1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * AD7314 digital temperature sensor driver for AD7314, ADT7301 and ADT7302
4 *
5 * Copyright 2010 Analog Devices Inc.
6 *
7 * Conversion to hwmon from IIO done by Jonathan Cameron <jic23@cam.ac.uk>
8 */
9 #include <linux/device.h>
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/sysfs.h>
13 #include <linux/spi/spi.h>
14 #include <linux/module.h>
15 #include <linux/err.h>
16 #include <linux/hwmon.h>
17 #include <linux/hwmon-sysfs.h>
18 #include <linux/bitops.h>
19
20 /*
21 * AD7314 temperature masks
22 */
23 #define AD7314_TEMP_MASK 0x7FE0
24 #define AD7314_TEMP_SHIFT 5
25
26 /*
27 * ADT7301 and ADT7302 temperature masks
28 */
29 #define ADT7301_TEMP_MASK 0x3FFF
30
31 enum ad7314_variant {
32 adt7301,
33 adt7302,
34 ad7314,
35 };
36
37 struct ad7314_data {
38 struct spi_device *spi_dev;
39 u16 rx ____cacheline_aligned;
40 };
41
ad7314_spi_read(struct ad7314_data * chip)42 static int ad7314_spi_read(struct ad7314_data *chip)
43 {
44 int ret;
45
46 ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx));
47 if (ret < 0) {
48 dev_err(&chip->spi_dev->dev, "SPI read error\n");
49 return ret;
50 }
51
52 return be16_to_cpu(chip->rx);
53 }
54
ad7314_temperature_show(struct device * dev,struct device_attribute * attr,char * buf)55 static ssize_t ad7314_temperature_show(struct device *dev,
56 struct device_attribute *attr,
57 char *buf)
58 {
59 struct ad7314_data *chip = dev_get_drvdata(dev);
60 s16 data;
61 int ret;
62
63 ret = ad7314_spi_read(chip);
64 if (ret < 0)
65 return ret;
66 switch (spi_get_device_id(chip->spi_dev)->driver_data) {
67 case ad7314:
68 data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT;
69 data = sign_extend32(data, 9);
70
71 return sprintf(buf, "%d\n", 250 * data);
72 case adt7301:
73 case adt7302:
74 /*
75 * Documented as a 13 bit twos complement register
76 * with a sign bit - which is a 14 bit 2's complement
77 * register. 1lsb - 31.25 milli degrees centigrade
78 */
79 data = ret & ADT7301_TEMP_MASK;
80 data = sign_extend32(data, 13);
81
82 return sprintf(buf, "%d\n",
83 DIV_ROUND_CLOSEST(data * 3125, 100));
84 default:
85 return -EINVAL;
86 }
87 }
88
89 static SENSOR_DEVICE_ATTR_RO(temp1_input, ad7314_temperature, 0);
90
91 static struct attribute *ad7314_attrs[] = {
92 &sensor_dev_attr_temp1_input.dev_attr.attr,
93 NULL,
94 };
95
96 ATTRIBUTE_GROUPS(ad7314);
97
ad7314_probe(struct spi_device * spi_dev)98 static int ad7314_probe(struct spi_device *spi_dev)
99 {
100 struct ad7314_data *chip;
101 struct device *hwmon_dev;
102
103 chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL);
104 if (chip == NULL)
105 return -ENOMEM;
106
107 chip->spi_dev = spi_dev;
108 hwmon_dev = devm_hwmon_device_register_with_groups(&spi_dev->dev,
109 spi_dev->modalias,
110 chip, ad7314_groups);
111 return PTR_ERR_OR_ZERO(hwmon_dev);
112 }
113
114 static const struct spi_device_id ad7314_id[] = {
115 { "adt7301", adt7301 },
116 { "adt7302", adt7302 },
117 { "ad7314", ad7314 },
118 { }
119 };
120 MODULE_DEVICE_TABLE(spi, ad7314_id);
121
122 static struct spi_driver ad7314_driver = {
123 .driver = {
124 .name = "ad7314",
125 },
126 .probe = ad7314_probe,
127 .id_table = ad7314_id,
128 };
129
130 module_spi_driver(ad7314_driver);
131
132 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
133 MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver");
134 MODULE_LICENSE("GPL v2");
135