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1 | /* | |
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 | #include <linux/bitops.h> | |
20 | ||
21 | /* | |
22 | * AD7314 temperature masks | |
23 | */ | |
24 | #define AD7314_TEMP_MASK 0x7FE0 | |
25 | #define AD7314_TEMP_SHIFT 5 | |
26 | ||
27 | /* | |
28 | * ADT7301 and ADT7302 temperature masks | |
29 | */ | |
30 | #define ADT7301_TEMP_MASK 0x3FFF | |
31 | ||
32 | enum ad7314_variant { | |
33 | adt7301, | |
34 | adt7302, | |
35 | ad7314, | |
36 | }; | |
37 | ||
38 | struct ad7314_data { | |
39 | struct spi_device *spi_dev; | |
40 | u16 rx ____cacheline_aligned; | |
41 | }; | |
42 | ||
43 | static int ad7314_spi_read(struct ad7314_data *chip) | |
44 | { | |
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 | ||
53 | return be16_to_cpu(chip->rx); | |
54 | } | |
55 | ||
56 | static 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 | ||
64 | ret = ad7314_spi_read(chip); | |
65 | if (ret < 0) | |
66 | return ret; | |
67 | switch (spi_get_device_id(chip->spi_dev)->driver_data) { | |
68 | case ad7314: | |
69 | data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT; | |
70 | data = sign_extend32(data, 9); | |
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 | */ | |
80 | data = ret & ADT7301_TEMP_MASK; | |
81 | data = sign_extend32(data, 13); | |
82 | ||
83 | return sprintf(buf, "%d\n", | |
84 | DIV_ROUND_CLOSEST(data * 3125, 100)); | |
85 | default: | |
86 | return -EINVAL; | |
87 | } | |
88 | } | |
89 | ||
90 | static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, | |
91 | ad7314_show_temperature, NULL, 0); | |
92 | ||
93 | static struct attribute *ad7314_attrs[] = { | |
94 | &sensor_dev_attr_temp1_input.dev_attr.attr, | |
95 | NULL, | |
96 | }; | |
97 | ||
98 | ATTRIBUTE_GROUPS(ad7314); | |
99 | ||
100 | static int ad7314_probe(struct spi_device *spi_dev) | |
101 | { | |
102 | struct ad7314_data *chip; | |
103 | struct device *hwmon_dev; | |
104 | ||
105 | chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL); | |
106 | if (chip == NULL) | |
107 | return -ENOMEM; | |
108 | ||
109 | chip->spi_dev = spi_dev; | |
110 | hwmon_dev = devm_hwmon_device_register_with_groups(&spi_dev->dev, | |
111 | spi_dev->modalias, | |
112 | chip, ad7314_groups); | |
113 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
114 | } | |
115 | ||
116 | static const struct spi_device_id ad7314_id[] = { | |
117 | { "adt7301", adt7301 }, | |
118 | { "adt7302", adt7302 }, | |
119 | { "ad7314", ad7314 }, | |
120 | { } | |
121 | }; | |
122 | MODULE_DEVICE_TABLE(spi, ad7314_id); | |
123 | ||
124 | static struct spi_driver ad7314_driver = { | |
125 | .driver = { | |
126 | .name = "ad7314", | |
127 | }, | |
128 | .probe = ad7314_probe, | |
129 | .id_table = ad7314_id, | |
130 | }; | |
131 | ||
132 | module_spi_driver(ad7314_driver); | |
133 | ||
134 | MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); | |
135 | MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver"); | |
136 | MODULE_LICENSE("GPL v2"); |