xref: /openbmc/linux/drivers/hwmon/lm73.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
1 /*
2  * LM73 Sensor driver
3  * Based on LM75
4  *
5  * Copyright (C) 2007, CenoSYS (www.cenosys.com).
6  * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu).
7  *
8  * Guillaume Ligneul <guillaume.ligneul@gmail.com>
9  * Adrien Demarez <adrien.demarez@bolloretelecom.eu>
10  * Jeremy Laine <jeremy.laine@bolloretelecom.eu>
11  *
12  * This software program is licensed subject to the GNU General Public License
13  * (GPL).Version 2,June 1991, available at
14  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
15  */
16 
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/i2c.h>
21 #include <linux/hwmon.h>
22 #include <linux/hwmon-sysfs.h>
23 #include <linux/err.h>
24 
25 
26 /* Addresses scanned */
27 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
28 					0x4d, 0x4e, I2C_CLIENT_END };
29 
30 /* LM73 registers */
31 #define LM73_REG_INPUT		0x00
32 #define LM73_REG_CONF		0x01
33 #define LM73_REG_MAX		0x02
34 #define LM73_REG_MIN		0x03
35 #define LM73_REG_CTRL		0x04
36 #define LM73_REG_ID		0x07
37 
38 #define LM73_ID			0x9001 /* or 0x190 after a swab16() */
39 #define DRVNAME			"lm73"
40 #define LM73_TEMP_MIN		(-40)
41 #define LM73_TEMP_MAX		150
42 
43 /*-----------------------------------------------------------------------*/
44 
45 
46 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
47 			const char *buf, size_t count)
48 {
49 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
50 	struct i2c_client *client = to_i2c_client(dev);
51 	long temp;
52 	short value;
53 
54 	int status = strict_strtol(buf, 10, &temp);
55 	if (status < 0)
56 		return status;
57 
58 	/* Write value */
59 	value = (short) SENSORS_LIMIT(temp/250, (LM73_TEMP_MIN*4),
60 		(LM73_TEMP_MAX*4)) << 5;
61 	i2c_smbus_write_word_data(client, attr->index, swab16(value));
62 	return count;
63 }
64 
65 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
66 			 char *buf)
67 {
68 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
69 	struct i2c_client *client = to_i2c_client(dev);
70 	/* use integer division instead of equivalent right shift to
71 	   guarantee arithmetic shift and preserve the sign */
72 	int temp = ((s16) (swab16(i2c_smbus_read_word_data(client,
73 		attr->index)))*250) / 32;
74 	return sprintf(buf, "%d\n", temp);
75 }
76 
77 
78 /*-----------------------------------------------------------------------*/
79 
80 /* sysfs attributes for hwmon */
81 
82 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
83 			show_temp, set_temp, LM73_REG_MAX);
84 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
85 			show_temp, set_temp, LM73_REG_MIN);
86 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
87 			show_temp, NULL, LM73_REG_INPUT);
88 
89 
90 static struct attribute *lm73_attributes[] = {
91 	&sensor_dev_attr_temp1_input.dev_attr.attr,
92 	&sensor_dev_attr_temp1_max.dev_attr.attr,
93 	&sensor_dev_attr_temp1_min.dev_attr.attr,
94 
95 	NULL
96 };
97 
98 static const struct attribute_group lm73_group = {
99 	.attrs = lm73_attributes,
100 };
101 
102 /*-----------------------------------------------------------------------*/
103 
104 /* device probe and removal */
105 
106 static int
107 lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
108 {
109 	struct device *hwmon_dev;
110 	int status;
111 
112 	/* Register sysfs hooks */
113 	status = sysfs_create_group(&client->dev.kobj, &lm73_group);
114 	if (status)
115 		return status;
116 
117 	hwmon_dev = hwmon_device_register(&client->dev);
118 	if (IS_ERR(hwmon_dev)) {
119 		status = PTR_ERR(hwmon_dev);
120 		goto exit_remove;
121 	}
122 	i2c_set_clientdata(client, hwmon_dev);
123 
124 	dev_info(&client->dev, "%s: sensor '%s'\n",
125 		 dev_name(hwmon_dev), client->name);
126 
127 	return 0;
128 
129 exit_remove:
130 	sysfs_remove_group(&client->dev.kobj, &lm73_group);
131 	return status;
132 }
133 
134 static int lm73_remove(struct i2c_client *client)
135 {
136 	struct device *hwmon_dev = i2c_get_clientdata(client);
137 
138 	hwmon_device_unregister(hwmon_dev);
139 	sysfs_remove_group(&client->dev.kobj, &lm73_group);
140 	i2c_set_clientdata(client, NULL);
141 	return 0;
142 }
143 
144 static const struct i2c_device_id lm73_ids[] = {
145 	{ "lm73", 0 },
146 	{ /* LIST END */ }
147 };
148 MODULE_DEVICE_TABLE(i2c, lm73_ids);
149 
150 /* Return 0 if detection is successful, -ENODEV otherwise */
151 static int lm73_detect(struct i2c_client *new_client,
152 			struct i2c_board_info *info)
153 {
154 	struct i2c_adapter *adapter = new_client->adapter;
155 	u16 id;
156 	u8 ctrl;
157 
158 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
159 					I2C_FUNC_SMBUS_WORD_DATA))
160 		return -ENODEV;
161 
162 	/* Check device ID */
163 	id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
164 	ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
165 	if ((id != LM73_ID) || (ctrl & 0x10))
166 		return -ENODEV;
167 
168 	strlcpy(info->type, "lm73", I2C_NAME_SIZE);
169 
170 	return 0;
171 }
172 
173 static struct i2c_driver lm73_driver = {
174 	.class		= I2C_CLASS_HWMON,
175 	.driver = {
176 		.name	= "lm73",
177 	},
178 	.probe		= lm73_probe,
179 	.remove		= lm73_remove,
180 	.id_table	= lm73_ids,
181 	.detect		= lm73_detect,
182 	.address_list	= normal_i2c,
183 };
184 
185 /* module glue */
186 
187 static int __init sensors_lm73_init(void)
188 {
189 	return i2c_add_driver(&lm73_driver);
190 }
191 
192 static void __exit sensors_lm73_exit(void)
193 {
194 	i2c_del_driver(&lm73_driver);
195 }
196 
197 MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
198 MODULE_DESCRIPTION("LM73 driver");
199 MODULE_LICENSE("GPL");
200 
201 module_init(sensors_lm73_init);
202 module_exit(sensors_lm73_exit);
203