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