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 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 .id = I2C_DRIVERID_LM75, 78 .attach_adapter = lm75_attach_adapter, 79 .detach_client = lm75_detach_client, 80 }; 81 82 static ssize_t show_temp(struct device *dev, struct device_attribute *da, 83 char *buf) 84 { 85 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 86 struct lm75_data *data = lm75_update_device(dev); 87 return sprintf(buf, "%d\n", 88 LM75_TEMP_FROM_REG(data->temp[attr->index])); 89 } 90 91 static ssize_t set_temp(struct device *dev, struct device_attribute *da, 92 const char *buf, size_t count) 93 { 94 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 95 struct i2c_client *client = to_i2c_client(dev); 96 struct lm75_data *data = i2c_get_clientdata(client); 97 int nr = attr->index; 98 long temp = simple_strtol(buf, NULL, 10); 99 100 mutex_lock(&data->update_lock); 101 data->temp[nr] = LM75_TEMP_TO_REG(temp); 102 lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]); 103 mutex_unlock(&data->update_lock); 104 return count; 105 } 106 107 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 108 show_temp, set_temp, 1); 109 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, 110 show_temp, set_temp, 2); 111 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0); 112 113 static int lm75_attach_adapter(struct i2c_adapter *adapter) 114 { 115 if (!(adapter->class & I2C_CLASS_HWMON)) 116 return 0; 117 return i2c_probe(adapter, &addr_data, lm75_detect); 118 } 119 120 static struct attribute *lm75_attributes[] = { 121 &sensor_dev_attr_temp1_input.dev_attr.attr, 122 &sensor_dev_attr_temp1_max.dev_attr.attr, 123 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, 124 125 NULL 126 }; 127 128 static const struct attribute_group lm75_group = { 129 .attrs = lm75_attributes, 130 }; 131 132 /* This function is called by i2c_probe */ 133 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind) 134 { 135 int i; 136 struct i2c_client *new_client; 137 struct lm75_data *data; 138 int err = 0; 139 const char *name = ""; 140 141 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 142 I2C_FUNC_SMBUS_WORD_DATA)) 143 goto exit; 144 145 /* OK. For now, we presume we have a valid client. We now create the 146 client structure, even though we cannot fill it completely yet. 147 But it allows us to access lm75_{read,write}_value. */ 148 if (!(data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL))) { 149 err = -ENOMEM; 150 goto exit; 151 } 152 153 new_client = &data->client; 154 i2c_set_clientdata(new_client, data); 155 new_client->addr = address; 156 new_client->adapter = adapter; 157 new_client->driver = &lm75_driver; 158 new_client->flags = 0; 159 160 /* Now, we do the remaining detection. There is no identification- 161 dedicated register so we have to rely on several tricks: 162 unused bits, registers cycling over 8-address boundaries, 163 addresses 0x04-0x07 returning the last read value. 164 The cycling+unused addresses combination is not tested, 165 since it would significantly slow the detection down and would 166 hardly add any value. */ 167 if (kind < 0) { 168 int cur, conf, hyst, os; 169 170 /* Unused addresses */ 171 cur = i2c_smbus_read_word_data(new_client, 0); 172 conf = i2c_smbus_read_byte_data(new_client, 1); 173 hyst = i2c_smbus_read_word_data(new_client, 2); 174 if (i2c_smbus_read_word_data(new_client, 4) != hyst 175 || i2c_smbus_read_word_data(new_client, 5) != hyst 176 || i2c_smbus_read_word_data(new_client, 6) != hyst 177 || i2c_smbus_read_word_data(new_client, 7) != hyst) 178 goto exit_free; 179 os = i2c_smbus_read_word_data(new_client, 3); 180 if (i2c_smbus_read_word_data(new_client, 4) != os 181 || i2c_smbus_read_word_data(new_client, 5) != os 182 || i2c_smbus_read_word_data(new_client, 6) != os 183 || i2c_smbus_read_word_data(new_client, 