Commit | Line | Data |
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04e1e70a TB |
1 | /* |
2 | * max31722 - hwmon driver for Maxim Integrated MAX31722/MAX31723 SPI | |
3 | * digital thermometer and thermostats. | |
4 | * | |
5 | * Copyright (c) 2016, Intel Corporation. | |
6 | * | |
7 | * This file is subject to the terms and conditions of version 2 of | |
8 | * the GNU General Public License. See the file COPYING in the main | |
9 | * directory of this archive for more details. | |
10 | */ | |
11 | ||
12 | #include <linux/acpi.h> | |
13 | #include <linux/hwmon.h> | |
14 | #include <linux/hwmon-sysfs.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/spi/spi.h> | |
18 | ||
19 | #define MAX31722_REG_CFG 0x00 | |
20 | #define MAX31722_REG_TEMP_LSB 0x01 | |
21 | ||
22 | #define MAX31722_MODE_CONTINUOUS 0x00 | |
23 | #define MAX31722_MODE_STANDBY 0x01 | |
24 | #define MAX31722_MODE_MASK 0xFE | |
25 | #define MAX31722_RESOLUTION_12BIT 0x06 | |
26 | #define MAX31722_WRITE_MASK 0x80 | |
27 | ||
28 | struct max31722_data { | |
29 | struct device *hwmon_dev; | |
30 | struct spi_device *spi_device; | |
31 | u8 mode; | |
32 | }; | |
33 | ||
34 | static int max31722_set_mode(struct max31722_data *data, u8 mode) | |
35 | { | |
36 | int ret; | |
37 | struct spi_device *spi = data->spi_device; | |
38 | u8 buf[2] = { | |
39 | MAX31722_REG_CFG | MAX31722_WRITE_MASK, | |
40 | (data->mode & MAX31722_MODE_MASK) | mode | |
41 | }; | |
42 | ||
43 | ret = spi_write(spi, &buf, sizeof(buf)); | |
44 | if (ret < 0) { | |
45 | dev_err(&spi->dev, "failed to set sensor mode.\n"); | |
46 | return ret; | |
47 | } | |
48 | data->mode = (data->mode & MAX31722_MODE_MASK) | mode; | |
49 | ||
50 | return 0; | |
51 | } | |
52 | ||
53 | static ssize_t max31722_show_temp(struct device *dev, | |
54 | struct device_attribute *attr, | |
55 | char *buf) | |
56 | { | |
57 | ssize_t ret; | |
58 | struct max31722_data *data = dev_get_drvdata(dev); | |
59 | ||
60 | ret = spi_w8r16(data->spi_device, MAX31722_REG_TEMP_LSB); | |
61 | if (ret < 0) | |
62 | return ret; | |
63 | /* Keep 12 bits and multiply by the scale of 62.5 millidegrees/bit. */ | |
64 | return sprintf(buf, "%d\n", (s16)le16_to_cpu(ret) * 125 / 32); | |
65 | } | |
66 | ||
67 | static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, | |
68 | max31722_show_temp, NULL, 0); | |
69 | ||
70 | static struct attribute *max31722_attrs[] = { | |
71 | &sensor_dev_attr_temp1_input.dev_attr.attr, | |
72 | NULL, | |
73 | }; | |
74 | ||
75 | ATTRIBUTE_GROUPS(max31722); | |
76 | ||
77 | static int max31722_probe(struct spi_device *spi) | |
78 | { | |
79 | int ret; | |
80 | struct max31722_data *data; | |
81 | ||
82 | data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL); | |
83 | if (!data) | |
84 | return -ENOMEM; | |
85 | ||
86 | spi_set_drvdata(spi, data); | |
87 | data->spi_device = spi; | |
88 | /* | |
89 | * Set SD bit to 0 so we can have continuous measurements. | |
90 | * Set resolution to 12 bits for maximum precision. | |
91 | */ | |
92 | data->mode = MAX31722_MODE_CONTINUOUS | MAX31722_RESOLUTION_12BIT; | |
93 | ret = max31722_set_mode(data, MAX31722_MODE_CONTINUOUS); | |
94 | if (ret < 0) | |
95 | return ret; | |
96 | ||
97 | data->hwmon_dev = hwmon_device_register_with_groups(&spi->dev, | |
98 | spi->modalias, | |
99 | data, | |
100 | max31722_groups); | |
101 | if (IS_ERR(data->hwmon_dev)) { | |
102 | max31722_set_mode(data, MAX31722_MODE_STANDBY); | |
103 | return PTR_ERR(data->hwmon_dev); | |
104 | } | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | static int max31722_remove(struct spi_device *spi) | |
110 | { | |
111 | struct max31722_data *data = spi_get_drvdata(spi); | |
112 | ||
113 | hwmon_device_unregister(data->hwmon_dev); | |
114 | ||
115 | return max31722_set_mode(data, MAX31722_MODE_STANDBY); | |
116 | } | |
117 | ||
118 | static int __maybe_unused max31722_suspend(struct device *dev) | |
119 | { | |
120 | struct spi_device *spi_device = to_spi_device(dev); | |
121 | struct max31722_data *data = spi_get_drvdata(spi_device); | |
122 | ||
123 | return max31722_set_mode(data, MAX31722_MODE_STANDBY); | |
124 | } | |
125 | ||
126 | static int __maybe_unused max31722_resume(struct device *dev) | |
127 | { | |
128 | struct spi_device *spi_device = to_spi_device(dev); | |
129 | struct max31722_data *data = spi_get_drvdata(spi_device); | |
130 | ||
131 | return max31722_set_mode(data, MAX31722_MODE_CONTINUOUS); | |
132 | } | |
133 | ||
134 | static SIMPLE_DEV_PM_OPS(max31722_pm_ops, max31722_suspend, max31722_resume); | |
135 | ||
136 | static const struct spi_device_id max31722_spi_id[] = { | |
137 | {"max31722", 0}, | |
138 | {"max31723", 0}, | |
139 | {} | |
140 | }; | |
141 | ||
142 | static const struct acpi_device_id __maybe_unused max31722_acpi_id[] = { | |
143 | {"MAX31722", 0}, | |
144 | {"MAX31723", 0}, | |
145 | {} | |
146 | }; | |
147 | ||
148 | MODULE_DEVICE_TABLE(spi, max31722_spi_id); | |
149 | ||
150 | static struct spi_driver max31722_driver = { | |
151 | .driver = { | |
152 | .name = "max31722", | |
153 | .pm = &max31722_pm_ops, | |
154 | .acpi_match_table = ACPI_PTR(max31722_acpi_id), | |
155 | }, | |
156 | .probe = max31722_probe, | |
157 | .remove = max31722_remove, | |
158 | .id_table = max31722_spi_id, | |
159 | }; | |
160 | ||
161 | module_spi_driver(max31722_driver); | |
162 | ||
163 | MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>"); | |
164 | MODULE_DESCRIPTION("max31722 sensor driver"); | |
165 | MODULE_LICENSE("GPL v2"); |