1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (c) 2011 David George <david.george@ska.ac.za>
6 * some credit to Christoph Scheurer, but largely a rewrite
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>
19 /* Addresses to scan */
20 static const unsigned short max1668_addr_list[] = {
21 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };
23 /* max1668 registers */
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
34 #define MAX1668_REG_LIMH(nr) (0x08 + 2 * (nr))
36 #define MAX1668_REG_LIML(nr) (0x09 + 2 * (nr))
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
44 /* read only mode module parameter */
45 static bool read_only;
46 module_param(read_only, bool, 0);
47 MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");
50 struct regmap *regmap;
54 static int max1668_read(struct device *dev, enum hwmon_sensor_types type,
55 u32 attr, int channel, long *val)
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) };
65 case hwmon_temp_input:
66 ret = regmap_read(regmap, MAX1668_REG_TEMP(channel), ®val);
69 *val = sign_extend32(regval, 7) * 1000;
72 ret = regmap_read(regmap, MAX1668_REG_LIML(channel), ®val);
75 *val = sign_extend32(regval, 7) * 1000;
78 ret = regmap_read(regmap, MAX1668_REG_LIMH(channel), ®val);
81 *val = sign_extend32(regval, 7) * 1000;
83 case hwmon_temp_min_alarm:
84 ret = regmap_read(regmap,
85 channel ? MAX1668_REG_STAT2 : MAX1668_REG_STAT1,
90 *val = !!(regval & BIT(9 - channel * 2));
92 *val = !!(regval & BIT(5));
94 case hwmon_temp_max_alarm:
95 ret = regmap_read(regmap,
96 channel ? MAX1668_REG_STAT2 : MAX1668_REG_STAT1,
101 *val = !!(regval & BIT(8 - channel * 2));
103 *val = !!(regval & BIT(6));
105 case hwmon_temp_fault:
106 ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
109 *val = !!((regvals[0] & BIT(4)) && regvals[1] == 127);
117 static int max1668_write(struct device *dev, enum hwmon_sensor_types type,
118 u32 attr, int channel, long val)
120 struct max1668_data *data = dev_get_drvdata(dev);
121 struct regmap *regmap = data->regmap;
123 val = clamp_val(val / 1000, -128, 127);
127 return regmap_write(regmap, MAX1668_REG_LIML(channel), val);
129 return regmap_write(regmap, MAX1668_REG_LIMH(channel), val);
135 static umode_t max1668_is_visible(const void *_data, enum hwmon_sensor_types type,
136 u32 attr, int channel)
138 const struct max1668_data *data = _data;
140 if (channel >= data->channels)
146 return read_only ? 0444 : 0644;
147 case hwmon_temp_input:
148 case hwmon_temp_min_alarm:
149 case hwmon_temp_max_alarm:
151 case hwmon_temp_fault:
161 static 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 |
168 HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
169 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
171 HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
172 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
174 HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
175 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
180 static const struct hwmon_ops max1668_hwmon_ops = {
181 .is_visible = max1668_is_visible,
182 .read = max1668_read,
183 .write = max1668_write,
186 static const struct hwmon_chip_info max1668_chip_info = {
187 .ops = &max1668_hwmon_ops,
188 .info = max1668_info,
191 /* Return 0 if detection is successful, -ENODEV otherwise */
192 static int max1668_detect(struct i2c_client *client,
193 struct i2c_board_info *info)
195 struct i2c_adapter *adapter = client->adapter;
196 const char *type_name;
199 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
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)
207 dev_id = i2c_smbus_read_byte_data(client, MAX1668_REG_DEV_ID);
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";
222 strscpy(info->type, type_name, I2C_NAME_SIZE);
229 static int max1668_reg_read(void *context, unsigned int reg, unsigned int *val)
233 ret = i2c_smbus_read_byte_data(context, reg);
241 static int max1668_reg_write(void *context, unsigned int reg, unsigned int val)
243 return i2c_smbus_write_byte_data(context, reg + 11, val);
246 static bool max1668_regmap_is_volatile(struct device *dev, unsigned int reg)
248 return reg <= MAX1668_REG_STAT2;
251 static bool max1668_regmap_is_writeable(struct device *dev, unsigned int reg)
253 return reg > MAX1668_REG_STAT2 && reg <= MAX1668_REG_LIML(4);
256 static const struct regmap_config max1668_regmap_config = {
259 .cache_type = REGCACHE_MAPLE,
260 .volatile_reg = max1668_regmap_is_volatile,
261 .writeable_reg = max1668_regmap_is_writeable,
264 static const struct regmap_bus max1668_regmap_bus = {
265 .reg_write = max1668_reg_write,
266 .reg_read = max1668_reg_read,
269 static int max1668_probe(struct i2c_client *client)
271 struct i2c_adapter *adapter = client->adapter;
272 struct device *dev = &client->dev;
273 struct device *hwmon_dev;
274 struct max1668_data *data;
276 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
279 data = devm_kzalloc(dev, sizeof(struct max1668_data), GFP_KERNEL);
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);
288 data->channels = (uintptr_t)i2c_get_match_data(client);
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);
295 static const struct i2c_device_id max1668_id[] = {
301 MODULE_DEVICE_TABLE(i2c, max1668_id);
303 /* This is the driver that will be inserted */
304 static struct i2c_driver max1668_driver = {
305 .class = I2C_CLASS_HWMON,
309 .probe = max1668_probe,
310 .id_table = max1668_id,
311 .detect = max1668_detect,
312 .address_list = max1668_addr_list,
315 module_i2c_driver(max1668_driver);
317 MODULE_AUTHOR("David George <david.george@ska.ac.za>");
318 MODULE_DESCRIPTION("MAX1668 remote temperature sensor driver");
319 MODULE_LICENSE("GPL");