xref: /openbmc/linux/drivers/hwmon/lm73.c (revision 1975d167)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * LM73 Sensor driver
4  * Based on LM75
5  *
6  * Copyright (C) 2007, CenoSYS (www.cenosys.com).
7  * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu).
8  *
9  * Guillaume Ligneul <guillaume.ligneul@gmail.com>
10  * Adrien Demarez <adrien.demarez@bolloretelecom.eu>
11  * Jeremy Laine <jeremy.laine@bolloretelecom.eu>
12  * Chris Verges <kg4ysn@gmail.com>
13  */
14 
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/i2c.h>
18 #include <linux/hwmon.h>
19 #include <linux/hwmon-sysfs.h>
20 #include <linux/err.h>
21 
22 
23 /* Addresses scanned */
24 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
25 					0x4d, 0x4e, I2C_CLIENT_END };
26 
27 /* LM73 registers */
28 #define LM73_REG_INPUT		0x00
29 #define LM73_REG_CONF		0x01
30 #define LM73_REG_MAX		0x02
31 #define LM73_REG_MIN		0x03
32 #define LM73_REG_CTRL		0x04
33 #define LM73_REG_ID		0x07
34 
35 #define LM73_ID			0x9001	/* 0x0190, byte-swapped */
36 #define DRVNAME			"lm73"
37 #define LM73_TEMP_MIN		(-256000 / 250)
38 #define LM73_TEMP_MAX		(255750 / 250)
39 
40 #define LM73_CTRL_RES_SHIFT	5
41 #define LM73_CTRL_RES_MASK	(BIT(5) | BIT(6))
42 #define LM73_CTRL_TO_MASK	BIT(7)
43 
44 #define LM73_CTRL_HI_SHIFT	2
45 #define LM73_CTRL_LO_SHIFT	1
46 
47 static const unsigned short lm73_convrates[] = {
48 	14,	/* 11-bits (0.25000 C/LSB): RES1 Bit = 0, RES0 Bit = 0 */
49 	28,	/* 12-bits (0.12500 C/LSB): RES1 Bit = 0, RES0 Bit = 1 */
50 	56,	/* 13-bits (0.06250 C/LSB): RES1 Bit = 1, RES0 Bit = 0 */
51 	112,	/* 14-bits (0.03125 C/LSB): RES1 Bit = 1, RES0 Bit = 1 */
52 };
53 
54 struct lm73_data {
55 	struct i2c_client *client;
56 	struct mutex lock;
57 	u8 ctrl;			/* control register value */
58 };
59 
60 /*-----------------------------------------------------------------------*/
61 
temp_store(struct device * dev,struct device_attribute * da,const char * buf,size_t count)62 static ssize_t temp_store(struct device *dev, struct device_attribute *da,
63 			  const char *buf, size_t count)
64 {
65 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
66 	struct lm73_data *data = dev_get_drvdata(dev);
67 	long temp;
68 	short value;
69 	s32 err;
70 
71 	int status = kstrtol(buf, 10, &temp);
72 	if (status < 0)
73 		return status;
74 
75 	/* Write value */
76 	value = clamp_val(temp / 250, LM73_TEMP_MIN, LM73_TEMP_MAX) << 5;
77 	err = i2c_smbus_write_word_swapped(data->client, attr->index, value);
78 	return (err < 0) ? err : count;
79 }
80 
temp_show(struct device * dev,struct device_attribute * da,char * buf)81 static ssize_t temp_show(struct device *dev, struct device_attribute *da,
82 			 char *buf)
83 {
84 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
85 	struct lm73_data *data = dev_get_drvdata(dev);
86 	int temp;
87 
88 	s32 err = i2c_smbus_read_word_swapped(data->client, attr->index);
89 	if (err < 0)
90 		return err;
91 
92 	/* use integer division instead of equivalent right shift to
93 	   guarantee arithmetic shift and preserve the sign */
94 	temp = (((s16) err) * 250) / 32;
95 	return sysfs_emit(buf, "%d\n", temp);
96 }
97 
convrate_store(struct device * dev,struct device_attribute * da,const char * buf,size_t count)98 static ssize_t convrate_store(struct device *dev, struct device_attribute *da,
99 			      const char *buf, size_t count)
100 {
101 	struct lm73_data *data = dev_get_drvdata(dev);
102 	unsigned long convrate;
103 	s32 err;
104 	int res = 0;
105 
106 	err = kstrtoul(buf, 10, &convrate);
107 	if (err < 0)
108 		return err;
109 
110 	/*
111 	 * Convert the desired conversion rate into register bits.
112 	 * res is already initialized, and everything past the second-to-last
113 	 * value in the array is treated as belonging to the last value
114 	 * in the array.
