1 /* tmp421.c 2 * 3 * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de> 4 * Preliminary support by: 5 * Melvin Rook, Raymond Ng 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 */ 17 18 /* 19 * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC. 20 * Supported models: TMP421, TMP422, TMP423, TMP441, TMP442 21 */ 22 23 #include <linux/module.h> 24 #include <linux/init.h> 25 #include <linux/slab.h> 26 #include <linux/jiffies.h> 27 #include <linux/i2c.h> 28 #include <linux/hwmon.h> 29 #include <linux/hwmon-sysfs.h> 30 #include <linux/err.h> 31 #include <linux/mutex.h> 32 #include <linux/sysfs.h> 33 34 /* Addresses to scan */ 35 static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f, 36 I2C_CLIENT_END }; 37 38 enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 }; 39 40 /* The TMP421 registers */ 41 #define TMP421_STATUS_REG 0x08 42 #define TMP421_CONFIG_REG_1 0x09 43 #define TMP421_CONVERSION_RATE_REG 0x0B 44 #define TMP421_MANUFACTURER_ID_REG 0xFE 45 #define TMP421_DEVICE_ID_REG 0xFF 46 47 static const u8 TMP421_TEMP_MSB[4] = { 0x00, 0x01, 0x02, 0x03 }; 48 static const u8 TMP421_TEMP_LSB[4] = { 0x10, 0x11, 0x12, 0x13 }; 49 50 /* Flags */ 51 #define TMP421_CONFIG_SHUTDOWN 0x40 52 #define TMP421_CONFIG_RANGE 0x04 53 54 /* Manufacturer / Device ID's */ 55 #define TMP421_MANUFACTURER_ID 0x55 56 #define TMP421_DEVICE_ID 0x21 57 #define TMP422_DEVICE_ID 0x22 58 #define TMP423_DEVICE_ID 0x23 59 #define TMP441_DEVICE_ID 0x41 60 #define TMP442_DEVICE_ID 0x42 61 62 static const struct i2c_device_id tmp421_id[] = { 63 { "tmp421", 2 }, 64 { "tmp422", 3 }, 65 { "tmp423", 4 }, 66 { "tmp441", 2 }, 67 { "tmp442", 3 }, 68 { } 69 }; 70 MODULE_DEVICE_TABLE(i2c, tmp421_id); 71 72 struct tmp421_data { 73 struct i2c_client *client; 74 struct mutex update_lock; 75 u32 temp_config[5]; 76 struct hwmon_channel_info temp_info; 77 const struct hwmon_channel_info *info[2]; 78 struct hwmon_chip_info chip; 79 char valid; 80 unsigned long last_updated; 81 int channels; 82 u8 config; 83 s16 temp[4]; 84 }; 85 86 static int temp_from_s16(s16 reg) 87 { 88 /* Mask out status bits */ 89 int temp = reg & ~0xf; 90 91 return (temp * 1000 + 128) / 256; 92 } 93 94 static int temp_from_u16(u16 reg) 95 { 96 /* Mask out status bits */ 97 int temp = reg & ~0xf; 98 99 /* Add offset for extended temperature range. */ 100 temp -= 64 * 256; 101 102 return (temp * 1000 + 128) / 256; 103 } 104 105 static struct tmp421_data *tmp421_update_device(struct device *dev) 106 { 107 struct tmp421_data *data = dev_get_drvdata(dev); 108 struct i2c_client *client = data->client; 109 int i; 110 111 mutex_lock(&data->update_lock); 112 113 if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) { 114 data->config = i2c_smbus_read_byte_data(client, 115 TMP421_CONFIG_REG_1); 116 117 for (i = 0; i < data->channels; i++) { 118 data->temp[i] = i2c_smbus_read_byte_data(client, 119 TMP421_TEMP_MSB[i]) << 8; 120 data->temp[i] |= i2c_smbus_read_byte_data(client, 121 TMP421_TEMP_LSB[i]); 122 } 123 data->last_updated = jiffies; 124 data->valid = 1; 125 } 126 127 mutex_unlock(&data->update_lock); 128 129 return data; 130 } 131 132 static int tmp421_read(struct device *dev, enum hwmon_sensor_types type, 133 u32 attr, int channel, long *val) 134 { 135 struct tmp421_data *tmp421 = tmp421_update_device(dev); 136 137 switch (attr) { 138 case hwmon_temp_input: 139 if (tmp421->config & TMP421_CONFIG_RANGE) 140 *val = temp_from_u16(tmp421->temp[channel]); 141 else 142 *val = temp_from_s16(tmp421->temp[channel]); 143 return 0; 144 case hwmon_temp_fault: 145 /* 146 * The OPEN bit signals a fault. This is bit 0 of the temperature 147 * register (low byte). 