg(&client->dev, "starting ad7414 update\n");
83
84		value = ad7414_read(client, AD7414_REG_TEMP);
85		if (value < 0)
86			dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n",
87				value);
88		else
89			data->temp_input = value;
90
91		for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) {
92			value = ad7414_read(client, AD7414_REG_LIMIT[i]);
93			if (value < 0)
94				dev_dbg(&client->dev, "AD7414 reg %d err %d\n",
95					AD7414_REG_LIMIT[i], value);
96			else
97				data->temps[i] = value;
98		}
99
100		data->next_update = jiffies + HZ + HZ / 2;
101		data->valid = 1;
102	}
103
104	mutex_unlock(&data->lock);
105
106	return data;
107}
108
109static ssize_t show_temp_input(struct device *dev,
110			       struct device_attribute *attr, char *buf)
111{
112	struct ad7414_data *data = ad7414_update_device(dev);
113	return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input));
114}
115static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
116
117static ssize_t show_max_min(struct device *dev, struct device_attribute *attr,
118			  char *buf)
119{
120	int index = to_sensor_dev_attr(attr)->index;
121	struct ad7414_data *data = ad7414_update_device(dev);
122	return sprintf(buf, "%d\n", data->temps[index] * 1000);
123}
124
125static ssize_t set_max_min(struct device *dev,
126			   struct device_attribute *attr,
127			   const char *buf, size_t count)
128{
129	struct i2c_client *client = to_i2c_client(dev);
130	struct ad7414_data *data = i2c_get_clientdata(client);
131	int index = to_sensor_dev_attr(attr)->index;
132	u8 reg = AD7414_REG_LIMIT[index];
133	long temp = simple_strtol(buf, NULL, 10);
134
135	temp = SENSORS_LIMIT(temp, -40000, 85000);
136	temp = (temp + (temp < 0 ? -500 : 500)) / 1000;
137
138	mutex_lock(&data->lock);
139	data->temps[index] = temp;
140	ad7414_write(client, reg, temp);
141	mutex_unlock(&data->lock);
142	return count;
143}
144
145static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
146			  show_max_min, set_max_min, 0);
147static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
148			  show_max_min, set_max_min, 1);
149
150static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
151			  char *buf)
152{
153	int bitnr = to_sensor_dev_attr(attr)->index;
154	struct ad7414_data *data = ad7414_update_device(dev);
155	int value = (data->temp_input >> bitnr) & 1;
156	return sprintf(buf, "%d\n", value);
157}
158
159static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
160static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);
161
162static struct attribute *ad7414_attributes[] = {
163	&sensor_dev_attr_temp1_input.dev_attr.attr,
164	&sensor_dev_attr_temp1_max.dev_attr.attr,
165	&sensor_dev_attr_temp1_min.dev_attr.attr,
166	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
167	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
168	NULL
169};
170
171static const struct attribute_group ad7414_group = {
172	.attrs = ad7414_attributes,
173};
174
175static int ad7414_probe(struct i2c_client *client,
176			const struct i2c_device_id *dev_id)
177{
178	struct ad7414_data *data;
179	int conf;
180	int err;
181
182	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
183				     I2C_FUNC_SMBUS_READ_WORD_DATA)) {
184		err = -EOPNOTSUPP;
185		goto exit;
186	}
187
188	data = kzalloc(sizeof(struct ad7414_data), GFP_KERNEL);
189	if (!data) {
190		err = -ENOMEM;
191		goto exit;
192	}
193
194	i2c_set_clientdata(client, data);
195	mutex_init(&data->lock);
196
197	dev_info(&client->dev, "chip found\n");
198
199	/* Make sure the chip is powered up. */
200	conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
201	if (conf < 0)
202		dev_warn(&client->dev,
203			 "ad7414_probe unable to read config register.\n");
204	else {
205		conf &= ~(1 << 7);
206		i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
207	}
208
209	/* Register sysfs hooks */
210	err = sysfs_create_group(&client->dev.kobj, &ad7414_group);
211	if (err)
212		goto exit_free;
213
214	data->hwmon_dev = hwmon_device_register(&client->dev);
215	if (IS_ERR(data->hwmon_dev)) {
216		err = PTR_ERR(data->hwmon_dev);
217		goto exit_remove;
218	}
219
220	return 0;
221
222exit_remove:
223	sysfs_remove_group(&client->dev.kobj, &ad7414_group);
224exit_free:
225	kfree(data);
226exit:
227	return err;
228}
229
230static int __devexit ad7414_remove(struct i2c_client *client)
231{
232	struct ad7414_data *data = i2c_get_clientdata(client);
233
234	hwmon_device_unregister(data->hwmon_dev);
235	sysfs_remove_group(&client->dev.kobj, &ad7414_group);
236	kfree(data);
237	return 0;
238}
239
240static const struct i2c_device_id ad7414_id[] = {
241	{ "ad7414", 0 },
242	{}
243};
244MODULE_DEVICE_TABLE(i2c, ad7414_id);
245
246static struct i2c_driver ad7414_driver = {
247	.driver = {
248		.name	= "ad7414",
249	},
250	.probe	= ad7414_probe,
251	.remove	= __devexit_p(ad7414_remove),
252	.id_table = ad7414_id,
253};
254
255static int __init ad7414_init(void)
256{
257	return i2c_add_driver(&ad7414_driver);
258}
259module_init(ad7414_init);
260
261static void __exit ad7414_exit(void)
262{
263	i2c_del_driver(&ad7414_driver);
264}
265module_exit(ad7414_exit);
266
267MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
268	      "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
269
270MODULE_DESCRIPTION("AD7414 driver");
271MODULE_LICENSE("GPL");
272