7) != os) 184 goto exit_free; 185 186 /* Unused bits */ 187 if (conf & 0xe0) 188 goto exit_free; 189 190 /* Addresses cycling */ 191 for (i = 8; i < 0xff; i += 8) 192 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 193 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 194 || i2c_smbus_read_word_data(new_client, i + 3) != os) 195 goto exit_free; 196 } 197 198 /* Determine the chip type - only one kind supported! */ 199 if (kind <= 0) 200 kind = lm75; 201 202 if (kind == lm75) { 203 name = "lm75"; 204 } 205 206 /* Fill in the remaining client fields and put it into the global list */ 207 strlcpy(new_client->name, name, I2C_NAME_SIZE); 208 data->valid = 0; 209 mutex_init(&data->update_lock); 210 211 /* Tell the I2C layer a new client has arrived */ 212 if ((err = i2c_attach_client(new_client))) 213 goto exit_free; 214 215 /* Initialize the LM75 chip */ 216 lm75_init_client(new_client); 217 218 /* Register sysfs hooks */ 219 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm75_group))) 220 goto exit_detach; 221 222 data->hwmon_dev = hwmon_device_register(&new_client->dev); 223 if (IS_ERR(data->hwmon_dev)) { 224 err = PTR_ERR(data->hwmon_dev); 225 goto exit_remove; 226 } 227 228 return 0; 229 230 exit_remove: 231 sysfs_remove_group(&new_client->dev.kobj, &lm75_group); 232 exit_detach: 233 i2c_detach_client(new_client); 234 exit_free: 235 kfree(data); 236 exit: 237 return err; 238 } 239 240 static int lm75_detach_client(struct i2c_client *client) 241 { 242 struct lm75_data *data = i2c_get_clientdata(client); 243 hwmon_device_unregister(data->hwmon_dev); 244 sysfs_remove_group(&client->dev.kobj, &lm75_group); 245 i2c_detach_client(client); 246 kfree(data); 247 return 0; 248 } 249 250 /* All registers are word-sized, except for the configuration register. 251 LM75 uses a high-byte first convention, which is exactly opposite to 252 the usual practice. */ 253 static int lm75_read_value(struct i2c_client *client, u8 reg) 254 { 255 if (reg == LM75_REG_CONF) 256 return i2c_smbus_read_byte_data(client, reg); 257 else 258 return swab16(i2c_smbus_read_word_data(client, reg)); 259 } 260 261 /* All registers are word-sized, except for the configuration register. 262 LM75 uses a high-byte first convention, which is exactly opposite to 263 the usual practice. */ 264 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) 265 { 266 if (reg == LM75_REG_CONF) 267 return i2c_smbus_write_byte_data(client, reg, value); 268 else 269 return i2c_smbus_write_word_data(client, reg, swab16(value)); 270 } 271 272 static void lm75_init_client(struct i2c_client *client) 273 { 274 int reg; 275 276 /* Enable if in shutdown mode */ 277 reg = lm75_read_value(client, LM75_REG_CONF); 278 if (reg >= 0 && (reg & 0x01)) 279 lm75_write_value(client, LM75_REG_CONF, reg & 0xfe); 280 } 281 282 static struct lm75_data *lm75_update_device(struct device *dev) 283 { 284 struct i2c_client *client = to_i2c_client(dev); 285 struct lm75_data *data = i2c_get_clientdata(client); 286 287 mutex_lock(&data->update_lock); 288 289 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 290 || !data->valid) { 291 int i; 292 dev_dbg(&client->dev, "Starting lm75 update\n"); 293 294 for (i = 0; i < ARRAY_SIZE(data->temp); i++) 295 data->temp[i] = lm75_read_value(client, 296 LM75_REG_TEMP[i]); 297 data->last_updated = jiffies; 298 data->valid = 1; 299 } 300 301 mutex_unlock(&data->update_lock); 302 303 return data; 304 } 305 306 static int __init sensors_lm75_init(void) 307 { 308 return i2c_add_driver(&lm75_driver); 309 } 310 311 static void __exit sensors_lm75_exit(void) 312 { 313 i2c_del_driver(&lm75_driver); 314 } 315 316 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 317 MODULE_DESCRIPTION("LM75 driver"); 318 MODULE_LICENSE("GPL"); 319 320 module_init(sensors_lm75_init); 321 module_exit(sensors_lm75_exit); 322