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 i2c_client	*client;
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	/*
54	 * use integer division instead of equivalent right shift to
55	 * guarantee arithmetic shift and preserve the sign
56	 */
57	return ((int)reg / 64) * 250;
58}
59
60static inline int ad7414_read(struct i2c_client *client, u8 reg)
61{
62	if (reg == AD7414_REG_TEMP)
63		return i2c_smbus_read_word_swapped(client, reg);
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 ad7414_data *data = dev_get_drvdata(dev);
76	struct i2c_client *client = data->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 ad7414_data *data = dev_get_drvdata(dev);
131	struct i2c_client *client = data->client;
132	int index = to_sensor_dev_attr(attr)->index;
133	u8 reg = AD7414_REG_LIMIT[index];
134	long temp;
135	int ret = kstrtol(buf, 10, &temp);
136
137	if (ret < 0)
138		return ret;
139
140	temp = clamp_val(temp, -40000, 85000);
141	temp = (temp + (temp < 0 ? -500 : 500)) / 1000;
142
143	mutex_lock(&data->lock);
144	data->temps[index] = temp;
145	ad7414_write(client, reg, temp);
146	mutex_unlock(&data->lock);
147	return count;
148}
149
150static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
151			  show_max_min, set_max_min, 0);
152static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
153			  show_max_min, set_max_min, 1);
154
155static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
156			  char *buf)
157{
158	int bitnr = to_sensor_dev_attr(attr)->index;
159	struct ad7414_data *data = ad7414_update_device(dev);
160	int value = (data->temp_input >> bitnr) & 1;
161	return sprintf(buf, "%d\n", value);
162}
163
164static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
165static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);
166
167static struct attribute *ad7414_attrs[] = {
168	&sensor_dev_attr_temp1_input.dev_attr.attr,
169	&sensor_dev_attr_temp1_max.dev_attr.attr,
170	&sensor_dev_attr_temp1_min.dev_attr.attr,
171	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
172	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
173	NULL
174};
175
176ATTRIBUTE_GROUPS(ad7414);
177
178static int ad7414_probe(struct i2c_client *client,
179			const struct i2c_device_id *dev_id)
180{
181	struct device *dev = &client->dev;
182	struct ad7414_data *data;
183	struct device *hwmon_dev;
184	int conf;
185
186	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
187				     I2C_FUNC_SMBUS_READ_WORD_DATA))
188		return -EOPNOTSUPP;
189
190	data = devm_kzalloc(dev, sizeof(struct ad7414_data), GFP_KERNEL);
191	if (!data)
192		return -ENOMEM;
193
194	data->client = client;
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(dev, "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	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
209							   client->name,
210							   data, ad7414_groups);
211	return PTR_ERR_OR_ZERO(hwmon_dev);
212}
213
214static const struct i2c_device_id ad7414_id[] = {
215	{ "ad7414", 0 },
216	{}
217};
218MODULE_DEVICE_TABLE(i2c, ad7414_id);
219
220static struct i2c_driver ad7414_driver = {
221	.driver = {
222		.name	= "ad7414",
223	},
224	.probe	= ad7414_probe,
225	.id_table = ad7414_id,
226};
227
228module_i2c_driver(ad7414_driver);
229
230MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
231	      "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
232
233MODULE_DESCRIPTION("AD7414 driver");
234MODULE_LICENSE("GPL");
235