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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 | ||
106 | static int tc74_probe(struct i2c_client *client, | |
107 | const struct i2c_device_id *dev_id) | |
108 | { | |
109 | struct device *dev = &client->dev; | |
110 | struct tc74_data *data; | |
111 | struct device *hwmon_dev; | |
112 | s32 conf; | |
113 | ||
114 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) | |
115 | return -EOPNOTSUPP; | |
116 | ||
117 | data = devm_kzalloc(dev, sizeof(struct tc74_data), GFP_KERNEL); | |
118 | if (!data) | |
119 | return -ENOMEM; | |
120 | ||
121 | data->client = client; | |
122 | mutex_init(&data->lock); | |
123 | ||
124 | /* Make sure the chip is powered up. */ | |
125 | conf = i2c_smbus_read_byte_data(client, TC74_REG_CONFIG); | |
126 | if (conf < 0) { | |
127 | dev_err(dev, "unable to read config register\n"); | |
128 | ||
129 | return conf; | |
130 | } | |
131 | ||
132 | if (conf & 0x3f) { | |
133 | dev_err(dev, "invalid config register value\n"); | |
134 | ||
135 | return -ENODEV; | |
136 | } | |
137 | ||
138 | if (conf & BIT(7)) { | |
139 | s32 ret; | |
140 | ||
141 | conf &= ~BIT(7); | |
142 | ||
143 | ret = i2c_smbus_write_byte_data(client, TC74_REG_CONFIG, conf); | |
144 | if (ret) | |
145 | dev_warn(dev, "unable to disable STANDBY\n"); | |
146 | } | |
147 | ||
148 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, | |
149 | client->name, | |
150 | data, tc74_groups); | |
151 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
152 | } | |
153 | ||
154 | static const struct i2c_device_id tc74_id[] = { | |
155 | { "tc74", 0 }, | |
156 | {} | |
157 | }; | |
158 | MODULE_DEVICE_TABLE(i2c, tc74_id); | |
159 | ||
160 | static struct i2c_driver tc74_driver = { | |
161 | .driver = { | |
162 | .name = "tc74", | |
163 | }, | |
164 | .probe = tc74_probe, | |
165 | .id_table = tc74_id, | |
166 | }; | |
167 | ||
168 | module_i2c_driver(tc74_driver); | |
169 | ||
170 | MODULE_AUTHOR("Maciej Szmigiero <mail@maciej.szmigiero.name>"); | |
171 | ||
172 | MODULE_DESCRIPTION("TC74 driver"); | |
173 | MODULE_LICENSE("GPL"); |