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