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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (c) 2011 David George <david.george@ska.ac.za>4 *5 * based on adm1021.c6 * some credit to Christoph Scheurer, but largely a rewrite7 */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 0x0527#define MAX1668_REG_STAT2 0x0628#define MAX1668_REG_MAN_ID 0xfe29#define MAX1668_REG_DEV_ID 0xff30 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 0x4d40#define DEV_ID_MAX1668 0x341#define DEV_ID_MAX1805 0x542#define DEV_ID_MAX1989 0xb43 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 else92 *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 else103 *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 NULL178};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");320