tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * max31722 - hwmon driver for Maxim Integrated MAX31722/MAX31723 SPI
4 * digital thermometer and thermostats.
5 *
6 * Copyright (c) 2016, Intel Corporation.
7 */
8
9#include <linux/acpi.h>
10#include <linux/hwmon.h>
11#include <linux/hwmon-sysfs.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/spi/spi.h>
15
16#define MAX31722_REG_CFG 0x00
17#define MAX31722_REG_TEMP_LSB 0x01
18
19#define MAX31722_MODE_CONTINUOUS 0x00
20#define MAX31722_MODE_STANDBY 0x01
21#define MAX31722_MODE_MASK 0xFE
22#define MAX31722_RESOLUTION_12BIT 0x06
23#define MAX31722_WRITE_MASK 0x80
24
25struct max31722_data {
26 struct device *hwmon_dev;
27 struct spi_device *spi_device;
28 u8 mode;
29};
30
31static int max31722_set_mode(struct max31722_data *data, u8 mode)
32{
33 int ret;
34 struct spi_device *spi = data->spi_device;
35 u8 buf[2] = {
36 MAX31722_REG_CFG | MAX31722_WRITE_MASK,
37 (data->mode & MAX31722_MODE_MASK) | mode
38 };
39
40 ret = spi_write(spi, &buf, sizeof(buf));
41 if (ret < 0) {
42 dev_err(&spi->dev, "failed to set sensor mode.\n");
43 return ret;
44 }
45 data->mode = (data->mode & MAX31722_MODE_MASK) | mode;
46
47 return 0;
48}
49
50static ssize_t max31722_temp_show(struct device *dev,
51 struct device_attribute *attr, char *buf)
52{
53 ssize_t ret;
54 struct max31722_data *data = dev_get_drvdata(dev);
55
56 ret = spi_w8r16(data->spi_device, MAX31722_REG_TEMP_LSB);
57 if (ret < 0)
58 return ret;
59 /* Keep 12 bits and multiply by the scale of 62.5 millidegrees/bit. */
60 return sprintf(buf, "%d\n", (s16)le16_to_cpu(ret) * 125 / 32);
61}
62
63static SENSOR_DEVICE_ATTR_RO(temp1_input, max31722_temp, 0);
64
65static struct attribute *max31722_attrs[] = {
66 &sensor_dev_attr_temp1_input.dev_attr.attr,
67 NULL,
68};
69
70ATTRIBUTE_GROUPS(max31722);
71
72static int max31722_probe(struct spi_device *spi)
73{
74 int ret;
75 struct max31722_data *data;
76
77 data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
78 if (!data)
79 return -ENOMEM;
80
81 spi_set_drvdata(spi, data);
82 data->spi_device = spi;
83 /*
84 * Set SD bit to 0 so we can have continuous measurements.
85 * Set resolution to 12 bits for maximum precision.
86 */
87 data->mode = MAX31722_MODE_CONTINUOUS | MAX31722_RESOLUTION_12BIT;
88 ret = max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);
89 if (ret < 0)
90 return ret;
91
92 data->hwmon_dev = hwmon_device_register_with_groups(&spi->dev,
93 spi->modalias,
94 data,
95 max31722_groups);
96 if (IS_ERR(data->hwmon_dev)) {
97 max31722_set_mode(data, MAX31722_MODE_STANDBY);
98 return PTR_ERR(data->hwmon_dev);
99 }
100
101 return 0;
102}
103
104static int max31722_remove(struct spi_device *spi)
105{
106 struct max31722_data *data = spi_get_drvdata(spi);
107
108 hwmon_device_unregister(data->hwmon_dev);
109
110 return max31722_set_mode(data, MAX31722_MODE_STANDBY);
111}
112
113static int __maybe_unused max31722_suspend(struct device *dev)
114{
115 struct spi_device *spi_device = to_spi_device(dev);
116 struct max31722_data *data = spi_get_drvdata(spi_device);
117
118 return max31722_set_mode(data, MAX31722_MODE_STANDBY);
119}
120
121static int __maybe_unused max31722_resume(struct device *dev)
122{
123 struct spi_device *spi_device = to_spi_device(dev);
124 struct max31722_data *data = spi_get_drvdata(spi_device);
125
126 return max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);
127}
128
129static SIMPLE_DEV_PM_OPS(max31722_pm_ops, max31722_suspend, max31722_resume);
130
131static const struct spi_device_id max31722_spi_id[] = {
132 {"max31722", 0},
133 {"max31723", 0},
134 {}
135};
136
137static const struct acpi_device_id __maybe_unused max31722_acpi_id[] = {
138 {"MAX31722", 0},
139 {"MAX31723", 0},
140 {}
141};
142
143MODULE_DEVICE_TABLE(spi, max31722_spi_id);
144
145static struct spi_driver max31722_driver = {
146 .driver = {
147 .name = "max31722",
148 .pm = &max31722_pm_ops,
149 .acpi_match_table = ACPI_PTR(max31722_acpi_id),
150 },
151 .probe = max31722_probe,
152 .remove = max31722_remove,
153 .id_table = max31722_spi_id,
154};
155
156module_spi_driver(max31722_driver);
157
158MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
159MODULE_DESCRIPTION("max31722 sensor driver");
160MODULE_LICENSE("GPL v2");