Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2011 David George <david.george@ska.ac.za>
4 *
5 * based on adm1021.c
6 * some credit to Christoph Scheurer, but largely a rewrite
7 */
8
9#include <linux/bitops.h>
10#include <linux/bits.h>
11#include <linux/err.h>
12#include <linux/hwmon.h>
13#include <linux/i2c.h>
14#include <linux/init.h>
15#include <linux/module.h>
16#include <linux/regmap.h>
17#include <linux/slab.h>
18
19/* Addresses to scan */
20static const unsigned short max1668_addr_list[] = {
21 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };
22
23/* max1668 registers */
24
25#define MAX1668_REG_TEMP(nr) (nr)
26#define MAX1668_REG_STAT1 0x05
27#define MAX1668_REG_STAT2 0x06
28#define MAX1668_REG_MAN_ID 0xfe
29#define MAX1668_REG_DEV_ID 0xff
30
31/* limits */
32
33/* high limits */
34#define MAX1668_REG_LIMH(nr) (0x08 + 2 * (nr))
35/* read low limits */
36#define MAX1668_REG_LIML(nr) (0x09 + 2 * (nr))
37
38/* manufacturer and device ID Constants */
39#define MAN_ID_MAXIM 0x4d
40#define DEV_ID_MAX1668 0x3
41#define DEV_ID_MAX1805 0x5
42#define DEV_ID_MAX1989 0xb
43
44/* read only mode module parameter */
45static bool read_only;
46module_param(read_only, bool, 0);
47MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");
48
49struct max1668_data {
50 struct regmap *regmap;
51 int channels;
52};
53
54static int max1668_read(struct device *dev, enum hwmon_sensor_types type,
55 u32 attr, int channel, long *val)
56{
57 struct max1668_data *data = dev_get_drvdata(dev);
58 struct regmap *regmap = data->regmap;
59 u32 regs[2] = { MAX1668_REG_STAT1, MAX1668_REG_TEMP(channel) };
60 u8 regvals[2];
61 u32 regval;
62 int ret;
63
64 switch (attr) {
65 case hwmon_temp_input:
66 ret = regmap_read(regmap, MAX1668_REG_TEMP(channel), ®val);
67 if (ret)
68 return ret;
69 *val = sign_extend32(regval, 7) * 1000;
70 break;
71 case hwmon_temp_min:
72 ret = regmap_read(regmap, MAX1668_REG_LIML(channel), ®val);
73 if (ret)
74 return ret;
75 *val = sign_extend32(regval, 7) * 1000;
76 break;
77 case hwmon_temp_max:
78 ret = regmap_read(regmap, MAX1668_REG_LIMH(channel), ®val);
79 if (ret)
80 return ret;
81 *val = sign_extend32(regval, 7) * 1000;
82 break;
83 case hwmon_temp_min_alarm:
84 ret = regmap_read(regmap,
85 channel ? MAX1668_REG_STAT2 : MAX1668_REG_STAT1,
86 ®val);
87 if (ret)
88 return ret;
89 if (channel)
90 *val = !!(regval & BIT(9 - channel * 2));
91 else
92 *val = !!(regval & BIT(5));
93 break;
94 case hwmon_temp_max_alarm:
95 ret = regmap_read(regmap,
96 channel ? MAX1668_REG_STAT2 : MAX1668_REG_STAT1,
97 ®val);
98 if (ret)
99 return ret;
100 if (channel)
101 *val = !!(regval & BIT(8 - channel * 2));
102 else
103 *val = !!(regval & BIT(6));
104 break;
105 case hwmon_temp_fault:
106 ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
107 if (ret)
108 return ret;
109 *val = !!((regvals[0] & BIT(4)) && regvals[1] == 127);
110 break;
111 default:
112 return -EOPNOTSUPP;
113 }
114 return 0;
115}
116
117static int max1668_write(struct device *dev, enum hwmon_sensor_types type,
118 u32 attr, int channel, long val)
119{
120 struct max1668_data *data = dev_get_drvdata(dev);
121 struct regmap *regmap = data->regmap;
122
123 val = clamp_val(val / 1000, -128, 127);
124
125 switch (attr) {
126 case hwmon_temp_min:
127 return regmap_write(regmap, MAX1668_REG_LIML(channel), val);
128 case hwmon_temp_max:
129 return regmap_write(regmap, MAX1668_REG_LIMH(channel), val);
130 default:
131 return -EOPNOTSUPP;
132 }
133}
134
135static umode_t max1668_is_visible(const void *_data, enum hwmon_sensor_types type,
136 u32 attr, int channel)
137{
138 const struct max1668_data *data = _data;
139
140 if (channel >= data->channels)
141 return 0;
142
143 switch (attr) {
144 case hwmon_temp_min:
145 case hwmon_temp_max:
146 return read_only ? 0444 : 0644;
147 case hwmon_temp_input:
148 case hwmon_temp_min_alarm:
149 case hwmon_temp_max_alarm:
150 return 0444;
151 case hwmon_temp_fault:
152 if (channel)
153 return 0444;
154 break;
155 default:
156 break;
157 }
158 return 0;
159}
160
161static const struct hwmon_channel_info * const max1668_info[] = {
162 HWMON_CHANNEL_INFO(temp,
163 HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
164 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM,
165 HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
