1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * lm77.c - Part of lm_sensors, Linux kernel modules for hardware |
4 | * monitoring |
5 | * |
6 | * Copyright (c) 2004 Andras BALI <drewie@freemail.hu> |
7 | * |
8 | * Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. The LM77 |
9 | * is a temperature sensor and thermal window comparator with 0.5 deg |
10 | * resolution made by National Semiconductor. Complete datasheet can be |
11 | * obtained at their site: |
12 | * http://www.national.com/pf/LM/LM77.html |
13 | */ |
14 | |
15 | #include <linux/module.h> |
16 | #include <linux/init.h> |
17 | #include <linux/slab.h> |
18 | #include <linux/jiffies.h> |
19 | #include <linux/i2c.h> |
20 | #include <linux/hwmon.h> |
21 | #include <linux/hwmon-sysfs.h> |
22 | #include <linux/err.h> |
23 | #include <linux/mutex.h> |
24 | |
25 | /* Addresses to scan */ |
26 | static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, |
27 | I2C_CLIENT_END }; |
28 | |
29 | /* The LM77 registers */ |
30 | #define LM77_REG_TEMP 0x00 |
31 | #define LM77_REG_CONF 0x01 |
32 | #define LM77_REG_TEMP_HYST 0x02 |
33 | #define LM77_REG_TEMP_CRIT 0x03 |
34 | #define LM77_REG_TEMP_MIN 0x04 |
35 | #define LM77_REG_TEMP_MAX 0x05 |
36 | |
37 | enum temp_index { |
38 | t_input = 0, |
39 | t_crit, |
40 | t_min, |
41 | t_max, |
42 | t_hyst, |
43 | t_num_temp |
44 | }; |
45 | |
46 | static const u8 temp_regs[t_num_temp] = { |
47 | [t_input] = LM77_REG_TEMP, |
48 | [t_min] = LM77_REG_TEMP_MIN, |
49 | [t_max] = LM77_REG_TEMP_MAX, |
50 | [t_crit] = LM77_REG_TEMP_CRIT, |
51 | [t_hyst] = LM77_REG_TEMP_HYST, |
52 | }; |
53 | |
54 | /* Each client has this additional data */ |
55 | struct lm77_data { |
56 | struct i2c_client *client; |
57 | struct mutex update_lock; |
58 | bool valid; |
59 | unsigned long last_updated; /* In jiffies */ |
60 | int temp[t_num_temp]; /* index using temp_index */ |
61 | u8 alarms; |
62 | }; |
63 | |
64 | /* straight from the datasheet */ |
65 | #define LM77_TEMP_MIN (-55000) |
66 | #define LM77_TEMP_MAX 125000 |
67 | |
68 | /* |
69 | * In the temperature registers, the low 3 bits are not part of the |
70 | * temperature values; they are the status bits. |
71 | */ |
72 | static inline s16 LM77_TEMP_TO_REG(int temp) |
73 | { |
74 | return (temp / 500) * 8; |
75 | } |
76 | |
77 | static inline int LM77_TEMP_FROM_REG(s16 reg) |
78 | { |
79 | return (reg / 8) * 500; |
80 | } |
81 | |
82 | /* |
83 | * All registers are word-sized, except for the configuration register. |
84 | * The LM77 uses the high-byte first convention. |
85 | */ |
86 | static u16 lm77_read_value(struct i2c_client *client, u8 reg) |
87 | { |
88 | if (reg == LM77_REG_CONF) |
89 | return i2c_smbus_read_byte_data(client, command: reg); |
90 | else |
91 | return i2c_smbus_read_word_swapped(client, command: reg); |
92 | } |
93 | |
94 | static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) |
95 | { |
96 | if (reg == LM77_REG_CONF) |
97 | return i2c_smbus_write_byte_data(client, command: reg, value); |
98 | else |
99 | return i2c_smbus_write_word_swapped(client, command: reg, value); |
100 | } |
101 | |
102 | static struct lm77_data *lm77_update_device(struct device *dev) |
103 | { |
104 | struct lm77_data *data = dev_get_drvdata(dev); |
105 | struct i2c_client *client = data->client; |
106 | int i; |
107 | |
108 | mutex_lock(&data->update_lock); |
109 | |
110 | if (time_after(jiffies, data->last_updated + HZ + HZ / 2) |
111 | || !data->valid) { |
112 | dev_dbg(&client->dev, "Starting lm77 update\n" ); |
113 | for (i = 0; i < t_num_temp; i++) { |
114 | data->temp[i] = |
115 | LM77_TEMP_FROM_REG(reg: lm77_read_value(client, |
116 | reg: temp_regs[i])); |
117 | } |
118 | data->alarms = |
119 | lm77_read_value(client, LM77_REG_TEMP) & 0x0007; |
120 | data->last_updated = jiffies; |
121 | data->valid = true; |
122 | } |
123 | |
124 | mutex_unlock(lock: &data->update_lock); |
125 | |
126 | return data; |
127 | } |
128 | |
129 | /* sysfs stuff */ |
130 | |
131 | static ssize_t temp_show(struct device *dev, struct device_attribute *devattr, |
132 | char *buf) |
133 | { |
134 | struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); |
135 | struct lm77_data *data = lm77_update_device(dev); |
136 | |
137 | return sprintf(buf, fmt: "%d\n" , data->temp[attr->index]); |
138 | } |
139 | |
