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36edc939 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
04e1e70a TB |
2 | /* |
3 | * max31722 - hwmon driver for Maxim Integrated MAX31722/MAX31723 SPI | |
4 | * digital thermometer and thermostats. | |
5 | * | |
6 | * Copyright (c) 2016, Intel Corporation. | |
04e1e70a TB |
7 | */ |
8 | ||
04e1e70a TB |
9 | #include <linux/hwmon.h> |
10 | #include <linux/hwmon-sysfs.h> | |
11 | #include <linux/kernel.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/spi/spi.h> | |
14 | ||
15 | #define MAX31722_REG_CFG 0x00 | |
16 | #define MAX31722_REG_TEMP_LSB 0x01 | |
17 | ||
18 | #define MAX31722_MODE_CONTINUOUS 0x00 | |
19 | #define MAX31722_MODE_STANDBY 0x01 | |
20 | #define MAX31722_MODE_MASK 0xFE | |
21 | #define MAX31722_RESOLUTION_12BIT 0x06 | |
22 | #define MAX31722_WRITE_MASK 0x80 | |
23 | ||
24 | struct max31722_data { | |
25 | struct device *hwmon_dev; | |
26 | struct spi_device *spi_device; | |
27 | u8 mode; | |
28 | }; | |
29 | ||
30 | static int max31722_set_mode(struct max31722_data *data, u8 mode) | |
31 | { | |
32 | int ret; | |
33 | struct spi_device *spi = data->spi_device; | |
34 | u8 buf[2] = { | |
35 | MAX31722_REG_CFG | MAX31722_WRITE_MASK, | |
36 | (data->mode & MAX31722_MODE_MASK) | mode | |
37 | }; | |
38 | ||
39 | ret = spi_write(spi, &buf, sizeof(buf)); | |
40 | if (ret < 0) { | |
41 | dev_err(&spi->dev, "failed to set sensor mode.\n"); | |
42 | return ret; | |
43 | } | |
44 | data->mode = (data->mode & MAX31722_MODE_MASK) | mode; | |
45 | ||
46 | return 0; | |
47 | } | |
48 | ||
845ee709 GR |
49 | static ssize_t max31722_temp_show(struct device *dev, |
50 | struct device_attribute *attr, char *buf) | |
04e1e70a TB |
51 | { |
52 | ssize_t ret; | |
53 | struct max31722_data *data = dev_get_drvdata(dev); | |
54 | ||
55 | ret = spi_w8r16(data->spi_device, MAX31722_REG_TEMP_LSB); | |
56 | if (ret < 0) | |
57 | return ret; | |
58 | /* Keep 12 bits and multiply by the scale of 62.5 millidegrees/bit. */ | |
59 | return sprintf(buf, "%d\n", (s16)le16_to_cpu(ret) * 125 / 32); | |
60 | } | |
61 | ||
845ee709 | 62 | static SENSOR_DEVICE_ATTR_RO(temp1_input, max31722_temp, 0); |
04e1e70a TB |
63 | |
64 | static struct attribute *max31722_attrs[] = { | |
65 | &sensor_dev_attr_temp1_input.dev_attr.attr, | |
66 | NULL, | |
67 | }; | |
68 | ||
69 | ATTRIBUTE_GROUPS(max31722); | |
70 | ||
71 | static int max31722_probe(struct spi_device *spi) | |
72 | { | |
73 | int ret; | |
74 | struct max31722_data *data; | |
75 | ||
76 | data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL); | |
77 | if (!data) | |
78 | return -ENOMEM; | |
79 | ||
80 | spi_set_drvdata(spi, data); | |
81 | data->spi_device = spi; | |
82 | /* | |
83 | * Set SD bit to 0 so we can have continuous measurements. | |
84 | * Set resolution to 12 bits for maximum precision. | |
85 | */ | |
86 | data->mode = MAX31722_MODE_CONTINUOUS | MAX31722_RESOLUTION_12BIT; | |
87 | ret = max31722_set_mode(data, MAX31722_MODE_CONTINUOUS); | |
88 | if (ret < 0) | |
89 | return ret; | |
90 | ||
91 | data->hwmon_dev = hwmon_device_register_with_groups(&spi->dev, | |
92 | spi->modalias, | |
93 | data, | |
94 | max31722_groups); | |
95 | if (IS_ERR(data->hwmon_dev)) { | |
96 | max31722_set_mode(data, MAX31722_MODE_STANDBY); | |
97 | return PTR_ERR(data->hwmon_dev); | |
98 | } | |
99 | ||
100 | return 0; | |
101 | } | |
102 | ||
a0386bba | 103 | static void max31722_remove(struct spi_device *spi) |
04e1e70a TB |
104 | { |
105 | struct max31722_data *data = spi_get_drvdata(spi); | |
efb389b8 | 106 | int ret; |
04e1e70a TB |
107 | |
108 | hwmon_device_unregister(data->hwmon_dev); | |
109 | ||
efb389b8 UKK |
110 | ret = max31722_set_mode(data, MAX31722_MODE_STANDBY); |
111 | if (ret) | |
112 | /* There is nothing we can do about this ... */ | |
113 | dev_warn(&spi->dev, "Failed to put device in stand-by mode\n"); | |
04e1e70a TB |
114 | } |
115 | ||
80294537 | 116 | static int max31722_suspend(struct device *dev) |
04e1e70a TB |
117 | { |
118 | struct spi_device *spi_device = to_spi_device(dev); | |
119 | struct max31722_data *data = spi_get_drvdata(spi_device); | |
120 | ||
121 | return max31722_set_mode(data, MAX31722_MODE_STANDBY); | |
122 | } | |
123 | ||
80294537 | 124 | static int max31722_resume(struct device *dev) |
04e1e70a TB |
125 | { |
126 | struct spi_device *spi_device = to_spi_device(dev); | |
127 | struct max31722_data *data = spi_get_drvdata(spi_device); | |
128 | ||
129 | return max31722_set_mode(data, MAX31722_MODE_CONTINUOUS); | |
130 | } | |
131 | ||
80294537 | 132 | static DEFINE_SIMPLE_DEV_PM_OPS(max31722_pm_ops, max31722_suspend, max31722_resume); |
04e1e70a TB |
133 | |
134 | static const struct spi_device_id max31722_spi_id[] = { | |
135 | {"max31722", 0}, | |
136 | {"max31723", 0}, | |
137 | {} | |
138 | }; | |
04e1e70a TB |
139 | MODULE_DEVICE_TABLE(spi, max31722_spi_id); |
140 | ||
141 | static struct spi_driver max31722_driver = { | |
142 | .driver = { | |
143 | .name = "max31722", | |
80294537 | 144 | .pm = pm_sleep_ptr(&max31722_pm_ops), |
04e1e70a TB |
145 | }, |
146 | .probe = max31722_probe, | |
147 | .remove = max31722_remove, | |
148 | .id_table = max31722_spi_id, | |
149 | }; | |
150 | ||
151 | module_spi_driver(max31722_driver); | |
152 | ||
153 | MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>"); | |
154 | MODULE_DESCRIPTION("max31722 sensor driver"); | |
155 | MODULE_LICENSE("GPL v2"); |