1 /* 2 lm75.c - Part of lm_sensors, Linux kernel modules for hardware 3 monitoring 4 Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl> 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program; if not, write to the Free Software 18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 19 */ 20 21 #include <linux/module.h> 22 #include <linux/init.h> 23 #include <linux/slab.h> 24 #include <linux/jiffies.h> 25 #include <linux/i2c.h> 26 #include <linux/hwmon.h> 27 #include <linux/hwmon-sysfs.h> 28 #include <linux/err.h> 29 #include <linux/mutex.h> 30 #include "lm75.h" 31 32 33 /* Addresses to scan */ 34 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, 35 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; 36 37 /* Insmod parameters */ 38 I2C_CLIENT_INSMOD_1(lm75); 39 40 /* Many LM75 constants specified below */ 41 42 /* The LM75 registers */ 43 #define LM75_REG_CONF 0x01 44 static const u8 LM75_REG_TEMP[3] = { 45 0x00, /* input */ 46 0x03, /* max */ 47 0x02, /* hyst */ 48 }; 49 50 /* Each client has this additional data */ 51 struct lm75_data { 52 struct i2c_client client; 53 struct device *hwmon_dev; 54 struct mutex update_lock; 55 char valid; /* !=0 if following fields are valid */ 56 unsigned long last_updated; /* In jiffies */ 57 u16 temp[3]; /* Register values, 58 0 = input 59 1 = max 60 2 = hyst */ 61 }; 62 63 static int lm75_attach_adapter(struct i2c_adapter *adapter); 64 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind); 65 static void lm75_init_client(struct i2c_client *client); 66 static int lm75_detach_client(struct i2c_client *client); 67 static int lm75_read_value(struct i2c_client *client, u8 reg); 68 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value); 69 static struct lm75_data *lm75_update_device(struct device *dev); 70 71 72 /* This is the driver that will be inserted */ 73 static struct i2c_driver lm75_driver = { 74 .driver = { 75 .name = "lm75", 76 }, 77 .attach_adapter = lm75_attach_adapter, 78 .detach_client = lm75_detach_client, 79 }; 80 81 static ssize_t show_temp(struct device *dev, struct device_attribute *da, 82 char *buf) 83 { 84 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 85 struct lm75_data *data = lm75_update_device(dev); 86 return sprintf(buf, "%d\n", 87 LM75_TEMP_FROM_REG(data->temp[attr->index])); 88 } 89 90 static ssize_t set_temp(struct device *dev, struct device_attribute *da, 91 const char *buf, size_t count) 92 { 93 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 94 struct i2c_client *client = to_i2c_client(dev); 95 struct lm75_data *data = i2c_get_clientdata(client); 96 int nr = attr->index; 97 long temp = simple_strtol(buf, NULL, 10); 98 99 mutex_lock(&data->update_lock); 100 data->temp[nr] = LM75_TEMP_TO_REG(temp); 101 lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]); 102 mutex_unlock(&data->update_lock); 103 return count; 104 } 105 106 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 107 show_temp, set_temp, 1); 108 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, 109 show_temp, set_temp, 2); 110 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0); 111 112 static int lm75_attach_adapter(struct i2c_adapter *adapter) 113 { 114 if (!(adapter->class & I2C_CLASS_HWMON)) 115 return 0; 116 return i2c_probe(adapter, &addr_data, lm75_detect); 117 } 118 119 static struct attribute *lm75_attributes[] = { 120 &sensor_dev_attr_temp1_input.dev_attr.attr, 121 &sensor_dev_attr_temp1_max.dev_attr.attr, 122 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, 123 124 NULL 125 }; 126 127 static const struct attribute_group lm75_group = { 128 .attrs = lm75_attributes, 129 }; 130 131 /* This function is called by i2c_probe */ 132 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind) 133 { 134 int i; 135 struct i2c_client *new_client; 136 struct lm75_data *data; 137 int err = 0; 138 const char *name = ""; 139 140 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 141 I2C_FUNC_SMBUS_WORD_DATA)) 142 goto exit; 143 144 /* OK. For now, we presume we have a valid client. We now create the 145 client structure, even though we cannot fill it completely yet. 146 But it allows us to access lm75_{read,write}_value. */ 147 if (!(data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL))) { 148 err = -ENOMEM; 149 goto exit; 150 } 151 152 new_client = &data->client; 153 i2c_set_clientdata(new_client, data); 154 new_client->addr = address; 155 new_client->adapter = adapter; 156 new_client->driver = &lm75_driver; 157 new_client->flags = 0; 158 159 /* Now, we do the remaining detection. There is no identification- 160 dedicated register so we have to rely on several tricks: 161 unused bits, registers cycling over 8-address boundaries, 162 addresses 0x04-0x07 returning the last read value. 