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 #define AD7314_LEADING_ZEROS_MASK BIT(15)
26
27 /*
28 * ADT7301 and ADT7302 temperature masks
29 */
30 #define ADT7301_TEMP_MASK 0x3FFF
31 #define ADT7301_LEADING_ZEROS_MASK (BIT(15) | BIT(14))
32
33 enum ad7314_variant {
34 adt7301,
35 adt7302,
36 ad7314,
37 };
38
39 struct ad7314_data {
40 struct spi_device *spi_dev;
41 u16 rx ____cacheline_aligned;
42 };
43
ad7314_spi_read(struct ad7314_data * chip)44 static int ad7314_spi_read(struct ad7314_data *chip)
45 {
46 int ret;
47
48 ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx));
49 if (ret < 0) {
50 dev_err(&chip->spi_dev->dev, "SPI read error\n");
51 return ret;
52 }
53
54 return be16_to_cpu(chip->rx);
55 }
56
ad7314_temperature_show(struct device * dev,struct device_attribute * attr,char * buf)57 static ssize_t ad7314_temperature_show(struct device *dev,
58 struct device_attribute *attr,
59 char *buf)
60 {
61 struct ad7314_data *chip = dev_get_drvdata(dev);
62 s16 data;
63 int ret;
64
65 ret = ad7314_spi_read(chip);
66 if (ret < 0)
67 return ret;
68 switch (spi_get_device_id(chip->spi_dev)->driver_data) {
69 case ad7314:
70 if (ret & AD7314_LEADING_ZEROS_MASK) {
71 /* Invalid read-out, leading zero part is missing */
72 return -EIO;
73 }
74 data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT;
75 data = sign_extend32(data, 9);
76
77 return sprintf(buf, "%d\n", 250 * data);
78 case adt7301:
79 case adt7302:
80 if (ret & ADT7301_LEADING_ZEROS_MASK) {
81 /* Invalid read-out, leading zero part is missing */
82 return -EIO;
83 }
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 = ret & ADT7301_TEMP_MASK;
90 data = sign_extend32(data, 13);
91
92 return sprintf(buf, "%d\n",
93 DIV_ROUND_CLOSEST(data * 3125, 100));
94 default:
95 return -EINVAL;
96 }
97 }
98
99 static SENSOR_DEVICE_ATTR_RO(temp1_input, ad7314_temperature, 0);
100
101 static struct attribute *ad7314_attrs[] = {
102 &sensor_dev_attr_temp1_input.dev_attr.attr,
103 NULL,
104 };
105
106 ATTRIBUTE_GROUPS(ad7314);
107
ad7314_probe(struct spi_device * spi_dev)108 static int ad7314_probe(struct spi_device *spi_dev)
109 {
110 struct ad7314_data *chip;
111 struct device *hwmon_dev;
112
113 chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL);
114 if (chip == NULL)
115 return -ENOMEM;
116
117 chip->spi_dev = spi_dev;
118 hwmon_dev = devm_hwmon_device_register_with_groups(&spi_dev->dev,
119 spi_dev->modalias,
120 chip, ad7314_groups);
121 return PTR_ERR_OR_ZERO(hwmon_dev);
122 }
123
124 static const struct spi_device_id ad7314_id[] = {
125 { "adt7301", adt7301 },
126 { "adt7302", adt7302 },
127 { "ad7314", ad7314 },
128 { }
129 };
130 MODULE_DEVICE_TABLE(spi, ad7314_id);
131
132 static struct spi_driver ad7314_driver = {
133 .driver = {
134 .name = "ad7314",
135 },
136 .probe = ad7314_probe,
137 .id_table = ad7314_id,
138 };
139
140 module_spi_driver(ad7314_driver);
141
142 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
143 MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver");
144 MODULE_LICENSE("GPL v2");
145