1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* tmp421.c 3 * 4 * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de> 5 * Preliminary support by: 6 * Melvin Rook, Raymond Ng 7 */ 8 9 /* 10 * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC. 11 * Supported models: TMP421, TMP422, TMP423, TMP441, TMP442 12 */ 13 14 #include <linux/module.h> 15 #include <linux/init.h> 16 #include <linux/slab.h> 17 #include <linux/jiffies.h> 18 #include <linux/i2c.h> 19 #include <linux/hwmon.h> 20 #include <linux/hwmon-sysfs.h> 21 #include <linux/err.h> 22 #include <linux/mutex.h> 23 #include <linux/of_device.h> 24 #include <linux/sysfs.h> 25 26 /* Addresses to scan */ 27 static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f, 28 I2C_CLIENT_END }; 29 30 enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 }; 31 32 /* The TMP421 registers */ 33 #define TMP421_STATUS_REG 0x08 34 #define TMP421_CONFIG_REG_1 0x09 35 #define TMP421_CONVERSION_RATE_REG 0x0B 36 #define TMP421_MANUFACTURER_ID_REG 0xFE 37 #define TMP421_DEVICE_ID_REG 0xFF 38 39 static const u8 TMP421_TEMP_MSB[4] = { 0x00, 0x01, 0x02, 0x03 }; 40 static const u8 TMP421_TEMP_LSB[4] = { 0x10, 0x11, 0x12, 0x13 }; 41 42 /* Flags */ 43 #define TMP421_CONFIG_SHUTDOWN 0x40 44 #define TMP421_CONFIG_RANGE 0x04 45 46 /* Manufacturer / Device ID's */ 47 #define TMP421_MANUFACTURER_ID 0x55 48 #define TMP421_DEVICE_ID 0x21 49 #define TMP422_DEVICE_ID 0x22 50 #define TMP423_DEVICE_ID 0x23 51 #define TMP441_DEVICE_ID 0x41 52 #define TMP442_DEVICE_ID 0x42 53 54 static const struct i2c_device_id tmp421_id[] = { 55 { "tmp421", 2 }, 56 { "tmp422", 3 }, 57 { "tmp423", 4 }, 58 { "tmp441", 2 }, 59 { "tmp442", 3 }, 60 { } 61 }; 62 MODULE_DEVICE_TABLE(i2c, tmp421_id); 63 64 static const struct of_device_id __maybe_unused tmp421_of_match[] = { 65 { 66 .compatible = "ti,tmp421", 67 .data = (void *)2 68 }, 69 { 70 .compatible = "ti,tmp422", 71 .data = (void *)3 72 }, 73 { 74 .compatible = "ti,tmp423", 75 .data = (void *)4 76 }, 77 { 78 .compatible = "ti,tmp441", 79 .data = (void *)2 80 }, 81 { 82 .compatible = "ti,tmp442", 83 .data = (void *)3 84 }, 85 { }, 86 }; 87 MODULE_DEVICE_TABLE(of, tmp421_of_match); 88 89 struct tmp421_data { 90 struct i2c_client *client; 91 struct mutex update_lock; 92 u32 temp_config[5]; 93 struct hwmon_channel_info temp_info; 94 const struct hwmon_channel_info *info[2]; 95 struct hwmon_chip_info chip; 96 char valid; 97 unsigned long last_updated; 98 unsigned long channels; 99 u8 config; 100 s16 temp[4]; 101 }; 102 103 static int temp_from_s16(s16 reg) 104 { 105 /* Mask out status bits */ 106 int temp = reg & ~0xf; 107 108 return (temp * 1000 + 128) / 256; 109 } 110 111 static int temp_from_u16(u16 reg) 112 { 113 /* Mask out status bits */ 114 int temp = reg & ~0xf; 115 116 /* Add offset for extended temperature range. */ 117 temp -= 64 * 256; 118 119 return (temp * 1000 + 128) / 256; 120 } 121 122 static struct tmp421_data *tmp421_update_device(struct device *dev) 123 { 124 struct tmp421_data *data = dev_get_drvdata(dev); 125 struct i2c_client *client = data->client; 126 int i; 127 128 mutex_lock(&data->update_lock); 129 130 if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) { 131 data->config = i2c_smbus_read_byte_data(client, 132 TMP421_CONFIG_REG_1); 133 134 for (i = 0; i < data->channels; i++) { 135 data->temp[i] = i2c_smbus_read_byte_data(client, 136 TMP421_TEMP_MSB[i]) << 8; 137 data->temp[i] |= i2c_smbus_read_byte_data(client, 138 TMP421_TEMP_LSB[i]); 139 } 140 data->last_updated = jiffies; 141 data->valid = 1; 142 } 143 144 mutex_unlock(&data->update_lock); 145 146 return data; 147 } 148 149 static int tmp421_read(struct device *dev, enum hwmon_sensor_types type, 150 u32 attr, int channel, long *val) 151 { 152 struct tmp421_data *tmp421 = tmp421_update_device(dev); 153 154 switch (attr) { 155 case hwmon_temp_input: 156 if (tmp421->config & TMP421_CONFIG_RANGE) 157 *val = temp_from_u16(tmp421->temp[channel]); 158 else 159 *val = temp_from_s16(tmp421->temp[channel]); 160 return 0; 161 case hwmon_temp_fault: 162 /* 163 * The OPEN bit signals a fault. This is bit 0 of the temperature 164 * register (low byte). 