drivers/hwmon/lm73.c

   1 /*
   2  * LM73 Sensor driver
   3  * Based on LM75
   4  *
   5  * Copyright (C) 2007, CenoSYS (www.cenosys.com).
   6  * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu).
   7  *
   8  * Guillaume Ligneul <guillaume.ligneul@gmail.com>
   9  * Adrien Demarez <adrien.demarez@bolloretelecom.eu>
  10  * Jeremy Laine <jeremy.laine@bolloretelecom.eu>
  11  * Chris Verges <kg4ysn@gmail.com>
  12  *
  13  * This software program is licensed subject to the GNU General Public License
  14  * (GPL).Version 2,June 1991, available at
  15  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/i2c.h>
  21 #include <linux/hwmon.h>
  22 #include <linux/hwmon-sysfs.h>
  23 #include <linux/err.h>
  24
  25
  26 /* Addresses scanned */
  27 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
  28                                         0x4d, 0x4e, I2C_CLIENT_END };
  29
  30 /* LM73 registers */
  31 #define LM73_REG_INPUT          0x00
  32 #define LM73_REG_CONF           0x01
  33 #define LM73_REG_MAX            0x02
  34 #define LM73_REG_MIN            0x03
  35 #define LM73_REG_CTRL           0x04
  36 #define LM73_REG_ID             0x07
  37
  38 #define LM73_ID                 0x9001  /* 0x0190, byte-swapped */
  39 #define DRVNAME                 "lm73"
  40 #define LM73_TEMP_MIN           (-256000 / 250)
  41 #define LM73_TEMP_MAX           (255750 / 250)
  42
  43 #define LM73_CTRL_RES_SHIFT     5
  44 #define LM73_CTRL_RES_MASK      (BIT(5) | BIT(6))
  45 #define LM73_CTRL_TO_MASK       BIT(7)
  46
  47 #define LM73_CTRL_HI_SHIFT      2
  48 #define LM73_CTRL_LO_SHIFT      1
  49
  50 static const unsigned short lm73_convrates[] = {
  51         14,     /* 11-bits (0.25000 C/LSB): RES1 Bit = 0, RES0 Bit = 0 */
  52         28,     /* 12-bits (0.12500 C/LSB): RES1 Bit = 0, RES0 Bit = 1 */
  53         56,     /* 13-bits (0.06250 C/LSB): RES1 Bit = 1, RES0 Bit = 0 */
  54         112,    /* 14-bits (0.03125 C/LSB): RES1 Bit = 1, RES0 Bit = 1 */
  55 };
  56
  57 struct lm73_data {
  58         struct device *hwmon_dev;
  59         struct mutex lock;
  60         u8 ctrl;                        /* control register value */
  61 };
  62
  63 /*-----------------------------------------------------------------------*/
  64
  65 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
  66                         const char *buf, size_t count)
  67 {
  68         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  69         struct i2c_client *client = to_i2c_client(dev);
  70         long temp;
  71         short value;
  72         s32 err;
  73
  74         int status = kstrtol(buf, 10, &temp);
  75         if (status < 0)
  76                 return status;
  77
  78         /* Write value */
  79         value = clamp_val(temp / 250, LM73_TEMP_MIN, LM73_TEMP_MAX) << 5;
  80         err = i2c_smbus_write_word_swapped(client, attr->index, value);
  81         return (err < 0) ? err : count;
  82 }
  83
  84 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  85                          char *buf)
  86 {
  87         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  88         struct i2c_client *client = to_i2c_client(dev);
  89         int temp;
  90
  91         s32 err = i2c_smbus_read_word_swapped(client, attr->index);
  92         if (err < 0)
  93                 return err;
  94
  95         /* use integer division instead of equivalent right shift to
  96            guarantee arithmetic shift and preserve the sign */
  97         temp = (((s16) err) * 250) / 32;
  98         return scnprintf(buf, PAGE_SIZE, "%d\n", temp);
  99 }
 100
 101 static ssize_t set_convrate(struct device *dev, struct device_attribute *da,
 102                             const char *buf, size_t count)
 103 {
 104         struct i2c_client *client = to_i2c_client(dev);
 105         struct lm73_data *data = i2c_get_clientdata(client);
 106         unsigned long convrate;
 107         s32 err;
 108         int res = 0;
 109
 110         err = kstrtoul(buf, 10, &convrate);
 111         if (err < 0)
 112                 return err;
 113
 114         /*
 115          * Convert the desired conversion rate into register bits.
 116          * res is already initialized, and everything past the second-to-last
 117          * value in the array is treated as belonging to the last value
 118          * in the array.
