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/err.h> 28 #include <linux/mutex.h> 29 #include "lm75.h" 30 31 32 /* Addresses to scan */ 33 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, 34 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; 35 36 /* Insmod parameters */ 37 I2C_CLIENT_INSMOD_1(lm75); 38 39 /* Many LM75 constants specified below */ 40 41 /* The LM75 registers */ 42 #define LM75_REG_TEMP 0x00 43 #define LM75_REG_CONF 0x01 44 #define LM75_REG_TEMP_HYST 0x02 45 #define LM75_REG_TEMP_OS 0x03 46 47 /* Each client has this additional data */ 48 struct lm75_data { 49 struct i2c_client client; 50 struct class_device *class_dev; 51 struct mutex update_lock; 52 char valid; /* !=0 if following fields are valid */ 53 unsigned long last_updated; /* In jiffies */ 54 u16 temp_input; /* Register values */ 55 u16 temp_max; 56 u16 temp_hyst; 57 }; 58 59 static int lm75_attach_adapter(struct i2c_adapter *adapter); 60 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind); 61 static void lm75_init_client(struct i2c_client *client); 62 static int lm75_detach_client(struct i2c_client *client); 63 static int lm75_read_value(struct i2c_client *client, u8 reg); 64 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value); 65 static struct lm75_data *lm75_update_device(struct device *dev); 66 67 68 /* This is the driver that will be inserted */ 69 static struct i2c_driver lm75_driver = { 70 .driver = { 71 .name = "lm75", 72 }, 73 .id = I2C_DRIVERID_LM75, 74 .attach_adapter = lm75_attach_adapter, 75 .detach_client = lm75_detach_client, 76 }; 77 78 #define show(value) \ 79 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 80 { \ 81 struct lm75_data *data = lm75_update_device(dev); \ 82 return sprintf(buf, "%d\n", LM75_TEMP_FROM_REG(data->value)); \ 83 } 84 show(temp_max); 85 show(temp_hyst); 86 show(temp_input); 87 88 #define set(value, reg) \ 89 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \ 90 { \ 91 struct i2c_client *client = to_i2c_client(dev); \ 92 struct lm75_data *data = i2c_get_clientdata(client); \ 93 int temp = simple_strtoul(buf, NULL, 10); \ 94 \ 95 mutex_lock(&data->update_lock); \ 96 data->value = LM75_TEMP_TO_REG(temp); \ 97 lm75_write_value(client, reg, data->value); \ 98 mutex_unlock(&data->update_lock); \ 99 return count; \ 100 } 101 set(temp_max, LM75_REG_TEMP_OS); 102 set(temp_hyst, LM75_REG_TEMP_HYST); 103 104 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max); 105 static DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, show_temp_hyst, set_temp_hyst); 106 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL); 107 108 static int lm75_attach_adapter(struct i2c_adapter *adapter) 109 { 110 if (!(adapter->class & I2C_CLASS_HWMON)) 111 return 0; 112 return i2c_probe(adapter, &addr_data, lm75_detect); 113 } 114 115 /* This function is called by i2c_probe */ 116 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind) 117 { 118 int i; 119 struct i2c_client *new_client; 120 struct lm75_data *data; 121 int err = 0; 122 const char *name = ""; 123 124 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 125 I2C_FUNC_SMBUS_WORD_DATA)) 126 goto exit; 127 128 /* OK. For now, we presume we have a valid client. We now create the 129 client structure, even though we cannot fill it completely yet. 130 But it allows us to access lm75_{read,write}_value. */ 131 if (!(data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL))) { 132 err = -ENOMEM; 133 goto exit; 134 } 135 136 new_client = &data->client; 137 i2c_set_clientdata(new_client, data); 138 new_client->addr = address; 139 new_client->adapter = adapter; 140 new_client->driver = &lm75_driver; 141 new_client->flags = 0; 142 143 /* Now, we do the remaining detection. There is no identification- 144 dedicated register so we have to rely on several tricks: 145 unused bits, registers cycling over 8-address boundaries, 146 addresses 0x04-0x07 returning the last read value. 