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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
761c1770 MS |
2 | /* |
3 | * An hwmon driver for the Microchip TC74 | |
4 | * | |
5 | * Copyright 2015 Maciej Szmigiero <mail@maciej.szmigiero.name> | |
6 | * | |
7 | * Based on ad7414.c: | |
8 | * Copyright 2006 Stefan Roese, DENX Software Engineering | |
9 | * Copyright 2008 Sean MacLennan, PIKA Technologies | |
10 | * Copyright 2008 Frank Edelhaeuser, Spansion Inc. | |
761c1770 MS |
11 | */ |
12 | ||
13 | #include <linux/bitops.h> | |
14 | #include <linux/err.h> | |
15 | #include <linux/hwmon.h> | |
16 | #include <linux/hwmon-sysfs.h> | |
17 | #include <linux/i2c.h> | |
18 | #include <linux/jiffies.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/mutex.h> | |
21 | #include <linux/slab.h> | |
22 | #include <linux/sysfs.h> | |
23 | ||
24 | /* TC74 registers */ | |
25 | #define TC74_REG_TEMP 0x00 | |
26 | #define TC74_REG_CONFIG 0x01 | |
27 | ||
28 | struct tc74_data { | |
29 | struct i2c_client *client; | |
30 | struct mutex lock; /* atomic read data updates */ | |
31 | bool valid; /* validity of fields below */ | |
32 | unsigned long next_update; /* In jiffies */ | |
33 | s8 temp_input; /* Temp value in dC */ | |
34 | }; | |
35 | ||
36 | static int tc74_update_device(struct device *dev) | |
37 | { | |
38 | struct tc74_data *data = dev_get_drvdata(dev); | |
39 | struct i2c_client *client = data->client; | |
40 | int ret; | |
41 | ||
42 | ret = mutex_lock_interruptible(&data->lock); | |
43 | if (ret) | |
44 | return ret; | |
45 | ||
46 | if (time_after(jiffies, data->next_update) || !data->valid) { | |
47 | s32 value; | |
48 | ||
49 | value = i2c_smbus_read_byte_data(client, TC74_REG_CONFIG); | |
50 | if (value < 0) { | |
51 | dev_dbg(&client->dev, "TC74_REG_CONFIG read err %d\n", | |
52 | (int)value); | |
53 | ||
54 | ret = value; | |
55 | goto ret_unlock; | |
56 | } | |
57 | ||
58 | if (!(value & BIT(6))) { | |
59 | /* not ready yet */ | |
60 | ||
61 | ret = -EAGAIN; | |
62 | goto ret_unlock; | |
63 | } | |
64 | ||
65 | value = i2c_smbus_read_byte_data(client, TC74_REG_TEMP); | |
66 | if (value < 0) { | |
67 | dev_dbg(&client->dev, "TC74_REG_TEMP read err %d\n", | |
68 | (int)value); | |
69 | ||
70 | ret = value; | |
71 | goto ret_unlock; | |
72 | } | |
73 | ||
74 | data->temp_input = value; | |
75 | data->next_update = jiffies + HZ / 4; | |
76 | data->valid = true; | |
77 | } | |
78 | ||
79 | ret_unlock: | |
80 | mutex_unlock(&data->lock); | |
81 | ||
82 | return ret; | |
83 | } | |
84 | ||
5abcbc7b | 85 | static ssize_t temp_input_show(struct device *dev, |
761c1770 MS |
86 | struct device_attribute *attr, char *buf) |
87 | { | |
88 | struct tc74_data *data = dev_get_drvdata(dev); | |
89 | int ret; | |
90 | ||
91 | ret = tc74_update_device(dev); | |
92 | if (ret) | |
93 | return ret; | |
94 | ||
95 | return sprintf(buf, "%d\n", data->temp_input * 1000); | |
96 | } | |
5abcbc7b | 97 | static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_input, 0); |
761c1770 MS |
98 | |
99 | static struct attribute *tc74_attrs[] = { | |
100 | &sensor_dev_attr_temp1_input.dev_attr.attr, | |
101 | NULL | |
102 | }; | |
103 | ||
104 | ATTRIBUTE_GROUPS(tc74); | |
105 | ||
67487038 | 106 | static int tc74_probe(struct i2c_client *client) |
761c1770 MS |
107 | { |
108 | struct device *dev = &client->dev; | |
109 | struct tc74_data *data; | |
110 | struct device *hwmon_dev; | |
111 | s32 conf; | |
112 | ||
113 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) | |
114 | return -EOPNOTSUPP; | |
115 | ||
116 | data = devm_kzalloc(dev, sizeof(struct tc74_data), GFP_KERNEL); | |
117 | if (!data) | |
118 | return -ENOMEM; | |
119 | ||
120 | data->client = client; | |
121 | mutex_init(&data->lock); | |
122 | ||
123 | /* Make sure the chip is powered up. */ | |
124 | conf = i2c_smbus_read_byte_data(client, TC74_REG_CONFIG); | |
125 | if (conf < 0) { | |
126 | dev_err(dev, "unable to read config register\n"); | |
127 | ||
128 | return conf; | |
129 | } | |
130 | ||
131 | if (conf & 0x3f) { | |
132 | dev_err(dev, "invalid config register value\n"); | |
133 | ||
134 | return -ENODEV; | |
135 | } | |
136 | ||
137 | if (conf & BIT(7)) { | |
138 | s32 ret; | |
139 | ||
140 | conf &= ~BIT(7); | |
141 | ||
142 | ret = i2c_smbus_write_byte_data(client, TC74_REG_CONFIG, conf); | |
143 | if (ret) | |
144 | dev_warn(dev, "unable to disable STANDBY\n"); | |
145 | } | |
146 | ||
147 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, | |
148 | client->name, | |
149 | data, tc74_groups); | |
150 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
151 | } | |
152 | ||
153 | static const struct i2c_device_id tc74_id[] = { | |
154 | { "tc74", 0 }, | |
155 | {} | |
156 | }; | |
157 | MODULE_DEVICE_TABLE(i2c, tc74_id); | |
158 | ||
159 | static struct i2c_driver tc74_driver = { | |
160 | .driver = { | |
161 | .name = "tc74", | |
162 | }, | |
67487038 | 163 | .probe_new = tc74_probe, |
761c1770 MS |
164 | .id_table = tc74_id, |
165 | }; | |
166 | ||
167 | module_i2c_driver(tc74_driver); | |
168 | ||
169 | MODULE_AUTHOR("Maciej Szmigiero <mail@maciej.szmigiero.name>"); | |
170 | ||
171 | MODULE_DESCRIPTION("TC74 driver"); | |
172 | MODULE_LICENSE("GPL"); |