xref: /openbmc/linux/drivers/hwmon/max6642.c (revision 1975d167)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Driver for +/-1 degree C, SMBus-Compatible Remote/Local Temperature Sensor
4  * with Overtemperature Alarm
5  *
6  * Copyright (C) 2011 AppearTV AS
7  *
8  * Derived from:
9  *
10  *  Based on the max1619 driver.
11  *  Copyright (C) 2003-2004 Oleksij Rempel <bug-track@fisher-privat.net>
12  *                          Jean Delvare <jdelvare@suse.de>
13  *
14  * The MAX6642 is a sensor chip made by Maxim.
15  * It reports up to two temperatures (its own plus up to
16  * one external one). Complete datasheet can be
17  * obtained from Maxim's website at:
18  *   http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf
19  */
20 
21 
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/slab.h>
25 #include <linux/jiffies.h>
26 #include <linux/i2c.h>
27 #include <linux/hwmon.h>
28 #include <linux/hwmon-sysfs.h>
29 #include <linux/err.h>
30 #include <linux/mutex.h>
31 #include <linux/sysfs.h>
32 
33 static const unsigned short normal_i2c[] = {
34 	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
35 
36 /*
37  * The MAX6642 registers
38  */
39 
40 #define MAX6642_REG_R_MAN_ID		0xFE
41 #define MAX6642_REG_R_CONFIG		0x03
42 #define MAX6642_REG_W_CONFIG		0x09
43 #define MAX6642_REG_R_STATUS		0x02
44 #define MAX6642_REG_R_LOCAL_TEMP	0x00
45 #define MAX6642_REG_R_LOCAL_TEMPL	0x11
46 #define MAX6642_REG_R_LOCAL_HIGH	0x05
47 #define MAX6642_REG_W_LOCAL_HIGH	0x0B
48 #define MAX6642_REG_R_REMOTE_TEMP	0x01
49 #define MAX6642_REG_R_REMOTE_TEMPL	0x10
50 #define MAX6642_REG_R_REMOTE_HIGH	0x07
51 #define MAX6642_REG_W_REMOTE_HIGH	0x0D
52 
53 /*
54  * Conversions
55  */
56 
temp_from_reg10(int val)57 static int temp_from_reg10(int val)
58 {
59 	return val * 250;
60 }
61 
temp_from_reg(int val)62 static int temp_from_reg(int val)
63 {
64 	return val * 1000;
65 }
66 
temp_to_reg(int val)67 static int temp_to_reg(int val)
68 {
69 	return val / 1000;
70 }
71 
72 /*
73  * Client data (each client gets its own)
74  */
75 
76 struct max6642_data {
77 	struct i2c_client *client;
78 	struct mutex update_lock;
79 	bool valid; /* zero until following fields are valid */
80 	unsigned long last_updated; /* in jiffies */
81 
82 	/* registers values */
83 	u16 temp_input[2]; /* local/remote */
84 	u16 temp_high[2]; /* local/remote */
85 	u8 alarms;
86 };
87 
88 /*
89  * Real code
90  */
91 
max6642_init_client(struct max6642_data * data,struct i2c_client * client)92 static void max6642_init_client(struct max6642_data *data,
93 				struct i2c_client *client)
94 {
95 	u8 config;
96 
97 	/*
98 	 * Start the conversions.