140 | static ssize_t temp_hyst_show(struct device *dev, |
141 | struct device_attribute *devattr, char *buf) |
142 | { |
143 | struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); |
144 | struct lm77_data *data = lm77_update_device(dev); |
145 | int nr = attr->index; |
146 | int temp; |
147 | |
148 | temp = nr == t_min ? data->temp[nr] + data->temp[t_hyst] : |
149 | data->temp[nr] - data->temp[t_hyst]; |
150 | |
151 | return sprintf(buf, fmt: "%d\n" , temp); |
152 | } |
153 | |
154 | static ssize_t temp_store(struct device *dev, |
155 | struct device_attribute *devattr, const char *buf, |
156 | size_t count) |
157 | { |
158 | struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); |
159 | struct lm77_data *data = dev_get_drvdata(dev); |
160 | struct i2c_client *client = data->client; |
161 | int nr = attr->index; |
162 | long val; |
163 | int err; |
164 | |
165 | err = kstrtol(s: buf, base: 10, res: &val); |
166 | if (err) |
167 | return err; |
168 | |
169 | val = clamp_val(val, LM77_TEMP_MIN, LM77_TEMP_MAX); |
170 | mutex_lock(&data->update_lock); |
171 | data->temp[nr] = val; |
172 | lm77_write_value(client, reg: temp_regs[nr], value: LM77_TEMP_TO_REG(temp: val)); |
173 | mutex_unlock(lock: &data->update_lock); |
174 | return count; |
175 | } |
176 | |
177 | /* |
178 | * hysteresis is stored as a relative value on the chip, so it has to be |
179 | * converted first. |
180 | */ |
181 | static ssize_t temp_hyst_store(struct device *dev, |
182 | struct device_attribute *devattr, |
183 | const char *buf, size_t count) |
184 | { |
185 | struct lm77_data *data = dev_get_drvdata(dev); |
186 | struct i2c_client *client = data->client; |
187 | long val; |
188 | int err; |
189 | |
190 | err = kstrtol(s: buf, base: 10, res: &val); |
191 | if (err) |
192 | return err; |
193 | |
194 | mutex_lock(&data->update_lock); |
195 | val = clamp_val(data->temp[t_crit] - val, LM77_TEMP_MIN, LM77_TEMP_MAX); |
196 | data->temp[t_hyst] = val; |
197 | lm77_write_value(client, LM77_REG_TEMP_HYST, |
198 | value: LM77_TEMP_TO_REG(temp: data->temp[t_hyst])); |
199 | mutex_unlock(lock: &data->update_lock); |
200 | return count; |
201 | } |
202 | |
203 | static ssize_t alarm_show(struct device *dev, struct device_attribute *attr, |
204 | char *buf) |
205 | { |
206 | int bitnr = to_sensor_dev_attr(attr)->index; |
207 | struct lm77_data *data = lm77_update_device(dev); |
208 | return sprintf(buf, fmt: "%u\n" , (data->alarms >> bitnr) & 1); |
209 | } |
210 | |
211 | static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, t_input); |
212 | static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit); |
213 | static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min); |
214 | static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max); |
215 | |
216 | static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit); |
217 | static SENSOR_DEVICE_ATTR_RO(temp1_min_hyst, temp_hyst, t_min); |
218 | static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max); |
219 | |
220 | static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2); |
221 | static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0); |
222 | static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 1); |
223 | |
224 | static struct attribute *lm77_attrs[] = { |
225 | &sensor_dev_attr_temp1_input.dev_attr.attr, |
226 | &sensor_dev_attr_temp1_crit.dev_attr.attr, |
227 | &sensor_dev_attr_temp1_min.dev_attr.attr, |
228 | &sensor_dev_attr_temp1_max.dev_attr.attr, |
229 | &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr, |
230 | &sensor_dev_attr_temp1_min_hyst.dev_attr.attr, |
231 | &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, |
232 | &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, |
233 | &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, |
234 | &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, |
235 | NULL |
236 | }; |
237 | ATTRIBUTE_GROUPS(lm77); |
238 | |
239 | /* Return 0 if detection is successful, -ENODEV otherwise */ |
240 | static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info) |
241 | { |
242 | struct i2c_adapter *adapter = client->adapter; |
243 | int i, cur, conf, hyst, crit, min, max; |
244 | |
245 | if (!i2c_check_functionality(adap: adapter, I2C_FUNC_SMBUS_BYTE_DATA | |
246 | I2C_FUNC_SMBUS_WORD_DATA)) |
247 | return -ENODEV; |