165 */ 166 *val = tmp421->temp[channel] & 0x01; 167 return 0; 168 default: 169 return -EOPNOTSUPP; 170 } 171 172 } 173 174 static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type, 175 u32 attr, int channel) 176 { 177 switch (attr) { 178 case hwmon_temp_fault: 179 if (channel == 0) 180 return 0; 181 return 0444; 182 case hwmon_temp_input: 183 return 0444; 184 default: 185 return 0; 186 } 187 } 188 189 static int tmp421_init_client(struct i2c_client *client) 190 { 191 int config, config_orig; 192 193 /* Set the conversion rate to 2 Hz */ 194 i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05); 195 196 /* Start conversions (disable shutdown if necessary) */ 197 config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1); 198 if (config < 0) { 199 dev_err(&client->dev, 200 "Could not read configuration register (%d)\n", config); 201 return config; 202 } 203 204 config_orig = config; 205 config &= ~TMP421_CONFIG_SHUTDOWN; 206 207 if (config != config_orig) { 208 dev_info(&client->dev, "Enable monitoring chip\n"); 209 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config); 210 } 211 212 return 0; 213 } 214 215 static int tmp421_detect(struct i2c_client *client, 216 struct i2c_board_info *info) 217 { 218 enum chips kind; 219 struct i2c_adapter *adapter = client->adapter; 220 static const char * const names[] = { 221 "TMP421", "TMP422", "TMP423", 222 "TMP441", "TMP442" 223 }; 224 int addr = client->addr; 225 u8 reg; 226 227 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 228 return -ENODEV; 229 230 reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG); 231 if (reg != TMP421_MANUFACTURER_ID) 232 return -ENODEV; 233 234 reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG); 235 if (reg & 0xf8) 236 return -ENODEV; 237 238 reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG); 239 if (reg & 0x7f) 240 return -ENODEV; 241 242 reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG); 243 switch (reg) { 244 case TMP421_DEVICE_ID: 245 kind = tmp421; 246 break; 247 case TMP422_DEVICE_ID: 248 if (addr == 0x2a) 249 return -ENODEV; 250 kind = tmp422; 251 break; 252 case TMP423_DEVICE_ID: 253 if (addr != 0x4c && addr != 0x4d) 254 return -ENODEV; 255 kind = tmp423; 256 break; 257 case TMP441_DEVICE_ID: 258 kind = tmp441; 259 break; 260 case TMP442_DEVICE_ID: 261 if (addr != 0x4c && addr != 0x4d) 262 return -ENODEV; 263 kind = tmp442; 264 break; 265 default: 266 return -ENODEV; 267 } 268 269 strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE); 270 dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n", 271 names[kind], client->addr); 272 273 return 0; 274 } 275 276 static const struct hwmon_ops tmp421_ops = { 277 .is_visible = tmp421_is_visible, 278 .read = tmp421_read, 279 }; 280 281 static int tmp421_probe(struct i2c_client *client, 282 const struct i2c_device_id *id) 283 { 284 struct device *dev = &client->dev; 285 struct device *hwmon_dev; 286 struct tmp421_data *data; 287 int i, err; 288 289 data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL); 290 if (!data) 291 return -ENOMEM; 292 293 mutex_init(&data->update_lock); 294 if (client->dev.of_node) 295 data->channels = (unsigned long) 296 of_device_get_match_data(&client->dev); 297 else 298 data->channels = id->driver_data; 299 data->client = client; 300 301 err = tmp421_init_client(client); 302 if (err) 303 return err; 304 305 for (i = 0; i < data->channels; i++) 306 data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT; 307 308 data->chip.ops = &tmp421_ops; 309 data->chip.info = data->info; 310 311 data->info[0] = &data->temp_info; 312 313 data->temp_info.type = hwmon_temp; 314 data->temp_info.config = data->temp_config; 315 316 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, 317 data, 318 &data->chip, 319 NULL); 320 return PTR_ERR_OR_ZERO(hwmon_dev); 321 } 322 323 static struct i2c_driver tmp421_driver = { 324 .class = I2C_CLASS_HWMON, 325 .driver = { 326 .name = "tmp421", 327 .of_match_table = of_match_ptr(tmp421_of_match), 328 }, 329 .probe = tmp421_probe, 330 .id_table = tmp421_id, 331 .detect = tmp421_detect, 332 .address_list = normal_i2c, 333 }; 334 335 module_i2c_driver(tmp421_driver); 336 337 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>"); 338 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver"); 339 MODULE_LICENSE("GPL"); 340