1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2017 IBM Corp.
4 *
5 * Driver for the Nuvoton W83773G SMBus temperature sensor IC.
6 * Supported models: W83773G
7 */
8
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/i2c.h>
12#include <linux/hwmon.h>
13#include <linux/hwmon-sysfs.h>
14#include <linux/err.h>
15#include <linux/of_device.h>
16#include <linux/regmap.h>
17
18/* W83773 has 3 channels */
19#define W83773_CHANNELS				3
20
21/* The W83773 registers */
22#define W83773_CONVERSION_RATE_REG_READ		0x04
23#define W83773_CONVERSION_RATE_REG_WRITE	0x0A
24#define W83773_MANUFACTURER_ID_REG		0xFE
25#define W83773_LOCAL_TEMP			0x00
26
27static const u8 W83773_STATUS[2] = { 0x02, 0x17 };
28
29static const u8 W83773_TEMP_LSB[2] = { 0x10, 0x25 };
30static const u8 W83773_TEMP_MSB[2] = { 0x01, 0x24 };
31
32static const u8 W83773_OFFSET_LSB[2] = { 0x12, 0x16 };
33static const u8 W83773_OFFSET_MSB[2] = { 0x11, 0x15 };
34
35/* this is the number of sensors in the device */
36static const struct i2c_device_id w83773_id[] = {
37	{ "w83773g" },
38	{ }
39};
40
41MODULE_DEVICE_TABLE(i2c, w83773_id);
42
43static const struct of_device_id __maybe_unused w83773_of_match[] = {
44	{
45		.compatible = "nuvoton,w83773g"
46	},
47	{ },
48};
49MODULE_DEVICE_TABLE(of, w83773_of_match);
50
51static inline long temp_of_local(s8 reg)
52{
53	return reg * 1000;
54}
55
56static inline long temp_of_remote(s8 hb, u8 lb)
57{
58	return (hb << 3 | lb >> 5) * 125;
59}
60
61static int get_local_temp(struct regmap *regmap, long *val)
62{
63	unsigned int regval;
64	int ret;
65
66	ret = regmap_read(regmap, W83773_LOCAL_TEMP, &regval);
67	if (ret < 0)
68		return ret;
69
70	*val = temp_of_local(regval);
71	return 0;
72}
73
74static int get_remote_temp(struct regmap *regmap, int index, long *val)
75{
76	unsigned int regval_high;
77	unsigned int regval_low;
78	int ret;
79
80	ret = regmap_read(regmap, W83773_TEMP_MSB[index], &regval_high);
81	if (ret < 0)
82		return ret;
83
84	ret = regmap_read(regmap, W83773_TEMP_LSB[index], &regval_low);
85	if (ret < 0)
86		return ret;
87
88	*val = temp_of_remote(regval_high, regval_low);
89	return 0;
90}
91
92static int get_fault(struct regmap *regmap, int index, long *val)
93{
94	unsigned int regval;
95	int ret;
96
97	ret = regmap_read(regmap, W83773_STATUS[index], &regval);
98	if (ret < 0)
99		return ret;
100
101	*val = (regval & 0x04) >> 2;
102	return 0;
103}
104
105static int get_offset(struct regmap *regmap, int index, long *val)
106{
107	unsigned int regval_high;
108	unsigned int regval_low;
109	int ret;
110
111	ret = regmap_read(regmap, W83773_OFFSET_MSB[index], &regval_high);
112	if (ret < 0)
113		return ret;
114
115	ret = regmap_read(regmap, W83773_OFFSET_LSB[index], &regval_low);
116	if (ret < 0)
117		return ret;
118
119	*val = temp_of_remote(regval_high, regval_low);
120	return 0;
121}
122
123static int set_offset(struct regmap *regmap, int index, long val)
124{
125	int ret;
126	u8 high_byte;
127	u8 low_byte;
128
129	val = clamp_val(val, -127825, 127825);
130	/* offset value equals to (high_byte << 3 | low_byte >> 5) * 125 */
131	val /= 125;
132	high_byte = val >> 3;
133	low_byte = (val & 0x07) << 5;
134
135	ret = regmap_write(regmap, W83773_OFFSET_MSB[index], high_byte);
136	if (ret < 0)
137		return ret;
138
139	return regmap_write(regmap, W83773_OFFSET_LSB[index], low_byte);
140}
141
142static int get_update_interval(struct regmap *regmap, long *val)
143{
144	unsigned int regval;
145	int ret;
146
147	ret = regmap_read(regmap, W83773_CONVERSION_RATE_REG_READ, &regval);
148	if (ret < 0)
149		return ret;
150
151	*val = 16000 >> regval;
152	return 0;
153}
154
155static int set_update_interval(struct regmap *regmap, long val)
156{
157	int rate;
158
159	/*
160	 * For valid rates, interval can be calculated as
161	 *	interval = (1 << (8 - rate)) * 62.5;
162	 * Rounded rate is therefore
163	 *	rate = 8 - __fls(interval * 8 / (62.5 * 7));
164	 * Use clamp_val() to avoid overflows, and to ensure valid input
165	 * for __fls.
