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 | |
57 | static int temp_from_reg10(int val) |
58 | { |
59 | return val * 250; |
60 | } |
61 | |
62 | static int temp_from_reg(int val) |
63 | { |
64 | return val * 1000; |
65 | } |
66 | |
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 | |
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 | value: 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 */ |
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(adap: 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, command: 0x04) != 0x4D |
128 | || i2c_smbus_read_byte_data(client, command: 0x06) != 0x4D |
129 | || i2c_smbus_read_byte_data(client, command: 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, command: 0x04) != reg_config |
143 | || i2c_smbus_read_byte_data(client, command: 0x06) != reg_config |
144 | || i2c_smbus_read_byte_data(client, command: 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 | |
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(lock: &data->update_lock); |
188 | |
189 | return data; |
190 | } |
191 | |
192 | /* |
193 | * Sysfs stuff |
194 | */ |
195 | |
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, fmt: "%d\n" , |
203 | temp_from_reg10(val: data->temp_input[attr->index])); |
204 | } |
205 | |
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, fmt: "%d\n" , temp_from_reg(val: data->temp_high[attr2->nr])); |
213 | } |
214 | |
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(s: buf, base: 10, res: &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(client: data->client, command: attr2->index, |
231 | value: data->temp_high[attr2->nr]); |
232 | mutex_unlock(lock: &data->update_lock); |
233 | return count; |
234 | } |
235 | |
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, fmt: "%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 | |
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, size: 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(dev: &client->dev, |
284 | name: client->name, drvdata: data, |
285 | groups: max6642_groups); |
286 | return PTR_ERR_OR_ZERO(ptr: 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 | |