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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/*
Jonathan Cameron4f3a6592011-09-29 12:50:04 -040021 * AD7314 temperature masks
22 */
Jonathan Cameron4f3a6592011-09-29 12:50:04 -040023#define AD7314_TEMP_MASK 0x7FE0
Guenter Roeck1137a9a2012-04-22 00:22:00 -040024#define AD7314_TEMP_SHIFT 5
Jonathan Cameron4f3a6592011-09-29 12:50:04 -040025
26/*
27 * ADT7301 and ADT7302 temperature masks
28 */
Jonathan Cameron4f3a6592011-09-29 12:50:04 -040029#define ADT7301_TEMP_MASK 0x3FFF
30
31enum ad7314_variant {
32 adt7301,
33 adt7302,
34 ad7314,
35};
36
37struct ad7314_data {
38 struct spi_device *spi_dev;
39 struct device *hwmon_dev;
40 u16 rx ____cacheline_aligned;
41};
42
Guenter Roeckeae14152012-04-20 11:39:17 -040043static int ad7314_spi_read(struct ad7314_data *chip)
Jonathan Cameron4f3a6592011-09-29 12:50:04 -040044{
45 int ret;
46
47 ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx));
48 if (ret < 0) {
49 dev_err(&chip->spi_dev->dev, "SPI read error\n");
50 return ret;
51 }
52
Guenter Roeckeae14152012-04-20 11:39:17 -040053 return be16_to_cpu(chip->rx);
Jonathan Cameron4f3a6592011-09-29 12:50:04 -040054}
55
56static ssize_t ad7314_show_temperature(struct device *dev,
57 struct device_attribute *attr,
58 char *buf)
59{
60 struct ad7314_data *chip = dev_get_drvdata(dev);
61 s16 data;
62 int ret;
63
Guenter Roeckeae14152012-04-20 11:39:17 -040064 ret = ad7314_spi_read(chip);
Jonathan Cameron4f3a6592011-09-29 12:50:04 -040065 if (ret < 0)
66 return ret;
67 switch (spi_get_device_id(chip->spi_dev)->driver_data) {
68 case ad7314:
Guenter Roeck1137a9a2012-04-22 00:22:00 -040069 data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT;
Jonathan Cameron4f3a6592011-09-29 12:50:04 -040070 data = (data << 6) >> 6;
71
72 return sprintf(buf, "%d\n", 250 * data);
73 case adt7301:
74 case adt7302:
75 /*
76 * Documented as a 13 bit twos complement register
77 * with a sign bit - which is a 14 bit 2's complement
78 * register. 1lsb - 31.25 milli degrees centigrade
79 */
Guenter Roeckeae14152012-04-20 11:39:17 -040080 data = ret & ADT7301_TEMP_MASK;
Jonathan Cameron4f3a6592011-09-29 12:50:04 -040081 data = (data << 2) >> 2;
82
83 return sprintf(buf, "%d\n",
84 DIV_ROUND_CLOSEST(data * 3125, 100));
85 default:
86 return -EINVAL;
87 }
88}
89
90static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
91 ad7314_show_temperature, NULL, 0);
92
93static struct attribute *ad7314_attributes[] = {
94 &sensor_dev_attr_temp1_input.dev_attr.attr,
95 NULL,
96};
97
98static const struct attribute_group ad7314_group = {
99 .attrs = ad7314_attributes,
100};
101
102static int __devinit ad7314_probe(struct spi_device *spi_dev)
103{
104 int ret;
105 struct ad7314_data *chip;
106
107 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
108 if (chip == NULL) {
109 ret = -ENOMEM;
110 goto error_ret;
111 }
112 dev_set_drvdata(&spi_dev->dev, chip);
113
114 ret = sysfs_create_group(&spi_dev->dev.kobj, &ad7314_group);
115 if (ret < 0)
116 goto error_free_chip;
117 chip->hwmon_dev = hwmon_device_register(&spi_dev->dev);
118 if (IS_ERR(chip->hwmon_dev)) {
119 ret = PTR_ERR(chip->hwmon_dev);
120 goto error_remove_group;
121 }
Graeme Smechere16de912012-04-03 19:42:21 -0400122 chip->spi_dev = spi_dev;
Jonathan Cameron4f3a6592011-09-29 12:50:04 -0400123
124 return 0;
125error_remove_group:
126 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group);
127error_free_chip:
128 kfree(chip);
129error_ret:
130 return ret;
131}
132
133static int __devexit ad7314_remove(struct spi_device *spi_dev)
134{
135 struct ad7314_data *chip = dev_get_drvdata(&spi_dev->dev);
136
137 hwmon_device_unregister(chip->hwmon_dev);
138 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group);
139 kfree(chip);
140
141 return 0;
142}
143
144static const struct spi_device_id ad7314_id[] = {
145 { "adt7301", adt7301 },
146 { "adt7302", adt7302 },
147 { "ad7314", ad7314 },
148 { }
149};
150MODULE_DEVICE_TABLE(spi, ad7314_id);
151
152static struct spi_driver ad7314_driver = {
153 .driver = {
154 .name = "ad7314",
Jonathan Cameron4f3a6592011-09-29 12:50:04 -0400155 .owner = THIS_MODULE,
156 },
157 .probe = ad7314_probe,
158 .remove = __devexit_p(ad7314_remove),
159 .id_table = ad7314_id,
160};
161
Axel Lin91efffe2012-01-20 15:53:47 +0800162module_spi_driver(ad7314_driver);
Jonathan Cameron4f3a6592011-09-29 12:50:04 -0400163
164MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
165MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital"
166 " temperature sensor driver");
167MODULE_LICENSE("GPL v2");