blob: 5d760f3d21c2d61ee85227ab7107bf4c38e011f9 [file] [log] [blame]
Jonathan Cameron4f3a6592011-09-29 12:50:04 -04001/*
2 * AD7314 digital temperature sensor driver for AD7314, ADT7301 and ADT7302
3 *
4 * Copyright 2010 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2 or later.
7 *
8 * Conversion to hwmon from IIO done by Jonathan Cameron <jic23@cam.ac.uk>
9 */
10#include <linux/device.h>
11#include <linux/kernel.h>
12#include <linux/slab.h>
13#include <linux/sysfs.h>
14#include <linux/spi/spi.h>
15#include <linux/module.h>
16#include <linux/err.h>
17#include <linux/hwmon.h>
18#include <linux/hwmon-sysfs.h>
19
20/*
21 * AD7314 power mode
22 */
23#define AD7314_PD 0x2000
24
25/*
26 * AD7314 temperature masks
27 */
28#define AD7314_TEMP_SIGN 0x200
29#define AD7314_TEMP_MASK 0x7FE0
30#define AD7314_TEMP_OFFSET 5
31
32/*
33 * ADT7301 and ADT7302 temperature masks
34 */
35#define ADT7301_TEMP_SIGN 0x2000
36#define ADT7301_TEMP_MASK 0x3FFF
37
38enum ad7314_variant {
39 adt7301,
40 adt7302,
41 ad7314,
42};
43
44struct ad7314_data {
45 struct spi_device *spi_dev;
46 struct device *hwmon_dev;
47 u16 rx ____cacheline_aligned;
48};
49
50static int ad7314_spi_read(struct ad7314_data *chip, s16 *data)
51{
52 int ret;
53
54 ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx));
55 if (ret < 0) {
56 dev_err(&chip->spi_dev->dev, "SPI read error\n");
57 return ret;
58 }
59
60 *data = be16_to_cpu(chip->rx);
61
62 return ret;
63}
64
65static ssize_t ad7314_show_temperature(struct device *dev,
66 struct device_attribute *attr,
67 char *buf)
68{
69 struct ad7314_data *chip = dev_get_drvdata(dev);
70 s16 data;
71 int ret;
72
73 ret = ad7314_spi_read(chip, &data);
74 if (ret < 0)
75 return ret;
76 switch (spi_get_device_id(chip->spi_dev)->driver_data) {
77 case ad7314:
78 data = (data & AD7314_TEMP_MASK) >> AD7314_TEMP_OFFSET;
79 data = (data << 6) >> 6;
80
81 return sprintf(buf, "%d\n", 250 * data);
82 case adt7301:
83 case adt7302:
84 /*
85 * Documented as a 13 bit twos complement register
86 * with a sign bit - which is a 14 bit 2's complement
87 * register. 1lsb - 31.25 milli degrees centigrade
88 */
89 data &= ADT7301_TEMP_MASK;
90 data = (data << 2) >> 2;
91
92 return sprintf(buf, "%d\n",
93 DIV_ROUND_CLOSEST(data * 3125, 100));
94 default:
95 return -EINVAL;
96 }
97}
98
99static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
100 ad7314_show_temperature, NULL, 0);
101
102static struct attribute *ad7314_attributes[] = {
103 &sensor_dev_attr_temp1_input.dev_attr.attr,
104 NULL,
105};
106
107static const struct attribute_group ad7314_group = {
108 .attrs = ad7314_attributes,
109};
110
111static int __devinit ad7314_probe(struct spi_device *spi_dev)
112{
113 int ret;
114 struct ad7314_data *chip;
115
116 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
117 if (chip == NULL) {
118 ret = -ENOMEM;
119 goto error_ret;
120 }
121 dev_set_drvdata(&spi_dev->dev, chip);
122
123 ret = sysfs_create_group(&spi_dev->dev.kobj, &ad7314_group);
124 if (ret < 0)
125 goto error_free_chip;
126 chip->hwmon_dev = hwmon_device_register(&spi_dev->dev);
127 if (IS_ERR(chip->hwmon_dev)) {
128 ret = PTR_ERR(chip->hwmon_dev);
129 goto error_remove_group;
130 }
131
132 return 0;
133error_remove_group:
134 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group);
135error_free_chip:
136 kfree(chip);
137error_ret:
138 return ret;
139}
140
141static int __devexit ad7314_remove(struct spi_device *spi_dev)
142{
143 struct ad7314_data *chip = dev_get_drvdata(&spi_dev->dev);
144
145 hwmon_device_unregister(chip->hwmon_dev);
146 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group);
147 kfree(chip);
148
149 return 0;
150}
151
152static const struct spi_device_id ad7314_id[] = {
153 { "adt7301", adt7301 },
154 { "adt7302", adt7302 },
155 { "ad7314", ad7314 },
156 { }
157};
158MODULE_DEVICE_TABLE(spi, ad7314_id);
159
160static struct spi_driver ad7314_driver = {
161 .driver = {
162 .name = "ad7314",
Jonathan Cameron4f3a6592011-09-29 12:50:04 -0400163 .owner = THIS_MODULE,
164 },
165 .probe = ad7314_probe,
166 .remove = __devexit_p(ad7314_remove),
167 .id_table = ad7314_id,
168};
169
170static __init int ad7314_init(void)
171{
172 return spi_register_driver(&ad7314_driver);
173}
174module_init(ad7314_init);
175
176static __exit void ad7314_exit(void)
177{
178 spi_unregister_driver(&ad7314_driver);
179}
180module_exit(ad7314_exit);
181
182MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
183MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital"
184 " temperature sensor driver");
185MODULE_LICENSE("GPL v2");