163 The cycling+unused addresses combination is not tested, 164 since it would significantly slow the detection down and would 165 hardly add any value. */ 166 if (kind < 0) { 167 int cur, conf, hyst, os; 168 169 /* Unused addresses */ 170 cur = i2c_smbus_read_word_data(new_client, 0); 171 conf = i2c_smbus_read_byte_data(new_client, 1); 172 hyst = i2c_smbus_read_word_data(new_client, 2); 173 if (i2c_smbus_read_word_data(new_client, 4) != hyst 174 || i2c_smbus_read_word_data(new_client, 5) != hyst 175 || i2c_smbus_read_word_data(new_client, 6) != hyst 176 || i2c_smbus_read_word_data(new_client, 7) != hyst) 177 goto exit_free; 178 os = i2c_smbus_read_word_data(new_client, 3); 179 if (i2c_smbus_read_word_data(new_client, 4) != os 180 || i2c_smbus_read_word_data(new_client, 5) != os 181 || i2c_smbus_read_word_data(new_client, 6) != os 182 || i2c_smbus_read_word_data(new_client, 7) != os) 183 goto exit_free; 184 185 /* Unused bits */ 186 if (conf & 0xe0) 187 goto exit_free; 188 189 /* Addresses cycling */ 190 for (i = 8; i < 0xff; i += 8) 191 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 192 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 193 || i2c_smbus_read_word_data(new_client, i + 3) != os) 194 goto exit_free; 195 } 196 197 /* Determine the chip type - only one kind supported! */ 198 if (kind <= 0) 199 kind = lm75; 200 201 if (kind == lm75) { 202 name = "lm75"; 203 } 204 205 /* Fill in the remaining client fields and put it into the global list */ 206 strlcpy(new_client->name, name, I2C_NAME_SIZE); 207 data->valid = 0; 208 mutex_init(&data->update_lock); 209 210 /* Tell the I2C layer a new client has arrived */ 211 if ((err = i2c_attach_client(new_client))) 212 goto exit_free; 213 214 /* Initialize the LM75 chip */ 215 lm75_init_client(new_client); 216 217 /* Register sysfs hooks */ 218 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm75_group))) 219 goto exit_detach; 220 221 data->hwmon_dev = hwmon_device_register(&new_client->dev); 222 if (IS_ERR(data->hwmon_dev)) { 223 err = PTR_ERR(data->hwmon_dev); 224 goto exit_remove; 225 } 226 227 return 0; 228 229 exit_remove: 230 sysfs_remove_group(&new_client->dev.kobj, &lm75_group); 231 exit_detach: 232 i2c_detach_client(new_client); 233 exit_free: 234 kfree(data); 235 exit: 236 return err; 237 } 238 239 static int lm75_detach_client(struct i2c_client *client) 240 { 241 struct lm75_data *data = i2c_get_clientdata(client); 242 hwmon_device_unregister(data->hwmon_dev); 243 sysfs_remove_group(&client->dev.kobj, &lm75_group); 244 i2c_detach_client(client); 245 kfree(data); 246 return 0; 247 } 248 249 /* All registers are word-sized, except for the configuration register. 250 LM75 uses a high-byte first convention, which is exactly opposite to 251 the SMBus standard. */ 252 static int lm75_read_value(struct i2c_client *client, u8 reg) 253 { 254 int value; 255 256 if (reg == LM75_REG_CONF) 257 return i2c_smbus_read_byte_data(client, reg); 258 259 value = i2c_smbus_read_word_data(client, reg); 260 return (value < 0) ? value : swab16(value); 261 } 262 263 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) 264 { 265 if (reg == LM75_REG_CONF) 266 return i2c_smbus_write_byte_data(client, reg, value); 267 else 268 return i2c_smbus_write_word_data(client, reg, swab16(value)); 269 } 270 271 static void lm75_init_client(struct i2c_client *client) 272 { 273 int reg; 274 275 /* Enable if in shutdown mode */ 276 reg = lm75_read_value(client, LM75_REG_CONF); 277 if (reg >= 0 && (reg & 0x01)) 278 lm75_write_value(client, LM75_REG_CONF, reg & 0xfe); 279 } 280 281 static struct lm75_data *lm75_update_device(struct device *dev) 282 { 283 struct i2c_client *client = to_i2c_client(dev); 284 struct lm75_data *data = i2c_get_clientdata(client); 285 286 mutex_lock(&data->update_lock); 287 288 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 289 || !data->valid) { 290 int i; 291 dev_dbg(&client->dev, "Starting lm75 update\n"); 292 293 for (i = 0; i < ARRAY_SIZE(data->temp); i++) { 294 int status; 295 296 status = lm75_read_value(client, LM75_REG_TEMP[i]); 297 if (status < 0) 298 dev_dbg(&client->dev, "reg %d, err %d\n", 299 LM75_REG_TEMP[i], status); 300 else 301 data->temp[i] = status; 302 } 303 data->last_updated = jiffies; 304 data->valid = 1; 305 } 306 307 mutex_unlock(&data->update_lock); 308 309 return data; 310 } 311 312 static int __init sensors_lm75_init(void) 313 { 314 return i2c_add_driver(&lm75_driver); 315 } 316 317 static void __exit sensors_lm75_exit(void) 318 { 319 i2c_del_driver(&lm75_driver); 320 } 321 322 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 323 MODULE_DESCRIPTION("LM75 driver"); 324 MODULE_LICENSE("GPL"); 325 326 module_init(sensors_lm75_init); 327 module_exit(sensors_lm75_exit); 328