166	 */
167	val = clamp_val(val, 62, 16000) * 10;
168	rate = 8 - __fls((val * 8 / (625 * 7)));
169	return regmap_write(regmap, W83773_CONVERSION_RATE_REG_WRITE, rate);
170}
171
172static int w83773_read(struct device *dev, enum hwmon_sensor_types type,
173		       u32 attr, int channel, long *val)
174{
175	struct regmap *regmap = dev_get_drvdata(dev);
176
177	if (type == hwmon_chip) {
178		if (attr == hwmon_chip_update_interval)
179			return get_update_interval(regmap, val);
180		return -EOPNOTSUPP;
181	}
182
183	switch (attr) {
184	case hwmon_temp_input:
185		if (channel == 0)
186			return get_local_temp(regmap, val);
187		return get_remote_temp(regmap, channel - 1, val);
188	case hwmon_temp_fault:
189		return get_fault(regmap, channel - 1, val);
190	case hwmon_temp_offset:
191		return get_offset(regmap, channel - 1, val);
192	default:
193		return -EOPNOTSUPP;
194	}
195}
196
197static int w83773_write(struct device *dev, enum hwmon_sensor_types type,
198			u32 attr, int channel, long val)
199{
200	struct regmap *regmap = dev_get_drvdata(dev);
201
202	if (type == hwmon_chip && attr == hwmon_chip_update_interval)
203		return set_update_interval(regmap, val);
204
205	if (type == hwmon_temp && attr == hwmon_temp_offset)
206		return set_offset(regmap, channel - 1, val);
207
208	return -EOPNOTSUPP;
209}
210
211static umode_t w83773_is_visible(const void *data, enum hwmon_sensor_types type,
212				 u32 attr, int channel)
213{
214	switch (type) {
215	case hwmon_chip:
216		switch (attr) {
217		case hwmon_chip_update_interval:
218			return 0644;
219		}
220		break;
221	case hwmon_temp:
222		switch (attr) {
223		case hwmon_temp_input:
224		case hwmon_temp_fault:
225			return 0444;
226		case hwmon_temp_offset:
227			return 0644;
228		}
229		break;
230	default:
231		break;
232	}
233	return 0;
234}
235
236static const struct hwmon_channel_info *w83773_info[] = {
237	HWMON_CHANNEL_INFO(chip,
238			   HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
239	HWMON_CHANNEL_INFO(temp,
240			   HWMON_T_INPUT,
241			   HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_OFFSET,
242			   HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_OFFSET),
243	NULL
244};
245
246static const struct hwmon_ops w83773_ops = {
247	.is_visible = w83773_is_visible,
248	.read = w83773_read,
249	.write = w83773_write,
250};
251
252static const struct hwmon_chip_info w83773_chip_info = {
253	.ops = &w83773_ops,
254	.info = w83773_info,
255};
256
257static const struct regmap_config w83773_regmap_config = {
258	.reg_bits = 8,
259	.val_bits = 8,
260};
261
262static int w83773_probe(struct i2c_client *client)
263{
264	struct device *dev = &client->dev;
265	struct device *hwmon_dev;
266	struct regmap *regmap;
267	int ret;
268
269	regmap = devm_regmap_init_i2c(client, &w83773_regmap_config);
270	if (IS_ERR(regmap)) {
271		dev_err(dev, "failed to allocate register map\n");
272		return PTR_ERR(regmap);
273	}
274
275	/* Set the conversion rate to 2 Hz */
276	ret = regmap_write(regmap, W83773_CONVERSION_RATE_REG_WRITE, 0x05);
277	if (ret < 0) {
278		dev_err(&client->dev, "error writing config rate register\n");
279		return ret;
280	}
281
282	i2c_set_clientdata(client, regmap);
283
284	hwmon_dev = devm_hwmon_device_register_with_info(dev,
285							 client->name,
286							 regmap,
287							 &w83773_chip_info,
288							 NULL);
289	return PTR_ERR_OR_ZERO(hwmon_dev);
290}
291
292static struct i2c_driver w83773_driver = {
293	.class = I2C_CLASS_HWMON,
294	.driver = {
295		.name	= "w83773g",
296		.of_match_table = of_match_ptr(w83773_of_match),
297	},
298	.probe_new = w83773_probe,
299	.id_table = w83773_id,
300};
301
302module_i2c_driver(w83773_driver);
303
304MODULE_AUTHOR("Lei YU <mine260309@gmail.com>");
305MODULE_DESCRIPTION("W83773G temperature sensor driver");
306MODULE_LICENSE("GPL");
307