1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware
4 *               monitoring
5 * Copyright (C) 2003-2009  Jean Delvare <jdelvare@suse.de>
6 *
7 * Inspired from the lm83 driver. The W83L785TS-S is a sensor chip made
8 * by Winbond. It reports a single external temperature with a 1 deg
9 * resolution and a 3 deg accuracy. Datasheet can be obtained from
10 * Winbond's website at:
11 *   http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83L785TS-S.pdf
12 *
13 * Ported to Linux 2.6 by Wolfgang Ziegler <nuppla@gmx.at> and Jean Delvare
14 * <jdelvare@suse.de>.
15 *
16 * Thanks to James Bolt <james@evilpenguin.com> for benchmarking the read
17 * error handling mechanism.
18 */
19
20#include <linux/module.h>
21#include <linux/delay.h>
22#include <linux/init.h>
23#include <linux/slab.h>
24#include <linux/jiffies.h>
25#include <linux/i2c.h>
26#include <linux/hwmon.h>
27#include <linux/hwmon-sysfs.h>
28#include <linux/err.h>
29#include <linux/mutex.h>
30
31/* How many retries on register read error */
32#define MAX_RETRIES	5
33
34/*
35 * Address to scan
36 * Address is fully defined internally and cannot be changed.
37 */
38
39static const unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };
40
41/*
42 * The W83L785TS-S registers
43 * Manufacturer ID is 0x5CA3 for Winbond.
44 */
45
46#define W83L785TS_REG_MAN_ID1		0x4D
47#define W83L785TS_REG_MAN_ID2		0x4C
48#define W83L785TS_REG_CHIP_ID		0x4E
49#define W83L785TS_REG_CONFIG		0x40
50#define W83L785TS_REG_TYPE		0x52
51#define W83L785TS_REG_TEMP		0x27
52#define W83L785TS_REG_TEMP_OVER		0x53 /* not sure about this one */
53
54/*
55 * Conversions
56 * The W83L785TS-S uses signed 8-bit values.
57 */
58
59#define TEMP_FROM_REG(val)	((val) * 1000)
60
61/*
62 * Functions declaration
63 */
64
65static int w83l785ts_probe(struct i2c_client *client);
66static int w83l785ts_detect(struct i2c_client *client,
67			    struct i2c_board_info *info);
68static int w83l785ts_remove(struct i2c_client *client);
69static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
70static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
71
72/*
73 * Driver data (common to all clients)
74 */
75
76static const struct i2c_device_id w83l785ts_id[] = {
77	{ "w83l785ts", 0 },
78	{ }
79};
80MODULE_DEVICE_TABLE(i2c, w83l785ts_id);
81
82static struct i2c_driver w83l785ts_driver = {
83	.class		= I2C_CLASS_HWMON,
84	.driver = {
85		.name	= "w83l785ts",
86	},
87	.probe_new	= w83l785ts_probe,
88	.remove		= w83l785ts_remove,
89	.id_table	= w83l785ts_id,
90	.detect		= w83l785ts_detect,
91	.address_list	= normal_i2c,
92};
93
94/*
95 * Client data (each client gets its own)
96 */
97
98struct w83l785ts_data {
99	struct device *hwmon_dev;
100	struct mutex update_lock;
101	char valid; /* zero until following fields are valid */
102	unsigned long last_updated; /* in jiffies */
103
104	/* registers values */
105	s8 temp[2]; /* 0: input, 1: critical limit */
106};
107
108/*
109 * Sysfs stuff
110 */
111
112static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
113	char *buf)
114{
115	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
116	struct w83l785ts_data *data = w83l785ts_update_device(dev);
117	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
118}
119
120static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
121static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
122
123/*
124 * Real code
125 */
126
127/* Return 0 if detection is successful, -ENODEV otherwise */
128static int w83l785ts_detect(struct i2c_client *client,
129			    struct i2c_board_info *info)
130{
131	struct i2c_adapter *adapter = client->adapter;
132	u16 man_id;
133	u8 chip_id;
134
135	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
136		return -ENODEV;
137
138	/* detection */
139	if ((w83l785ts_read_value(client, W83L785TS_REG_CONFIG, 0) & 0x80)
140	 || (w83l785ts_read_value(client, W83L785TS_REG_TYPE, 0) & 0xFC)) {
141		dev_dbg(&adapter->dev,
142			"W83L785TS-S detection failed at 0x%02x\n",