148 */ 149 *val = tmp421->temp[channel] & 0x01; 150 return 0; 151 default: 152 return -EOPNOTSUPP; 153 } 154 155 } 156 157 static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type, 158 u32 attr, int channel) 159 { 160 switch (attr) { 161 case hwmon_temp_fault: 162 if (channel == 0) 163 return 0; 164 return S_IRUGO; 165 case hwmon_temp_input: 166 return S_IRUGO; 167 default: 168 return 0; 169 } 170 } 171 172 static int tmp421_init_client(struct i2c_client *client) 173 { 174 int config, config_orig; 175 176 /* Set the conversion rate to 2 Hz */ 177 i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05); 178 179 /* Start conversions (disable shutdown if necessary) */ 180 config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1); 181 if (config < 0) { 182 dev_err(&client->dev, 183 "Could not read configuration register (%d)\n", config); 184 return config; 185 } 186 187 config_orig = config; 188 config &= ~TMP421_CONFIG_SHUTDOWN; 189 190 if (config != config_orig) { 191 dev_info(&client->dev, "Enable monitoring chip\n"); 192 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config); 193 } 194 195 return 0; 196 } 197 198 static int tmp421_detect(struct i2c_client *client, 199 struct i2c_board_info *info) 200 { 201 enum chips kind; 202 struct i2c_adapter *adapter = client->adapter; 203 const char * const names[] = { "TMP421", "TMP422", "TMP423", 204 "TMP441", "TMP442" }; 205 int addr = client->addr; 206 u8 reg; 207 208 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 209 return -ENODEV; 210 211 reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG); 212 if (reg != TMP421_MANUFACTURER_ID) 213 return -ENODEV; 214 215 reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG); 216 if (reg & 0xf8) 217 return -ENODEV; 218 219 reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG); 220 if (reg & 0x7f) 221 return -ENODEV; 222 223 reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG); 224 switch (reg) { 225 case TMP421_DEVICE_ID: 226 kind = tmp421; 227 break; 228 case TMP422_DEVICE_ID: 229 if (addr == 0x2a) 230 return -ENODEV; 231 kind = tmp422; 232 break; 233 case TMP423_DEVICE_ID: 234 if (addr != 0x4c && addr != 0x4d) 235 return -ENODEV; 236 kind = tmp423; 237 break; 238 case TMP441_DEVICE_ID: 239 kind = tmp441; 240 break; 241 case TMP442_DEVICE_ID: 242 if (addr != 0x4c && addr != 0x4d) 243 return -ENODEV; 244 kind = tmp442; 245 break; 246 default: 247 return -ENODEV; 248 } 249 250 strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE); 251 dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n", 252 names[kind], client->addr); 253 254 return 0; 255 } 256 257 static const struct hwmon_ops tmp421_ops = { 258 .is_visible = tmp421_is_visible, 259 .read = tmp421_read, 260 }; 261 262 static int tmp421_probe(struct i2c_client *client, 263 const struct i2c_device_id *id) 264 { 265 struct device *dev = &client->dev; 266 struct device *hwmon_dev; 267 struct tmp421_data *data; 268 int i, err; 269 270 data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL); 271 if (!data) 272 return -ENOMEM; 273 274 mutex_init(&data->update_lock); 275 data->channels = id->driver_data; 276 data->client = client; 277 278 err = tmp421_init_client(client); 279 if (err) 280 return err; 281 282 for (i = 0; i < data->channels; i++) 283 data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT; 284 285 data->chip.ops = &tmp421_ops; 286 data->chip.info = data->info; 287 288 data->info[0] = &data->temp_info; 289 290 data->temp_info.type = hwmon_temp; 291 data->temp_info.config = data->temp_config; 292 293 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, 294 data, 295 &data->chip, 296 NULL); 297 return PTR_ERR_OR_ZERO(hwmon_dev); 298 } 299 300 static struct i2c_driver tmp421_driver = { 301 .class = I2C_CLASS_HWMON, 302 .driver = { 303 .name = "tmp421", 304 }, 305 .probe = tmp421_probe, 306 .id_table = tmp421_id, 307 .detect = tmp421_detect, 308 .address_list = normal_i2c, 309 }; 310 311 module_i2c_driver(tmp421_driver); 312 313 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>"); 314 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver"); 315 MODULE_LICENSE("GPL"); 316