166 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
167 HWMON_T_FAULT,
168 HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
169 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
170 HWMON_T_FAULT,
171 HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
172 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
173 HWMON_T_FAULT,
174 HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
175 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
176 HWMON_T_FAULT),
177 NULL
178};
179
180static const struct hwmon_ops max1668_hwmon_ops = {
181 .is_visible = max1668_is_visible,
182 .read = max1668_read,
183 .write = max1668_write,
184};
185
186static const struct hwmon_chip_info max1668_chip_info = {
187 .ops = &max1668_hwmon_ops,
188 .info = max1668_info,
189};
190
191/* Return 0 if detection is successful, -ENODEV otherwise */
192static int max1668_detect(struct i2c_client *client,
193 struct i2c_board_info *info)
194{
195 struct i2c_adapter *adapter = client->adapter;
196 const char *type_name;
197 int man_id, dev_id;
198
199 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
200 return -ENODEV;
201
202 /* Check for unsupported part */
203 man_id = i2c_smbus_read_byte_data(client, MAX1668_REG_MAN_ID);
204 if (man_id != MAN_ID_MAXIM)
205 return -ENODEV;
206
207 dev_id = i2c_smbus_read_byte_data(client, MAX1668_REG_DEV_ID);
208 if (dev_id < 0)
209 return -ENODEV;
210
211 type_name = NULL;
212 if (dev_id == DEV_ID_MAX1668)
213 type_name = "max1668";
214 else if (dev_id == DEV_ID_MAX1805)
215 type_name = "max1805";
216 else if (dev_id == DEV_ID_MAX1989)
217 type_name = "max1989";
218
219 if (!type_name)
220 return -ENODEV;
221
222 strscpy(info->type, type_name, I2C_NAME_SIZE);
223
224 return 0;
225}
226
227/* regmap */
228
229static int max1668_reg_read(void *context, unsigned int reg, unsigned int *val)
230{
231 int ret;
232
233 ret = i2c_smbus_read_byte_data(context, reg);
234 if (ret < 0)
235 return ret;
236
237 *val = ret;
238 return 0;
239}
240
241static int max1668_reg_write(void *context, unsigned int reg, unsigned int val)
242{
243 return i2c_smbus_write_byte_data(context, reg + 11, val);
244}
245
246static bool max1668_regmap_is_volatile(struct device *dev, unsigned int reg)
247{
248 return reg <= MAX1668_REG_STAT2;
249}
250
251static bool max1668_regmap_is_writeable(struct device *dev, unsigned int reg)
252{
253 return reg > MAX1668_REG_STAT2 && reg <= MAX1668_REG_LIML(4);
254}
255
256static const struct regmap_config max1668_regmap_config = {
257 .reg_bits = 8,
258 .val_bits = 8,
259 .cache_type = REGCACHE_MAPLE,
260 .volatile_reg = max1668_regmap_is_volatile,
261 .writeable_reg = max1668_regmap_is_writeable,
262};
263
264static const struct regmap_bus max1668_regmap_bus = {
265 .reg_write = max1668_reg_write,
266 .reg_read = max1668_reg_read,
267};
268
269static int max1668_probe(struct i2c_client *client)
270{
271 struct i2c_adapter *adapter = client->adapter;
272 struct device *dev = &client->dev;
273 struct device *hwmon_dev;
274 struct max1668_data *data;
275
276 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
277 return -ENODEV;
278
279 data = devm_kzalloc(dev, sizeof(struct max1668_data), GFP_KERNEL);
280 if (!data)
281 return -ENOMEM;
282
283 data->regmap = devm_regmap_init(dev, &max1668_regmap_bus, client,
284 &max1668_regmap_config);
285 if (IS_ERR(data->regmap))
286 return PTR_ERR(data->regmap);
287
288 data->channels = (uintptr_t)i2c_get_match_data(client);
289
290 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
291 &max1668_chip_info, NULL);
292 return PTR_ERR_OR_ZERO(hwmon_dev);
293}
294
295static const struct i2c_device_id max1668_id[] = {
296 { "max1668", 5 },
297 { "max1805", 3 },
298 { "max1989", 5 },
299 { }
300};
301MODULE_DEVICE_TABLE(i2c, max1668_id);
302
303/* This is the driver that will be inserted */
304static struct i2c_driver max1668_driver = {
305 .class = I2C_CLASS_HWMON,
306 .driver = {
307 .name = "max1668",
308 },
309 .probe = max1668_probe,
310 .id_table = max1668_id,
311 .detect = max1668_detect,
312 .address_list = max1668_addr_list,
313};
314
315module_i2c_driver(max1668_driver);
316
317MODULE_AUTHOR("David George <david.george@ska.ac.za>");
318MODULE_DESCRIPTION("MAX1668 remote temperature sensor driver");
319MODULE_LICENSE("GPL");