99 	 */
100 	config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
101 	if (config & 0x40)
102 		i2c_smbus_write_byte_data(client, MAX6642_REG_W_CONFIG,
103 					  config & 0xBF); /* run */
104 
105 	data->temp_high[0] = i2c_smbus_read_byte_data(client,
106 				MAX6642_REG_R_LOCAL_HIGH);
107 	data->temp_high[1] = i2c_smbus_read_byte_data(client,
108 				MAX6642_REG_R_REMOTE_HIGH);
109 }
110 
111 /* Return 0 if detection is successful, -ENODEV otherwise */
max6642_detect(struct i2c_client * client,struct i2c_board_info * info)112 static int max6642_detect(struct i2c_client *client,
113 			  struct i2c_board_info *info)
114 {
115 	struct i2c_adapter *adapter = client->adapter;
116 	u8 reg_config, reg_status, man_id;
117 
118 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
119 		return -ENODEV;
120 
121 	/* identification */
122 	man_id = i2c_smbus_read_byte_data(client, MAX6642_REG_R_MAN_ID);
123 	if (man_id != 0x4D)
124 		return -ENODEV;
125 
126 	/* sanity check */
127 	if (i2c_smbus_read_byte_data(client, 0x04) != 0x4D
128 	    || i2c_smbus_read_byte_data(client, 0x06) != 0x4D
129 	    || i2c_smbus_read_byte_data(client, 0xff) != 0x4D)
130 		return -ENODEV;
131 
132 	/*
133 	 * We read the config and status register, the 4 lower bits in the
134 	 * config register should be zero and bit 5, 3, 1 and 0 should be
135 	 * zero in the status register.
136 	 */
137 	reg_config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
138 	if ((reg_config & 0x0f) != 0x00)
139 		return -ENODEV;
140 
141 	/* in between, another round of sanity checks */
142 	if (i2c_smbus_read_byte_data(client, 0x04) != reg_config
143 	    || i2c_smbus_read_byte_data(client, 0x06) != reg_config
144 	    || i2c_smbus_read_byte_data(client, 0xff) != reg_config)
145 		return -ENODEV;
146 
147 	reg_status = i2c_smbus_read_byte_data(client, MAX6642_REG_R_STATUS);
148 	if ((reg_status & 0x2b) != 0x00)
149 		return -ENODEV;
150 
151 	strscpy(info->type, "max6642", I2C_NAME_SIZE);
152 
153 	return 0;
154 }
155 
max6642_update_device(struct device * dev)156 static struct max6642_data *max6642_update_device(struct device *dev)
157 {
158 	struct max6642_data *data = dev_get_drvdata(dev);
159 	struct i2c_client *client = data->client;
160 	u16 val, tmp;
161 
162 	mutex_lock(&data->update_lock);
163 
164 	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
165 		dev_dbg(dev, "Updating max6642 data.\n");
166 		val = i2c_smbus_read_byte_data(client,
167 					MAX6642_REG_R_LOCAL_TEMPL);
168 		tmp = (val >> 6) & 3;
169 		val = i2c_smbus_read_byte_data(client,
170 					MAX6642_REG_R_LOCAL_TEMP);
171 		val = (val << 2) | tmp;
172 		data->temp_input[0] = val;
173 		val = i2c_smbus_read_byte_data(client,
174 					MAX6642_REG_R_REMOTE_TEMPL);
175 		tmp = (val >> 6) & 3;
176 		val = i2c_smbus_read_byte_data(client,
177 					MAX6642_REG_R_REMOTE_TEMP);
178 		val = (val << 2) | tmp;
179 		data->temp_input[1] = val;
180 		data->alarms = i2c_smbus_read_byte_data(client,
181 					MAX6642_REG_R_STATUS);
182 
183 		data->last_updated = jiffies;
184 		data->valid = true;
185 	}
186 
187 	mutex_unlock(&data->update_lock);
188 
189 	return data;
190 }
191 
192 /*
193  * Sysfs stuff
194  */
195 
temp_max10_show(struct device * dev,struct device_attribute * dev_attr,char * buf)196 static ssize_t temp_max10_show(struct device *dev,
197 			       struct device_attribute *dev_attr, char *buf)
198 {
199 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
200 	struct max6642_data *data = max6642_update_device(dev);
201 
202 	return sprintf(buf, "%d\n",
203 		       temp_from_reg10(data->temp_input[attr->index]));
204 }
205 
temp_max_show(struct device * dev,struct device_attribute * attr,char * buf)206 static ssize_t temp_max_show(struct device *dev,
