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 temp_input_show(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_RO(temp1_input, temp_input, 0);
117
118static ssize_t max_min_show(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 max_min_store(struct device *dev,
127 struct device_attribute *attr, const char *buf,
128 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_RW(temp1_max, max_min, 0);
151static SENSOR_DEVICE_ATTR_RW(temp1_min, max_min, 1);
152
153static ssize_t alarm_show(struct device *dev, struct device_attribute *attr,
154 char *buf)
155{
156 int bitnr = to_sensor_dev_attr(attr)->index;
157 struct ad7414_data *data = ad7414_update_device(dev);
158 int value = (data->temp_input >> bitnr) & 1;
159 return sprintf(buf, "%d\n", value);
160}
161
162static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 3);
163static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 4);
164
165static struct attribute *ad7414_attrs[] = {
166 &sensor_dev_attr_temp1_input.dev_attr.attr,
167 &sensor_dev_attr_temp1_max.dev_attr.attr,
168 &sensor_dev_attr_temp1_min.dev_attr.attr,
169 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
170 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
171 NULL
172};
173
174ATTRIBUTE_GROUPS(ad7414);
175
176static int ad7414_probe(struct i2c_client *client,
177 const struct i2c_device_id *dev_id)
178{
179 struct device *dev = &client->dev;
180 struct ad7414_data *data;
181 struct device *hwmon_dev;
182 int conf;
183
184 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
185 I2C_FUNC_SMBUS_READ_WORD_DATA))
186 return -EOPNOTSUPP;
187
188 data = devm_kzalloc(dev, sizeof(struct ad7414_data), GFP_KERNEL);
189 if (!data)
190 return -ENOMEM;
191
192 data->client = client;
193 mutex_init(&data->lock);
194
195 dev_info(&client->dev, "chip found\n");
196
197 /* Make sure the chip is powered up. */
198 conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
199 if (conf < 0)
200 dev_warn(dev, "ad7414_probe unable to read config register.\n");
201 else {
202 conf &= ~(1 << 7);
203 i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
204 }
205
206 hwmon_dev = devm_hwmon_device_register_with_groups(dev,
207 client->name,
208 data, ad7414_groups);
209 return PTR_ERR_OR_ZERO(hwmon_dev);
210}
211
212static const struct i2c_device_id ad7414_id[] = {
213 { "ad7414", 0 },
214 {}
215};
216MODULE_DEVICE_TABLE(i2c, ad7414_id);
217
218static const struct of_device_id ad7414_of_match[] = {
219 { .compatible = "ad,ad7414" },
220 { },
221};
222MODULE_DEVICE_TABLE(of, ad7414_of_match);
223
224static struct i2c_driver ad7414_driver = {
225 .driver = {
226 .name = "ad7414",
227 .of_match_table = of_match_ptr(ad7414_of_match),
228 },
229 .probe = ad7414_probe,
230 .id_table = ad7414_id,
231};
232
233module_i2c_driver(ad7414_driver);
234
235MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
236 "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
237
238MODULE_DESCRIPTION("AD7414 driver");
239MODULE_LICENSE("GPL");
240