143			client->addr);
144		return -ENODEV;
145	}
146
147	/* Identification */
148	man_id = (w83l785ts_read_value(client, W83L785TS_REG_MAN_ID1, 0) << 8)
149	       + w83l785ts_read_value(client, W83L785TS_REG_MAN_ID2, 0);
150	chip_id = w83l785ts_read_value(client, W83L785TS_REG_CHIP_ID, 0);
151
152	if (man_id != 0x5CA3		/* Winbond */
153	 || chip_id != 0x70) {		/* W83L785TS-S */
154		dev_dbg(&adapter->dev,
155			"Unsupported chip (man_id=0x%04X, chip_id=0x%02X)\n",
156			man_id, chip_id);
157		return -ENODEV;
158	}
159
160	strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);
161
162	return 0;
163}
164
165static int w83l785ts_probe(struct i2c_client *client)
166{
167	struct w83l785ts_data *data;
168	struct device *dev = &client->dev;
169	int err;
170
171	data = devm_kzalloc(dev, sizeof(struct w83l785ts_data), GFP_KERNEL);
172	if (!data)
173		return -ENOMEM;
174
175	i2c_set_clientdata(client, data);
176	mutex_init(&data->update_lock);
177
178	/*
179	 * Initialize the W83L785TS chip
180	 * Nothing yet, assume it is already started.
181	 */
182
183	err = device_create_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
184	if (err)
185		return err;
186
187	err = device_create_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
188	if (err)
189		goto exit_remove;
190
191	/* Register sysfs hooks */
192	data->hwmon_dev = hwmon_device_register(dev);
193	if (IS_ERR(data->hwmon_dev)) {
194		err = PTR_ERR(data->hwmon_dev);
195		goto exit_remove;
196	}
197
198	return 0;
199
200exit_remove:
201	device_remove_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
202	device_remove_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
203	return err;
204}
205
206static int w83l785ts_remove(struct i2c_client *client)
207{
208	struct w83l785ts_data *data = i2c_get_clientdata(client);
209
210	hwmon_device_unregister(data->hwmon_dev);
211	device_remove_file(&client->dev,
212			   &sensor_dev_attr_temp1_input.dev_attr);
213	device_remove_file(&client->dev,
214			   &sensor_dev_attr_temp1_max.dev_attr);
215
216	return 0;
217}
218
219static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
220{
221	int value, i;
222	struct device *dev;
223	const char *prefix;
224
225	/*
226	 * We might be called during detection, at which point the client
227	 * isn't yet fully initialized, so we can't use dev_dbg on it
228	 */
229	if (i2c_get_clientdata(client)) {
230		dev = &client->dev;
231		prefix = "";
232	} else {
233		dev = &client->adapter->dev;
234		prefix = "w83l785ts: ";
235	}
236
237	/*
238	 * Frequent read errors have been reported on Asus boards, so we
239	 * retry on read errors. If it still fails (unlikely), return the
240	 * default value requested by the caller.
241	 */
242	for (i = 1; i <= MAX_RETRIES; i++) {
243		value = i2c_smbus_read_byte_data(client, reg);
244		if (value >= 0) {
245			dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
246				prefix, value, reg);
247			return value;
248		}
249		dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
250		msleep(i);
251	}
252
253	dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
254		reg);
255	return defval;
256}
257
258static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
259{
260	struct i2c_client *client = to_i2c_client(dev);
261	struct w83l785ts_data *data = i2c_get_clientdata(client);
262
263	mutex_lock(&data->update_lock);
264
265	if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
266		dev_dbg(&client->dev, "Updating w83l785ts data.\n");
267		data->temp[0] = w83l785ts_read_value(client,
268				W83L785TS_REG_TEMP, data->temp[0]);
269		data->temp[1] = w83l785ts_read_value(client,
270				W83L785TS_REG_TEMP_OVER, data->temp[1]);
271
272		data->last_updated = jiffies;
273		data->valid = 1;
274	}
275
276	mutex_unlock(&data->update_lock);
277
278	return data;
279}
280
281module_i2c_driver(w83l785ts_driver);
282
283MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
284MODULE_DESCRIPTION("W83L785TS-S driver");
285MODULE_LICENSE("GPL");
286