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 */ 20 static 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 */ 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"); 48 49 struct max1668_data { 50 struct regmap *regmap; 51 int channels; 52 }; 53 54 static 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 } 116 117 static 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 } 134 135 static 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 } 160 161 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 | 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 }; 179 180 static const struct hwmon_ops max1668_hwmon_ops = { 181 .is_visible = max1668_is_visible, 182 .read = max1668_read, 183 .write = max1668_write, 184 }; 185 186 static 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 */ 192 static 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 */ 228 229 static 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 } 240 241 static 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 } 245 246 static bool max1668_regmap_is_volatile(struct device *dev, unsigned int reg) 247 { 248 return reg <= MAX1668_REG_STAT2; 249 } 250 251 static bool max1668_regmap_is_writeable(struct device *dev, unsigned int reg) 252 { 253 return reg > MAX1668_REG_STAT2 && reg <= MAX1668_REG_LIML(4); 254 } 255 256 static 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 }; 263 264 static const struct regmap_bus max1668_regmap_bus = { 265 .reg_write = max1668_reg_write, 266 .reg_read = max1668_reg_read, 267 }; 268 269 static 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 } 294 295 static const struct i2c_device_id max1668_id[] = { 296 { "max1668", 5 }, 297 { "max1805", 3 }, 298 { "max1989", 5 }, 299 { } 300 }; 301 MODULE_DEVICE_TABLE(i2c, max1668_id); 302 303 /* This is the driver that will be inserted */ 304 static 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 }; 314 315 module_i2c_driver(max1668_driver); 316 317 MODULE_AUTHOR("David George <david.george@ska.ac.za>"); 318 MODULE_DESCRIPTION("MAX1668 remote temperature sensor driver"); 319 MODULE_LICENSE("GPL"); 320