115 	 */
116 	while (res < (ARRAY_SIZE(lm73_convrates) - 1) &&
117 			convrate > lm73_convrates[res])
118 		res++;
119 
120 	mutex_lock(&data->lock);
121 	data->ctrl &= LM73_CTRL_TO_MASK;
122 	data->ctrl |= res << LM73_CTRL_RES_SHIFT;
123 	err = i2c_smbus_write_byte_data(data->client, LM73_REG_CTRL,
124 					data->ctrl);
125 	mutex_unlock(&data->lock);
126 
127 	if (err < 0)
128 		return err;
129 
130 	return count;
131 }
132 
convrate_show(struct device * dev,struct device_attribute * da,char * buf)133 static ssize_t convrate_show(struct device *dev, struct device_attribute *da,
134 			     char *buf)
135 {
136 	struct lm73_data *data = dev_get_drvdata(dev);
137 	int res;
138 
139 	res = (data->ctrl & LM73_CTRL_RES_MASK) >> LM73_CTRL_RES_SHIFT;
140 	return sysfs_emit(buf, "%hu\n", lm73_convrates[res]);
141 }
142 
maxmin_alarm_show(struct device * dev,struct device_attribute * da,char * buf)143 static ssize_t maxmin_alarm_show(struct device *dev,
144 				 struct device_attribute *da, char *buf)
145 {
146 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
147 	struct lm73_data *data = dev_get_drvdata(dev);
148 	s32 ctrl;
149 
150 	mutex_lock(&data->lock);
151 	ctrl = i2c_smbus_read_byte_data(data->client, LM73_REG_CTRL);
152 	if (ctrl < 0)
153 		goto abort;
154 	data->ctrl = ctrl;
155 	mutex_unlock(&data->lock);
156 
157 	return sysfs_emit(buf, "%d\n", (ctrl >> attr->index) & 1);
158 
159 abort:
160 	mutex_unlock(&data->lock);
161 	return ctrl;
162 }
163 
164 /*-----------------------------------------------------------------------*/
165 
166 /* sysfs attributes for hwmon */
167 
168 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, LM73_REG_MAX);
169 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, LM73_REG_MIN);
170 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, LM73_REG_INPUT);
171 static SENSOR_DEVICE_ATTR_RW(update_interval, convrate, 0);
172 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, maxmin_alarm,
173 			     LM73_CTRL_HI_SHIFT);
174 static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, maxmin_alarm,
175 			     LM73_CTRL_LO_SHIFT);
176 
177 static struct attribute *lm73_attrs[] = {
178 	&sensor_dev_attr_temp1_input.dev_attr.attr,
179 	&sensor_dev_attr_temp1_max.dev_attr.attr,
180 	&sensor_dev_attr_temp1_min.dev_attr.attr,
181 	&sensor_dev_attr_update_interval.dev_attr.attr,
182 	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
183 	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
184 	NULL
185 };
186 ATTRIBUTE_GROUPS(lm73);
187 
188 /*-----------------------------------------------------------------------*/
189 
190 /* device probe and removal */
191 
192 static int
lm73_probe(struct i2c_client * client)193 lm73_probe(struct i2c_client *client)
194 {
195 	struct device *dev = &client->dev;
196 	struct device *hwmon_dev;
197 	struct lm73_data *data;
198 	int ctrl;
199 
200 	data = devm_kzalloc(dev, sizeof(struct lm73_data), GFP_KERNEL);
201 	if (!data)
202 		return -ENOMEM;
203 
204 	data->client = client;
205 	mutex_init(&data->lock);
206 
207 	ctrl = i2c_smbus_read_byte_data(client, LM73_REG_CTRL);
208 	if (ctrl < 0)
209 		return ctrl;
210 	data->ctrl = ctrl;
211 
212 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
213 							   data, lm73_groups);
214 	if (IS_ERR(hwmon_dev))
215 		return PTR_ERR(hwmon_dev);
216 
217 	dev_info(dev, "sensor '%s'\n", client->name);
218 
219 	return 0;
220 }
221 
222 static const struct i2c_device_id lm73_ids[] = {
223 	{ "lm73", 0 },
224 	{ /* LIST END */ }
225 };
226 MODULE_DEVICE_TABLE(i2c, lm73_ids);
227 
228 /* Return 0 if detection is successful, -ENODEV otherwise */
lm73_detect(struct i2c_client * new_client,struct i2c_board_info * info)229 static int lm73_detect(struct i2c_client *new_client,
230 			struct i2c_board_info *info)
231 {
232 	struct i2c_adapter *adapter = new_client->adapter;
233 	int id, ctrl, conf;
234 
235 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
236 					I2C_FUNC_SMBUS_WORD_DATA))
237 		return -ENODEV;
238 
239 	/*
240 	 * Do as much detection as possible with byte reads first, as word
241 	 * reads can confuse other devices.
242 	 */
243 	ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
244 	if (ctrl < 0 || (ctrl & 0x10))
245 		return -ENODEV;
246 
247 	conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);
248 	if (conf < 0 || (conf & 0x0c))
249 		return -ENODEV;
250 
251 	id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);
252 	if (id < 0 || id != (LM73_ID & 0xff))
253 		return -ENODEV;
254 
255 	/* Check device ID */
256 	id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
257 	if (id < 0 || id != LM73_ID)
258 		return -ENODEV;
259 
260 	strscpy(info->type, "lm73", I2C_NAME_SIZE);
261 
262 	return 0;
263 }
264 
265 static const struct of_device_id lm73_of_match[] = {
266 	{
267 		.compatible = "ti,lm73",
268 	},
269 	{ },
270 };
271 
272 MODULE_DEVICE_TABLE(of, lm73_of_match);
273 
274 static struct i2c_driver lm73_driver = {
275 	.class		= I2C_CLASS_HWMON,
276 	.driver = {
277 		.name	= "lm73",
278 		.of_match_table = lm73_of_match,
279 	},
280 	.probe		= lm73_probe,
281 	.id_table	= lm73_ids,
282 	.detect		= lm73_detect,
283 	.address_list	= normal_i2c,
284 };
285 
286 module_i2c_driver(lm73_driver);
287 
288 MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
289 MODULE_DESCRIPTION("LM73 driver");
290 MODULE_LICENSE("GPL");
291