248 | |
249 | /* |
250 | * Here comes the remaining detection. Since the LM77 has no |
251 | * register dedicated to identification, we have to rely on the |
252 | * following tricks: |
253 | * |
254 | * 1. the high 4 bits represent the sign and thus they should |
255 | * always be the same |
256 | * 2. the high 3 bits are unused in the configuration register |
257 | * 3. addresses 0x06 and 0x07 return the last read value |
258 | * 4. registers cycling over 8-address boundaries |
259 | * |
260 | * Word-sized registers are high-byte first. |
261 | */ |
262 | |
263 | /* addresses cycling */ |
264 | cur = i2c_smbus_read_word_data(client, command: 0); |
265 | conf = i2c_smbus_read_byte_data(client, command: 1); |
266 | hyst = i2c_smbus_read_word_data(client, command: 2); |
267 | crit = i2c_smbus_read_word_data(client, command: 3); |
268 | min = i2c_smbus_read_word_data(client, command: 4); |
269 | max = i2c_smbus_read_word_data(client, command: 5); |
270 | for (i = 8; i <= 0xff; i += 8) { |
271 | if (i2c_smbus_read_byte_data(client, command: i + 1) != conf |
272 | || i2c_smbus_read_word_data(client, command: i + 2) != hyst |
273 | || i2c_smbus_read_word_data(client, command: i + 3) != crit |
274 | || i2c_smbus_read_word_data(client, command: i + 4) != min |
275 | || i2c_smbus_read_word_data(client, command: i + 5) != max) |
276 | return -ENODEV; |
277 | } |
278 | |
279 | /* sign bits */ |
280 | if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) |
281 | || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) |
282 | || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) |
283 | || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) |
284 | || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) |
285 | return -ENODEV; |
286 | |
287 | /* unused bits */ |
288 | if (conf & 0xe0) |
289 | return -ENODEV; |
290 | |
291 | /* 0x06 and 0x07 return the last read value */ |
292 | cur = i2c_smbus_read_word_data(client, command: 0); |
293 | if (i2c_smbus_read_word_data(client, command: 6) != cur |
294 | || i2c_smbus_read_word_data(client, command: 7) != cur) |
295 | return -ENODEV; |
296 | hyst = i2c_smbus_read_word_data(client, command: 2); |
297 | if (i2c_smbus_read_word_data(client, command: 6) != hyst |
298 | || i2c_smbus_read_word_data(client, command: 7) != hyst) |
299 | return -ENODEV; |
300 | min = i2c_smbus_read_word_data(client, command: 4); |
301 | if (i2c_smbus_read_word_data(client, command: 6) != min |
302 | || i2c_smbus_read_word_data(client, command: 7) != min) |
303 | return -ENODEV; |
304 | |
305 | strscpy(info->type, "lm77" , I2C_NAME_SIZE); |
306 | |
307 | return 0; |
308 | } |
309 | |
310 | static void lm77_init_client(struct i2c_client *client) |
311 | { |
312 | /* Initialize the LM77 chip - turn off shutdown mode */ |
313 | int conf = lm77_read_value(client, LM77_REG_CONF); |
314 | if (conf & 1) |
315 | lm77_write_value(client, LM77_REG_CONF, value: conf & 0xfe); |
316 | } |
317 | |
318 | static int lm77_probe(struct i2c_client *client) |
319 | { |
320 | struct device *dev = &client->dev; |
321 | struct device *hwmon_dev; |
322 | struct lm77_data *data; |
323 | |
324 | data = devm_kzalloc(dev, size: sizeof(struct lm77_data), GFP_KERNEL); |
325 | if (!data) |
326 | return -ENOMEM; |
327 | |
328 | data->client = client; |
329 | mutex_init(&data->update_lock); |
330 | |
331 | /* Initialize the LM77 chip */ |
332 | lm77_init_client(client); |
333 | |
334 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, name: client->name, |
335 | drvdata: data, groups: lm77_groups); |
336 | return PTR_ERR_OR_ZERO(ptr: hwmon_dev); |
337 | } |
338 | |
339 | static const struct i2c_device_id lm77_id[] = { |
340 | { "lm77" , 0 }, |
341 | { } |
342 | }; |
343 | MODULE_DEVICE_TABLE(i2c, lm77_id); |
344 | |
345 | /* This is the driver that will be inserted */ |
346 | static struct i2c_driver lm77_driver = { |
347 | .class = I2C_CLASS_HWMON, |
348 | .driver = { |
349 | .name = "lm77" , |
350 | }, |
351 | .probe = lm77_probe, |
352 | .id_table = lm77_id, |
353 | .detect = lm77_detect, |
354 | .address_list = normal_i2c, |
355 | }; |
356 | |
357 | module_i2c_driver(lm77_driver); |
358 | |
359 | MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>" ); |
360 | MODULE_DESCRIPTION("LM77 driver" ); |
361 | MODULE_LICENSE("GPL" ); |
362 | |