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/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: &buf, len: 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 | |
49 | static ssize_t max31722_temp_show(struct device *dev, |
50 | struct device_attribute *attr, char *buf) |
51 | { |
52 | ssize_t ret; |
53 | struct max31722_data *data = dev_get_drvdata(dev); |
54 | |
55 | ret = spi_w8r16(spi: 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, fmt: "%d\n" , (s16)le16_to_cpu(ret) * 125 / 32); |
60 | } |
61 | |
62 | static SENSOR_DEVICE_ATTR_RO(temp1_input, max31722_temp, 0); |
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(dev: &spi->dev, size: 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(dev: &spi->dev, |
92 | name: spi->modalias, |
93 | drvdata: data, |
94 | groups: max31722_groups); |
95 | if (IS_ERR(ptr: data->hwmon_dev)) { |
96 | max31722_set_mode(data, MAX31722_MODE_STANDBY); |
97 | return PTR_ERR(ptr: data->hwmon_dev); |
98 | } |
99 | |
100 | return 0; |
101 | } |
102 | |
103 | static void max31722_remove(struct spi_device *spi) |
104 | { |
105 | struct max31722_data *data = spi_get_drvdata(spi); |
106 | int ret; |
107 | |
108 | hwmon_device_unregister(dev: data->hwmon_dev); |
109 | |
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" ); |
114 | } |
115 | |
116 | static int max31722_suspend(struct device *dev) |
117 | { |
118 | struct spi_device *spi_device = to_spi_device(dev); |
119 | struct max31722_data *data = spi_get_drvdata(spi: spi_device); |
120 | |
121 | return max31722_set_mode(data, MAX31722_MODE_STANDBY); |
122 | } |
123 | |
124 | static int max31722_resume(struct device *dev) |
125 | { |
126 | struct spi_device *spi_device = to_spi_device(dev); |
127 | struct max31722_data *data = spi_get_drvdata(spi: spi_device); |
128 | |
129 | return max31722_set_mode(data, MAX31722_MODE_CONTINUOUS); |
130 | } |
131 | |
132 | static DEFINE_SIMPLE_DEV_PM_OPS(max31722_pm_ops, max31722_suspend, max31722_resume); |
133 | |
134 | static const struct spi_device_id max31722_spi_id[] = { |
135 | {"max31722" , 0}, |
136 | {"max31723" , 0}, |
137 | {} |
138 | }; |
139 | MODULE_DEVICE_TABLE(spi, max31722_spi_id); |
140 | |
141 | static struct spi_driver max31722_driver = { |
142 | .driver = { |
143 | .name = "max31722" , |
144 | .pm = pm_sleep_ptr(&max31722_pm_ops), |
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" ); |
156 | |