1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * lm92 - Hardware monitoring driver
4 * Copyright (C) 2005-2008  Jean Delvare <jdelvare@suse.de>
5 *
6 * Based on the lm90 driver, with some ideas taken from the lm_sensors
7 * lm92 driver as well.
8 *
9 * The LM92 is a sensor chip made by National Semiconductor. It reports
10 * its own temperature with a 0.0625 deg resolution and a 0.33 deg
11 * accuracy. Complete datasheet can be obtained from National's website
12 * at:
13 *   http://www.national.com/pf/LM/LM92.html
14 *
15 * This driver also supports the MAX6635 sensor chip made by Maxim.
16 * This chip is compatible with the LM92, but has a lesser accuracy
17 * (1.0 deg). Complete datasheet can be obtained from Maxim's website
18 * at:
19 *   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
20 *
21 * Since the LM92 was the first chipset supported by this driver, most
22 * comments will refer to this chipset, but are actually general and
23 * concern all supported chipsets, unless mentioned otherwise.
24 *
25 * Support could easily be added for the National Semiconductor LM76
26 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
27 * with the LM92.
28 */
29
30#include <linux/module.h>
31#include <linux/init.h>
32#include <linux/slab.h>
33#include <linux/i2c.h>
34#include <linux/hwmon.h>
35#include <linux/hwmon-sysfs.h>
36#include <linux/err.h>
37#include <linux/mutex.h>
38#include <linux/jiffies.h>
39
40/*
41 * The LM92 and MAX6635 have 2 two-state pins for address selection,
42 * resulting in 4 possible addresses.
43 */
44static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
45						I2C_CLIENT_END };
46enum chips { lm92, max6635 };
47
48/* The LM92 registers */
49#define LM92_REG_CONFIG			0x01 /* 8-bit, RW */
50#define LM92_REG_TEMP			0x00 /* 16-bit, RO */
51#define LM92_REG_TEMP_HYST		0x02 /* 16-bit, RW */
52#define LM92_REG_TEMP_CRIT		0x03 /* 16-bit, RW */
53#define LM92_REG_TEMP_LOW		0x04 /* 16-bit, RW */
54#define LM92_REG_TEMP_HIGH		0x05 /* 16-bit, RW */
55#define LM92_REG_MAN_ID			0x07 /* 16-bit, RO, LM92 only */
56
57/*
58 * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
59 * left-justified in 16-bit registers. No rounding is done, with such
60 * a resolution it's just not worth it. Note that the MAX6635 doesn't
61 * make use of the 4 lower bits for limits (i.e. effective resolution
62 * for limits is 1 degree Celsius).
63 */
64static inline int TEMP_FROM_REG(s16 reg)
65{
66	return reg / 8 * 625 / 10;
67}
68
69static inline s16 TEMP_TO_REG(long val)
70{
71	val = clamp_val(val, -60000, 160000);
72	return val * 10 / 625 * 8;
73}
74
75/* Alarm flags are stored in the 3 LSB of the temperature register */
76static inline u8 ALARMS_FROM_REG(s16 reg)
77{
78	return reg & 0x0007;
79}
80
81enum temp_index {
82	t_input,
83	t_crit,
84	t_min,
85	t_max,
86	t_hyst,
87	t_num_regs
88};
89
90static const u8 regs[t_num_regs] = {
91	[t_input] = LM92_REG_TEMP,
92	[t_crit] = LM92_REG_TEMP_CRIT,
93	[t_min] = LM92_REG_TEMP_LOW,
94	[t_max] = LM92_REG_TEMP_HIGH,
95	[t_hyst] = LM92_REG_TEMP_HYST,
96};
97
98/* Client data (each client gets its own) */
99struct lm92_data {
100	struct i2c_client *client;
101	struct mutex update_lock;
102	bool valid; /* false until following fields are valid */
103	unsigned long last_updated; /* in jiffies */
104
105	/* registers values */
106	s16 temp[t_num_regs];	/* index with enum temp_index */
107};
108
109/*
110 * Sysfs attributes and callback functions
111 */
112
113static struct lm92_data *lm92_update_device(struct device *dev)
114{
115	struct lm92_data *data = dev_get_drvdata(dev);
116	struct i2c_client *client = data->client;
117	int i;
118
119	mutex_lock(&data->update_lock);
120
121	if (time_after(jiffies, data->last_updated + HZ) ||
122	    !data->valid) {
123		dev_dbg(&client->dev, "Updating lm92 data\n");
124		for (i = 0; i < t_num_regs; i++) {
125			data->temp[i] =
126				i2c_smbus_read_word_swapped(client, regs[i]);
127		}
128		data->last_updated = jiffies;
129		data->valid = true;
130	}
131
132	mutex_unlock(&data->update_lock);
133
134	return data;
135}
136
137static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,
138			 char *buf)
139{
140	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
141	struct lm92_data *data = lm92_update_device(dev);
142
143	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
144}
145
146static ssize_t temp_store(struct device *dev,
147			  struct device_attribute *devattr, const char *buf,
148			  size_t count)
149{
150	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
151	struct lm92_data *data = dev_get_drvdata(dev);
152	struct i2c_client *client = data->client;
153	int nr = attr->index;
154	long val;
155	int err;
156
157	err = kstrtol(buf, 10, &val);
158	if (err)
159		return err;
160
161	mutex_lock(&data->update_lock);
162	data->temp[nr] = TEMP_TO_REG(val);
163	i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]);
164	mutex_unlock(&data->update_lock);
165	return count;
166}
167
168static ssize_t temp_hyst_show(struct device *dev,
169			      struct device_attribute *devattr, char *buf)
170{
171	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
172	struct lm92_data *data = lm92_update_device(dev);
173
174	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])
