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 + (HZ / 2)) || 131 !data->valid) { 132 data->config = i2c_smbus_read_byte_data(client, 133 TMP421_CONFIG_REG_1); 134 135 for (i = 0; i < data->channels; i++) { 136 data->temp[i] = i2c_smbus_read_byte_data(client, 137 TMP421_TEMP_MSB[i]) << 8; 138 data->temp[i] |= i2c_smbus_read_byte_data(client, 139 TMP421_TEMP_LSB[i]); 140 } 141 data->last_updated = jiffies; 142 data->valid = 1; 143 } 144 145 mutex_unlock(&data->update_lock); 146 147 return data; 148 } 149 150 static int tmp421_read(struct device *dev, enum hwmon_sensor_types type, 151 u32 attr, int channel, long *val) 152 { 153 struct tmp421_data *tmp421 = tmp421_update_device(dev); 154 155 switch (attr) { 156 case hwmon_temp_input: 157 if (tmp421->config & TMP421_CONFIG_RANGE) 158 *val = temp_from_u16(tmp421->temp[channel]); 159 else 160 *val = temp_from_s16(tmp421->temp[channel]); 161 return 0; 162 case hwmon_temp_fault: 163 /* 164 * The OPEN bit signals a fault. This is bit 0 of the temperature 165 * register (low byte). 166 */ 167 *val = tmp421->temp[channel] & 0x01; 168 return 0; 169 default: 170 return -EOPNOTSUPP; 171 } 172 173 } 174 175 static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type, 176 u32 attr, int channel) 177 { 178 switch (attr) { 179 case hwmon_temp_fault: 180 if (channel == 0) 181 return 0; 182 return 0444; 183 case hwmon_temp_input: 184 return 0444; 185 default: 186 return 0; 187 } 188 } 189 190 static int tmp421_init_client(struct i2c_client *client) 191 { 192 int config, config_orig; 193 194 /* Set the conversion rate to 2 Hz */ 195 i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05); 196 197 /* Start conversions (disable shutdown if necessary) */ 198 config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1); 199 if (config < 0) { 200 dev_err(&client->dev, 201 "Could not read configuration register (%d)\n", config); 202 return config; 203 } 204 205 config_orig = config; 206 config &= ~TMP421_CONFIG_SHUTDOWN; 207 208 if (config != config_orig) { 209 dev_info(&client->dev, "Enable monitoring chip\n"); 210 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config); 211 } 212 213 return 0; 214 } 215 216 static int tmp421_detect(struct i2c_client *client, 217 struct i2c_board_info *info) 218 { 219 enum chips kind; 220 struct i2c_adapter *adapter = client->adapter; 221 static const char * const names[] = { 222 "TMP421", "TMP422", "TMP423", 223 "TMP441", "TMP442" 224 }; 225 int addr = client->addr; 226 u8 reg; 227 228 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 229 return -ENODEV; 230 231 reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG); 232 if (reg != TMP421_MANUFACTURER_ID) 233 return -ENODEV; 234 235 reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG); 236 if (reg & 0xf8) 237 return -ENODEV; 238 239 reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG); 240 if (reg & 0x7f) 241 return -ENODEV; 242 243 reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG); 244 switch (reg) { 245 case TMP421_DEVICE_ID: 246 kind = tmp421; 247 break; 248 case TMP422_DEVICE_ID: 249 if (addr == 0x2a) 250 return -ENODEV; 251 kind = tmp422; 252 break; 253 case TMP423_DEVICE_ID: 254 if (addr != 0x4c && addr != 0x4d) 255 return -ENODEV; 256 kind = tmp423; 257 break; 258 case TMP441_DEVICE_ID: 259 kind = tmp441; 260 break; 261 case TMP442_DEVICE_ID: 262 if (addr != 0x4c && addr != 0x4d) 263 return -ENODEV; 264 kind = tmp442; 265 break; 266 default: 267 return -ENODEV; 268 } 269 270 strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE); 271 dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n", 272 names[kind], client->addr); 273 274 return 0; 275 } 276 277 static const struct hwmon_ops tmp421_ops = { 278 .is_visible = tmp421_is_visible, 279 .read = tmp421_read, 280 }; 281 282 static int tmp421_probe(struct i2c_client *client, 283 const struct i2c_device_id *id) 284 { 285 struct device *dev = &client->dev; 286 struct device *hwmon_dev; 287 struct tmp421_data *data; 288 int i, err; 289 290 data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL); 291 if (!data) 292 return -ENOMEM; 293 294 mutex_init(&data->update_lock); 295 if (client->dev.of_node) 296 data->channels = (unsigned long) 297 of_device_get_match_data(&client->dev); 298 else 299 data->channels = id->driver_data; 300 data->client = client; 301 302 err = tmp421_init_client(client); 303 if (err) 304 return err; 305 306 for (i = 0; i < data->channels; i++) 307 data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT; 308 309 data->chip.ops = &tmp421_ops; 310 data->chip.info = data->info; 311 312 data->info[0] = &data->temp_info; 313 314 data->temp_info.type = hwmon_temp; 315 data->temp_info.config = data->temp_config; 316 317 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, 318 data, 319 &data->chip, 320 NULL); 321 return PTR_ERR_OR_ZERO(hwmon_dev); 322 } 323 324 static struct i2c_driver tmp421_driver = { 325 .class = I2C_CLASS_HWMON, 326 .driver = { 327 .name = "tmp421", 328 .of_match_table = of_match_ptr(tmp421_of_match), 329 }, 330 .probe = tmp421_probe, 331 .id_table = tmp421_id, 332 .detect = tmp421_detect, 333 .address_list = normal_i2c, 334 }; 335 336 module_i2c_driver(tmp421_driver); 337 338 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>"); 339 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver"); 340 MODULE_LICENSE("GPL"); 341