207 			     struct device_attribute *attr, char *buf)
208 {
209 	struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
210 	struct max6642_data *data = max6642_update_device(dev);
211 
212 	return sprintf(buf, "%d\n", temp_from_reg(data->temp_high[attr2->nr]));
213 }
214 
temp_max_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)215 static ssize_t temp_max_store(struct device *dev,
216 			      struct device_attribute *attr, const char *buf,
217 			      size_t count)
218 {
219 	struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
220 	struct max6642_data *data = dev_get_drvdata(dev);
221 	unsigned long val;
222 	int err;
223 
224 	err = kstrtoul(buf, 10, &val);
225 	if (err < 0)
226 		return err;
227 
228 	mutex_lock(&data->update_lock);
229 	data->temp_high[attr2->nr] = clamp_val(temp_to_reg(val), 0, 255);
230 	i2c_smbus_write_byte_data(data->client, attr2->index,
231 				  data->temp_high[attr2->nr]);
232 	mutex_unlock(&data->update_lock);
233 	return count;
234 }
235 
alarm_show(struct device * dev,struct device_attribute * attr,char * buf)236 static ssize_t alarm_show(struct device *dev, struct device_attribute *attr,
237 			  char *buf)
238 {
239 	int bitnr = to_sensor_dev_attr(attr)->index;
240 	struct max6642_data *data = max6642_update_device(dev);
241 	return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
242 }
243 
244 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_max10, 0);
245 static SENSOR_DEVICE_ATTR_RO(temp2_input, temp_max10, 1);
246 static SENSOR_DEVICE_ATTR_2_RW(temp1_max, temp_max, 0,
247 			       MAX6642_REG_W_LOCAL_HIGH);
248 static SENSOR_DEVICE_ATTR_2_RW(temp2_max, temp_max, 1,
249 			       MAX6642_REG_W_REMOTE_HIGH);
250 static SENSOR_DEVICE_ATTR_RO(temp2_fault, alarm, 2);
251 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 6);
252 static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, alarm, 4);
253 
254 static struct attribute *max6642_attrs[] = {
255 	&sensor_dev_attr_temp1_input.dev_attr.attr,
256 	&sensor_dev_attr_temp2_input.dev_attr.attr,
257 	&sensor_dev_attr_temp1_max.dev_attr.attr,
258 	&sensor_dev_attr_temp2_max.dev_attr.attr,
259 
260 	&sensor_dev_attr_temp2_fault.dev_attr.attr,
261 	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
262 	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
263 	NULL
264 };
265 ATTRIBUTE_GROUPS(max6642);
266 
max6642_probe(struct i2c_client * client)267 static int max6642_probe(struct i2c_client *client)
268 {
269 	struct device *dev = &client->dev;
270 	struct max6642_data *data;
271 	struct device *hwmon_dev;
272 
273 	data = devm_kzalloc(dev, sizeof(struct max6642_data), GFP_KERNEL);
274 	if (!data)
275 		return -ENOMEM;
276 
277 	data->client = client;
278 	mutex_init(&data->update_lock);
279 
280 	/* Initialize the MAX6642 chip */
281 	max6642_init_client(data, client);
282 
283 	hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
284 							   client->name, data,
285 							   max6642_groups);
286 	return PTR_ERR_OR_ZERO(hwmon_dev);
287 }
288 
289 /*
290  * Driver data (common to all clients)
291  */
292 
293 static const struct i2c_device_id max6642_id[] = {
294 	{ "max6642", 0 },
295 	{ }
296 };
297 MODULE_DEVICE_TABLE(i2c, max6642_id);
298 
299 static struct i2c_driver max6642_driver = {
300 	.class		= I2C_CLASS_HWMON,
301 	.driver = {
302 		.name	= "max6642",
303 	},
304 	.probe		= max6642_probe,
305 	.id_table	= max6642_id,
306 	.detect		= max6642_detect,
307 	.address_list	= normal_i2c,
308 };
309 
310 module_i2c_driver(max6642_driver);
311 
312 MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
313 MODULE_DESCRIPTION("MAX6642 sensor driver");
314 MODULE_LICENSE("GPL");
315