175		       - TEMP_FROM_REG(data->temp[t_hyst]));
176}
177
178static ssize_t temp1_min_hyst_show(struct device *dev,
179				   struct device_attribute *attr, char *buf)
180{
181	struct lm92_data *data = lm92_update_device(dev);
182
183	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min])
184		       + TEMP_FROM_REG(data->temp[t_hyst]));
185}
186
187static ssize_t temp_hyst_store(struct device *dev,
188			       struct device_attribute *devattr,
189			       const char *buf, size_t count)
190{
191	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
192	struct lm92_data *data = dev_get_drvdata(dev);
193	struct i2c_client *client = data->client;
194	long val;
195	int err;
196
197	err = kstrtol(buf, 10, &val);
198	if (err)
199		return err;
200
201	val = clamp_val(val, -120000, 220000);
202	mutex_lock(&data->update_lock);
203	data->temp[t_hyst] =
204		TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val);
205	i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
206				     data->temp[t_hyst]);
207	mutex_unlock(&data->update_lock);
208	return count;
209}
210
211static ssize_t alarms_show(struct device *dev, struct device_attribute *attr,
212			   char *buf)
213{
214	struct lm92_data *data = lm92_update_device(dev);
215
216	return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input]));
217}
218
219static ssize_t alarm_show(struct device *dev, struct device_attribute *attr,
220			  char *buf)
221{
222	int bitnr = to_sensor_dev_attr(attr)->index;
223	struct lm92_data *data = lm92_update_device(dev);
224	return sprintf(buf, "%d\n", (data->temp[t_input] >> bitnr) & 1);
225}
226
227static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, t_input);
228static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit);
229static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit);
230static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min);
231static DEVICE_ATTR_RO(temp1_min_hyst);
232static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max);
233static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max);
234static DEVICE_ATTR_RO(alarms);
235static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2);
236static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0);
237static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 1);
238
239/*
240 * Detection and registration
241 */
242
243static void lm92_init_client(struct i2c_client *client)
244{
245	u8 config;
246
247	/* Start the conversions if needed */
248	config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
249	if (config & 0x01)
250		i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
251					  config & 0xFE);
252}
253
254static struct attribute *lm92_attrs[] = {
255	&sensor_dev_attr_temp1_input.dev_attr.attr,
256	&sensor_dev_attr_temp1_crit.dev_attr.attr,
257	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
258	&sensor_dev_attr_temp1_min.dev_attr.attr,
259	&dev_attr_temp1_min_hyst.attr,
260	&sensor_dev_attr_temp1_max.dev_attr.attr,
261	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
262	&dev_attr_alarms.attr,
263	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
264	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
265	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
266	NULL
267};
268ATTRIBUTE_GROUPS(lm92);
269
270/* Return 0 if detection is successful, -ENODEV otherwise */
271static int lm92_detect(struct i2c_client *new_client,
272		       struct i2c_board_info *info)
273{
274	struct i2c_adapter *adapter = new_client->adapter;
275	u8 config;
276	u16 man_id;
277
278	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
279					    | I2C_FUNC_SMBUS_WORD_DATA))
280		return -ENODEV;
281
282	config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
283	man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
284
285	if ((config & 0xe0) == 0x00 && man_id == 0x0180)
286		pr_info("lm92: Found National Semiconductor LM92 chip\n");
287	else
288		return -ENODEV;
289
290	strscpy(info->type, "lm92", I2C_NAME_SIZE);
291
292	return 0;
293}
294
295static int lm92_probe(struct i2c_client *new_client)
296{
297	struct device *hwmon_dev;
298	struct lm92_data *data;
299
300	data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
301			    GFP_KERNEL);
302	if (!data)
303		return -ENOMEM;
304
305	data->client = new_client;
306	mutex_init(&data->update_lock);
307
308	/* Initialize the chipset */
309	lm92_init_client(new_client);
310
311	hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
312							   new_client->name,
313							   data, lm92_groups);
314	return PTR_ERR_OR_ZERO(hwmon_dev);
315}
316
317/*
318 * Module and driver stuff
319 */
320
321static const struct i2c_device_id lm92_id[] = {
322	{ "lm92", lm92 },
323	{ "max6635", max6635 },
324	{ }
325};
326MODULE_DEVICE_TABLE(i2c, lm92_id);
327
328static struct i2c_driver lm92_driver = {
329	.class		= I2C_CLASS_HWMON,
330	.driver = {
331		.name	= "lm92",
332	},
333	.probe		= lm92_probe,
334	.id_table	= lm92_id,
335	.detect		= lm92_detect,
336	.address_list	= normal_i2c,
337};
338
339module_i2c_driver(lm92_driver);
340
341MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
342MODULE_DESCRIPTION("LM92/MAX6635 driver");
343MODULE_LICENSE("GPL");
344