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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * lm92 - Hardware monitoring driver4 * Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>5 *6 * Based on the lm90 driver, with some ideas taken from the lm_sensors7 * lm92 driver as well.8 *9 * The LM92 is a sensor chip made by National Semiconductor. It reports10 * its own temperature with a 0.0625 deg resolution and a 0.33 deg11 * accuracy. Complete datasheet can be obtained from National's website12 * at:13 * http://www.national.com/pf/LM/LM92.html14 *15 * This driver also supports the MAX6635 sensor chip made by Maxim.16 * This chip is compatible with the LM92, but has a lesser accuracy17 * (1.0 deg). Complete datasheet can be obtained from Maxim's website18 * at:19 * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/307420 *21 * Since the LM92 was the first chipset supported by this driver, most22 * comments will refer to this chipset, but are actually general and23 * concern all supported chipsets, unless mentioned otherwise.24 *25 * Support could easily be added for the National Semiconductor LM7626 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible27 * with the LM92.28 */29 30#include <linux/err.h>31#include <linux/hwmon.h>32#include <linux/i2c.h>33#include <linux/init.h>34#include <linux/module.h>35#include <linux/mutex.h>36#include <linux/regmap.h>37#include <linux/slab.h>38 39/*40 * The LM92 and MAX6635 have 2 two-state pins for address selection,41 * resulting in 4 possible addresses.42 */43static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,44 I2C_CLIENT_END };45/* The LM92 registers */46#define LM92_REG_CONFIG 0x01 /* 8-bit, RW */47#define LM92_REG_TEMP 0x00 /* 16-bit, RO */48#define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */49#define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */50#define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */51#define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */52#define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */53 54/*55 * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,56 * left-justified in 16-bit registers. No rounding is done, with such57 * a resolution it's just not worth it. Note that the MAX6635 doesn't58 * make use of the 4 lower bits for limits (i.e. effective resolution59 * for limits is 1 degree Celsius).60 */61static inline int TEMP_FROM_REG(s16 reg)62{63 return reg / 8 * 625 / 10;64}65 66static inline s16 TEMP_TO_REG(long val, int resolution)67{68 val = clamp_val(val, -60000, 160000);69 return DIV_ROUND_CLOSEST(val << (resolution - 9), 1000) << (16 - resolution);70}71 72/* Alarm flags are stored in the 3 LSB of the temperature register */73static inline u8 ALARMS_FROM_REG(s16 reg)74{75 return reg & 0x0007;76}77 78/* Client data (each client gets its own) */79struct lm92_data {80 struct regmap *regmap;81 struct mutex update_lock;82 int resolution;83};84 85static int lm92_temp_read(struct lm92_data *data, u32 attr, int channel, long *val)86{87 int reg = -1, hyst_reg = -1, alarm_bit = 0;88 struct regmap *regmap = data->regmap;89 u32 temp;90 int ret;91 92 switch (attr) {93 case hwmon_temp_input:94 reg = LM92_REG_TEMP;95 break;96 case hwmon_temp_min:97 reg = LM92_REG_TEMP_LOW;98 break;99 case hwmon_temp_max:100 reg = LM92_REG_TEMP_HIGH;101 break;102 case hwmon_temp_crit:103 reg = LM92_REG_TEMP_CRIT;104 break;105 case hwmon_temp_min_hyst:106 hyst_reg = LM92_REG_TEMP_LOW;107 break;108 case hwmon_temp_max_hyst:109 hyst_reg = LM92_REG_TEMP_HIGH;110 break;111 case hwmon_temp_crit_hyst:112 hyst_reg = LM92_REG_TEMP_CRIT;113 break;114 case hwmon_temp_min_alarm:115 alarm_bit = 0;116 break;117 case hwmon_temp_max_alarm:118 alarm_bit = 1;119 break;120 case hwmon_temp_crit_alarm:121 alarm_bit = 2;122 