147 The cycling+unused addresses combination is not tested, 148 since it would significantly slow the detection down and would 149 hardly add any value. */ 150 if (kind < 0) { 151 int cur, conf, hyst, os; 152 153 /* Unused addresses */ 154 cur = i2c_smbus_read_word_data(new_client, 0); 155 conf = i2c_smbus_read_byte_data(new_client, 1); 156 hyst = i2c_smbus_read_word_data(new_client, 2); 157 if (i2c_smbus_read_word_data(new_client, 4) != hyst 158 || i2c_smbus_read_word_data(new_client, 5) != hyst 159 || i2c_smbus_read_word_data(new_client, 6) != hyst 160 || i2c_smbus_read_word_data(new_client, 7) != hyst) 161 goto exit_free; 162 os = i2c_smbus_read_word_data(new_client, 3); 163 if (i2c_smbus_read_word_data(new_client, 4) != os 164 || i2c_smbus_read_word_data(new_client, 5) != os 165 || i2c_smbus_read_word_data(new_client, 6) != os 166 || i2c_smbus_read_word_data(new_client, 7) != os) 167 goto exit_free; 168 169 /* Unused bits */ 170 if (conf & 0xe0) 171 goto exit_free; 172 173 /* Addresses cycling */ 174 for (i = 8; i < 0xff; i += 8) 175 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 176 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 177 || i2c_smbus_read_word_data(new_client, i + 3) != os) 178 goto exit_free; 179 } 180 181 /* Determine the chip type - only one kind supported! */ 182 if (kind <= 0) 183 kind = lm75; 184 185 if (kind == lm75) { 186 name = "lm75"; 187 } 188 189 /* Fill in the remaining client fields and put it into the global list */ 190 strlcpy(new_client->name, name, I2C_NAME_SIZE); 191 data->valid = 0; 192 mutex_init(&data->update_lock); 193 194 /* Tell the I2C layer a new client has arrived */ 195 if ((err = i2c_attach_client(new_client))) 196 goto exit_free; 197 198 /* Initialize the LM75 chip */ 199 lm75_init_client(new_client); 200 201 /* Register sysfs hooks */ 202 data->class_dev = hwmon_device_register(&new_client->dev); 203 if (IS_ERR(data->class_dev)) { 204 err = PTR_ERR(data->class_dev); 205 goto exit_detach; 206 } 207 208 device_create_file(&new_client->dev, &dev_attr_temp1_max); 209 device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst); 210 device_create_file(&new_client->dev, &dev_attr_temp1_input); 211 212 return 0; 213 214 exit_detach: 215 i2c_detach_client(new_client); 216 exit_free: 217 kfree(data); 218 exit: 219 return err; 220 } 221 222 static int lm75_detach_client(struct i2c_client *client) 223 { 224 struct lm75_data *data = i2c_get_clientdata(client); 225 hwmon_device_unregister(data->class_dev); 226 i2c_detach_client(client); 227 kfree(data); 228 return 0; 229 } 230 231 /* All registers are word-sized, except for the configuration register. 232 LM75 uses a high-byte first convention, which is exactly opposite to 233 the usual practice. */ 234 static int lm75_read_value(struct i2c_client *client, u8 reg) 235 { 236 if (reg == LM75_REG_CONF) 237 return i2c_smbus_read_byte_data(client, reg); 238 else 239 return swab16(i2c_smbus_read_word_data(client, reg)); 240 } 241 242 /* All registers are word-sized, except for the configuration register. 243 LM75 uses a high-byte first convention, which is exactly opposite to 244 the usual practice. */ 245 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) 246 { 247 if (reg == LM75_REG_CONF) 248 return i2c_smbus_write_byte_data(client, reg, value); 249 else 250 return i2c_smbus_write_word_data(client, reg, swab16(value)); 251 } 252 253 static void lm75_init_client(struct i2c_client *client) 254 { 255 int reg; 256 257 /* Enable if in shutdown mode */ 258 reg = lm75_read_value(client, LM75_REG_CONF); 259 if (reg >= 0 && (reg & 0x01)) 260 lm75_write_value(client, LM75_REG_CONF, reg & 0xfe); 261 } 262 263 static struct lm75_data *lm75_update_device(struct device *dev) 264 { 265 struct i2c_client *client = to_i2c_client(dev); 266 struct lm75_data *data = i2c_get_clientdata(client); 267 268 mutex_lock(&data->update_lock); 269 270 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 271 || !data->valid) { 272 dev_dbg(&client->dev, "Starting lm75 update\n"); 273 274 data->temp_input = lm75_read_value(client, LM75_REG_TEMP); 275 data->temp_max = lm75_read_value(client, LM75_REG_TEMP_OS); 276 data->temp_hyst = lm75_read_value(client, LM75_REG_TEMP_HYST); 277 data->last_updated = jiffies; 278 data->valid = 1; 279 } 280 281 mutex_unlock(&data->update_lock); 282 283 return data; 284 } 285 286 static int __init sensors_lm75_init(void) 287 { 288 return i2c_add_driver(&lm75_driver); 289 } 290 291 static void __exit sensors_lm75_exit(void) 292 { 293 i2c_del_driver(&lm75_driver); 294 } 295 296 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 297 MODULE_DESCRIPTION("LM75 driver"); 298 MODULE_LICENSE("GPL"); 299 300 module_init(sensors_lm75_init); 301 module_exit(sensors_lm75_exit); 302