 119          */
 120         while (res < (ARRAY_SIZE(lm73_convrates) - 1) &&
 121                         convrate > lm73_convrates[res])
 122                 res++;
 123
 124         mutex_lock(&data->lock);
 125         data->ctrl &= LM73_CTRL_TO_MASK;
 126         data->ctrl |= res << LM73_CTRL_RES_SHIFT;
 127         err = i2c_smbus_write_byte_data(client, LM73_REG_CTRL, data->ctrl);
 128         mutex_unlock(&data->lock);
 129
 130         if (err < 0)
 131                 return err;
 132
 133         return count;
 134 }
 135
 136 static ssize_t show_convrate(struct device *dev, struct device_attribute *da,
 137                              char *buf)
 138 {
 139         struct i2c_client *client = to_i2c_client(dev);
 140         struct lm73_data *data = i2c_get_clientdata(client);
 141         int res;
 142
 143         res = (data->ctrl & LM73_CTRL_RES_MASK) >> LM73_CTRL_RES_SHIFT;
 144         return scnprintf(buf, PAGE_SIZE, "%hu\n", lm73_convrates[res]);
 145 }
 146
 147 static ssize_t show_maxmin_alarm(struct device *dev,
 148                                  struct device_attribute *da, char *buf)
 149 {
 150         struct i2c_client *client = to_i2c_client(dev);
 151         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 152         struct lm73_data *data = i2c_get_clientdata(client);
 153         s32 ctrl;
 154
 155         mutex_lock(&data->lock);
 156         ctrl = i2c_smbus_read_byte_data(client, LM73_REG_CTRL);
 157         if (ctrl < 0)
 158                 goto abort;
 159         data->ctrl = ctrl;
 160         mutex_unlock(&data->lock);
 161
 162         return scnprintf(buf, PAGE_SIZE, "%d\n", (ctrl >> attr->index) & 1);
 163
 164 abort:
 165         mutex_unlock(&data->lock);
 166         return ctrl;
 167 }
 168
 169 /*-----------------------------------------------------------------------*/
 170
 171 /* sysfs attributes for hwmon */
 172
 173 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 174                         show_temp, set_temp, LM73_REG_MAX);
 175 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
 176                         show_temp, set_temp, LM73_REG_MIN);
 177 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
 178                         show_temp, NULL, LM73_REG_INPUT);
 179 static SENSOR_DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO,
 180                         show_convrate, set_convrate, 0);
 181 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO,
 182                         show_maxmin_alarm, NULL, LM73_CTRL_HI_SHIFT);
 183 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO,
 184                         show_maxmin_alarm, NULL, LM73_CTRL_LO_SHIFT);
 185
 186 static struct attribute *lm73_attributes[] = {
 187         &sensor_dev_attr_temp1_input.dev_attr.attr,
 188         &sensor_dev_attr_temp1_max.dev_attr.attr,
 189         &sensor_dev_attr_temp1_min.dev_attr.attr,
 190         &sensor_dev_attr_update_interval.dev_attr.attr,
 191         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 192         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 193         NULL
 194 };
 195
 196 static const struct attribute_group lm73_group = {
 197         .attrs = lm73_attributes,
 198 };
 199
 200 /*-----------------------------------------------------------------------*/
 201
 202 /* device probe and removal */
 203
 204 static int
 205 lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
 206 {
 207         int status;
 208         struct lm73_data *data;
 209         int ctrl;
 210
 211         data = devm_kzalloc(&client->dev, sizeof(struct lm73_data),
 212                             GFP_KERNEL);
 213         if (!data)
 214                 return -ENOMEM;
 215
 216         i2c_set_clientdata(client, data);
 217         mutex_init(&data->lock);
 218
 219         ctrl = i2c_smbus_read_byte_data(client, LM73_REG_CTRL);
 220         if (ctrl < 0)
 221                 return ctrl;
 222         data->ctrl = ctrl;
 223
 224         /* Register sysfs hooks */
 225         status = sysfs_create_group(&client->dev.kobj, &lm73_group);
 226         if (status)
 227                 return status;
 228
 229         data->hwmon_dev = hwmon_device_register(&client->dev);
 230         if (IS_ERR(data->hwmon_dev)) {
 231                 status = PTR_ERR(data->hwmon_dev);
 232                 goto exit_remove;
 233         }
 234
 235         dev_info(&client->dev, "%s: sensor '%s'\n",
 236                  dev_name(data->hwmon_dev), client->name);
 237
 238         return 0;
 239
 240 exit_remove:
 241         sysfs_remove_group(&client->dev.kobj, &lm73_group);
 242         return status;
 243 }
 244
 245 static int lm73_remove(struct i2c_client *client)
 246 {
 247         struct lm73_data *data = i2c_get_clientdata(client);
 248
 249         hwmon_device_unregister(data->hwmon_dev);
 250         sysfs_remove_group(&client->dev.kobj, &lm73_group);
 251         return 0;
 252 }
 253
 254 static const struct i2c_device_id lm73_ids[] = {
 255         { "lm73", 0 },
 256         { /* LIST END */ }
 257 };
 258 MODULE_DEVICE_TABLE(i2c, lm73_ids);
 259
 260 /* Return 0 if detection is successful, -ENODEV otherwise */
 261 static int lm73_detect(struct i2c_client *new_client,
 262                         struct i2c_board_info *info)
 263 {
 264         struct i2c_adapter *adapter = new_client->adapter;
 265         int id, ctrl, conf;
 266
 267         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 268                                         I2C_FUNC_SMBUS_WORD_DATA))
 269                 return -ENODEV;
 270
 271         /*
 272          * Do as much detection as possible with byte reads first, as word
 273          * reads can confuse other devices.
 274          */
 275         ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
 276         if (ctrl < 0 || (ctrl & 0x10))
 277                 return -ENODEV;
 278
 279         conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);
 280         if (conf < 0 || (conf & 0x0c))
 281                 return -ENODEV;
 282
 283         id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);
 284         if (id < 0 || id != (LM73_ID & 0xff))
 285                 return -ENODEV;
 286
 287         /* Check device ID */
 288         id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
 289         if (id < 0 || id != LM73_ID)
 290                 return -ENODEV;
 291
 292         strlcpy(info->type, "lm73", I2C_NAME_SIZE);
 293
 294         return 0;
 295 }
 296
 297 static struct i2c_driver lm73_driver = {
 298         .class          = I2C_CLASS_HWMON,
 299         .driver = {
 300                 .name   = "lm73",
 301         },
 302         .probe          = lm73_probe,
 303         .remove         = lm73_remove,
 304         .id_table       = lm73_ids,
 305         .detect         = lm73_detect,
 306         .address_list   = normal_i2c,
 307 };
 308
 309 module_i2c_driver(lm73_driver);
 310
 311 MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
 312 MODULE_DESCRIPTION("LM73 driver");
 313 MODULE_LICENSE("GPL");