break;123 default:124 return -EOPNOTSUPP;125 }126 if (reg >= 0) {127 ret = regmap_read(regmap, reg, &temp);128 if (ret < 0)129 return ret;130 *val = TEMP_FROM_REG(temp);131 } else if (hyst_reg >= 0) {132 u32 regs[2] = { hyst_reg, LM92_REG_TEMP_HYST };133 u16 regvals[2];134 135 ret = regmap_multi_reg_read(regmap, regs, regvals, 2);136 if (ret)137 return ret;138 if (attr == hwmon_temp_min_hyst)139 *val = TEMP_FROM_REG(regvals[0]) + TEMP_FROM_REG(regvals[1]);140 else141 *val = TEMP_FROM_REG(regvals[0]) - TEMP_FROM_REG(regvals[1]);142 } else {143 ret = regmap_read(regmap, LM92_REG_TEMP, &temp);144 if (ret)145 return ret;146 *val = !!(temp & BIT(alarm_bit));147 }148 return 0;149}150 151static int lm92_chip_read(struct lm92_data *data, u32 attr, long *val)152{153 u32 temp;154 int ret;155 156 switch (attr) {157 case hwmon_chip_alarms:158 ret = regmap_read(data->regmap, LM92_REG_TEMP, &temp);159 if (ret)160 return ret;161 *val = ALARMS_FROM_REG(temp);162 break;163 default:164 return -EOPNOTSUPP;165 }166 return 0;167}168 169static int lm92_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,170 int channel, long *val)171{172 struct lm92_data *data = dev_get_drvdata(dev);173 174 switch (type) {175 case hwmon_chip:176 return lm92_chip_read(data, attr, val);177 case hwmon_temp:178 return lm92_temp_read(data, attr, channel, val);179 default:180 return -EOPNOTSUPP;181 }182}183 184static int lm92_temp_write(struct lm92_data *data, u32 attr, long val)185{186 struct regmap *regmap = data->regmap;187 int reg, err;188 u32 temp;189 190 switch (attr) {191 case hwmon_temp_min:192 reg = LM92_REG_TEMP_LOW;193 break;194 case hwmon_temp_max:195 reg = LM92_REG_TEMP_HIGH;196 break;197 case hwmon_temp_crit:198 reg = LM92_REG_TEMP_CRIT;199 break;200 case hwmon_temp_crit_hyst:201 val = clamp_val(val, -120000, 220000);202 mutex_lock(&data->update_lock);203 err = regmap_read(regmap, LM92_REG_TEMP_CRIT, &temp);204 if (err)205 goto unlock;206 val = TEMP_TO_REG(TEMP_FROM_REG(temp) - val, data->resolution);207 err = regmap_write(regmap, LM92_REG_TEMP_HYST, val);208unlock:209 mutex_unlock(&data->update_lock);210 return err;211 default:212 return -EOPNOTSUPP;213 }214 return regmap_write(regmap, reg, TEMP_TO_REG(val, data->resolution));215}216 217static int lm92_write(struct device *dev, enum hwmon_sensor_types type,218 u32 attr, int channel, long val)219{220 struct lm92_data *data = dev_get_drvdata(dev);221 222 switch (type) {223 case hwmon_temp:224 return lm92_temp_write(data, attr, val);225 default:226 return -EOPNOTSUPP;227 }228}229 230static umode_t lm92_is_visible(const void *_data, enum hwmon_sensor_types type,231 u32 attr, int channel)232{233 switch (type) {234 case hwmon_chip:235 switch (attr) {236 case hwmon_chip_alarms:237 return 0444;238 default:239 break;240 }241 break;242 case hwmon_temp:243 switch (attr) {244 case hwmon_temp_min:245 case hwmon_temp_max:246 case hwmon_temp_crit:247 case hwmon_temp_crit_hyst:248 return 0644;249 case hwmon_temp_input:250 case hwmon_temp_min_hyst:251 case hwmon_temp_max_hyst:252 case hwmon_temp_min_alarm:253 case hwmon_temp_max_alarm:254 case hwmon_temp_crit_alarm:255 return 0444;256 default:257 break;258 }259 break;260 default:261 break;262 }263 return 0;264}265 266static const struct hwmon_channel_info * const lm92_info[] = {267 HWMON_CHANNEL_INFO(chip, HWMON_C_ALARMS),268 HWMON_CHANNEL_INFO(temp,269 HWMON_T_INPUT |270 HWMON_T_MIN | HWMON_T_MIN_HYST |271 HWMON_T_MAX | HWMON_T_MAX_HYST |272 HWMON_T_CRIT | HWMON_T_CRIT_HYST |273 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |274 HWMON_T_CRIT_ALARM),275 NULL276};277 278static const struct hwmon_ops lm92_hwmon_ops = {279 .is_visible = lm92_is_visible,280 .read = lm92_read,281 .write = lm92_write,282};283 284static const struct hwmon_chip_info lm92_chip_info = {285 .ops = &lm92_hwmon_ops,286 .info = lm92_info,287};288 289/*290 * Detection and registration291 */292 293static int lm92_init_client(struct regmap *regmap)294{295 return regmap_clear_bits(regmap, LM92_REG_CONFIG, 0x01);296}297 298/* Return 0 if detection is successful, -ENODEV otherwise */299static int lm92_detect(struct i2c_client *new_client,300 struct i2c_board_info *info)301{302 struct i2c_adapter *adapter = new_client->adapter;303 u8 config_addr = LM92_REG_CONFIG;304 u8 man_id_addr = LM92_REG_MAN_ID;305 int i, regval;306 307 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA308 | I2C_FUNC_SMBUS_WORD_DATA))309 return -ENODEV;310 311 /*312 * Register values repeat with multiples of 8.313 * Read twice to improve detection accuracy.314 */315 for (i = 0; i < 2; i++) {316 regval = i2c_smbus_read_word_data(new_client, man_id_addr);317 if (regval != 0x0180)318 return -ENODEV;319 regval = i2c_smbus_read_byte_data(new_client, config_addr);320 if (regval < 0 || (regval & 0xe0))321 return -ENODEV;322 config_addr += 8;323 man_id_addr += 8;324 }325 326 strscpy(info->type, "lm92", I2C_NAME_SIZE);327 328 return 0;329}330 331/* regmap */332 333static int lm92_reg_read(void *context, unsigned int reg, unsigned int *val)334{335 int ret;336 337 if (reg == LM92_REG_CONFIG)338 ret = i2c_smbus_read_byte_data(context, reg);339 else340 ret = i2c_smbus_read_word_swapped(context, reg);341 if (ret < 0)342 return ret;343 344 *val = ret;345 return 0;346}347 348static int lm92_reg_write(void *context, unsigned int reg, unsigned int val)349{350 if (reg == LM92_REG_CONFIG)351 return i2c_smbus_write_byte_data(context, LM92_REG_CONFIG, val);352 353 return i2c_smbus_write_word_swapped(context, reg, val);354}355 356static bool lm92_regmap_is_volatile(struct device *dev, unsigned int reg)357{358 return reg == LM92_REG_TEMP;359}360 361static bool lm92_regmap_is_writeable(struct device *dev, unsigned int reg)362{363 return reg >= LM92_REG_CONFIG;364}365 366static const struct regmap_config lm92_regmap_config = {367 .reg_bits = 8,368 .val_bits = 16,369 .max_register = LM92_REG_TEMP_HIGH,370 .cache_type = REGCACHE_MAPLE,371 .volatile_reg = lm92_regmap_is_volatile,372 .writeable_reg = lm92_regmap_is_writeable,373};374 375static const struct regmap_bus lm92_regmap_bus = {376 .reg_write = lm92_reg_write,377 .reg_read = lm92_reg_read,378};379 380static int lm92_probe(struct i2c_client *client)381{382 struct device *dev = &client->dev;383 struct device *hwmon_dev;384 struct lm92_data *data;385 struct regmap *regmap;386 int err;387 388 regmap = devm_regmap_init(dev, &lm92_regmap_bus, client,389 &lm92_regmap_config);390 if (IS_ERR(regmap))391 return PTR_ERR(regmap);392 393 data = devm_kzalloc(dev, sizeof(struct lm92_data), GFP_KERNEL);394 if (!data)395 return -ENOMEM;396 397 data->regmap = regmap;398 data->resolution = (unsigned long)i2c_get_match_data(client);399 mutex_init(&data->update_lock);400 401 /* Initialize the chipset */402 err = lm92_init_client(regmap);403 if (err)404 return err;405 406 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,407 &lm92_chip_info, NULL);408 return PTR_ERR_OR_ZERO(hwmon_dev);409}410 411/*412 * Module and driver stuff413 */414 415/* .driver_data is limit register resolution */ 416static const struct i2c_device_id lm92_id[] = {417 { "lm92", 13 },418 { "max6635", 9 },419 { }420};421MODULE_DEVICE_TABLE(i2c, lm92_id);422 423static struct i2c_driver lm92_driver = {424 .class = I2C_CLASS_HWMON,425 .driver = {426 .name = "lm92",427 },428 .probe = lm92_probe,429 .id_table = lm92_id,430 .detect = lm92_detect,431 .address_list = normal_i2c,432};433 434module_i2c_driver(lm92_driver);435 436MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");437MODULE_DESCRIPTION("LM92/MAX6635 driver");438MODULE_LICENSE("GPL");439