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 i2c_client *client;
  59         struct mutex lock;
  60         u8 ctrl;                        /* control register value */
  61 };
  62
  63 /*-----------------------------------------------------------------------*/
  64
  65 static ssize_t temp_store(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 lm73_data *data = dev_get_drvdata(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(data->client, attr->index, value);
  81         return (err < 0) ? err : count;
  82 }
  83
  84 static ssize_t temp_show(struct device *dev, struct device_attribute *da,
  85                          char *buf)
  86 {
  87         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  88         struct lm73_data *data = dev_get_drvdata(dev);
  89         int temp;
  90
  91         s32 err = i2c_smbus_read_word_swapped(data->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 convrate_store(struct device *dev, struct device_attribute *da,
 102                               const char *buf, size_t count)
 103 {
 104         struct lm73_data *data = dev_get_drvdata(dev);
 105         unsigned long convrate;
 106         s32 err;
 107         int res = 0;
 108
 109         err = kstrtoul(buf, 10, &convrate);
 110         if (err < 0)
 111                 return err;
 112
 113         /*
 114          * Convert the desired conversion rate into register bits.
 115          * res is already initialized, and everything past the second-to-last
 116          * value in the array is treated as belonging to the last value
 117          * in the array.
 118          */
 119         while (res < (ARRAY_SIZE(lm73_convrates) - 1) &&
 120                         convrate > lm73_convrates[res])
 121                 res++;
 122
 123         mutex_lock(&data->lock);
 124         data->ctrl &= LM73_CTRL_TO_MASK;
 125         data->ctrl |= res << LM73_CTRL_RES_SHIFT;
 126         err = i2c_smbus_write_byte_data(data->client, LM73_REG_CTRL,
 127                                         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 convrate_show(struct device *dev, struct device_attribute *da,
 137                              char *buf)
 138 {
 139         struct lm73_data *data = dev_get_drvdata(dev);
 140         int res;
 141
 142         res = (data->ctrl & LM73_CTRL_RES_MASK) >> LM73_CTRL_RES_SHIFT;
 143         return scnprintf(buf, PAGE_SIZE, "%hu\n", lm73_convrates[res]);
 144 }
 145
 146 static ssize_t maxmin_alarm_show(struct device *dev,
 147                                  struct device_attribute *da, char *buf)
 148 {
 149         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 150         struct lm73_data *data = dev_get_drvdata(dev);
 151         s32 ctrl;
 152
 153         mutex_lock(&data->lock);
 154         ctrl = i2c_smbus_read_byte_data(data->client, LM73_REG_CTRL);
 155         if (ctrl < 0)
 156                 goto abort;
 157         data->ctrl = ctrl;
 158         mutex_unlock(&data->lock);
 159
 160         return scnprintf(buf, PAGE_SIZE, "%d\n", (ctrl >> attr->index) & 1);
 161
 162 abort:
 163         mutex_unlock(&data->lock);
 164         return ctrl;
 165 }
 166
 167 /*-----------------------------------------------------------------------*/
 168
 169 /* sysfs attributes for hwmon */
 170
 171 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, LM73_REG_MAX);
 172 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, LM73_REG_MIN);
 173 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, LM73_REG_INPUT);
 174 static SENSOR_DEVICE_ATTR_RW(update_interval, convrate, 0);
 175 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, maxmin_alarm,
 176                              LM73_CTRL_HI_SHIFT);
 177 static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, maxmin_alarm,
 178                              LM73_CTRL_LO_SHIFT);
 179
 180 static struct attribute *lm73_attrs[] = {
 181         &sensor_dev_attr_temp1_input.dev_attr.attr,
 182         &sensor_dev_attr_temp1_max.dev_attr.attr,
 183         &sensor_dev_attr_temp1_min.dev_attr.attr,
 184         &sensor_dev_attr_update_interval.dev_attr.attr,
 185         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 186         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 187         NULL
 188 };
 189 ATTRIBUTE_GROUPS(lm73);
 190
 191 /*-----------------------------------------------------------------------*/
 192
 193 /* device probe and removal */
 194
 195 static int
 196 lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
 197 {
 198         struct device *dev = &client->dev;
 199         struct device *hwmon_dev;
 200         struct lm73_data *data;
 201         int ctrl;
 202
 203         data = devm_kzalloc(dev, sizeof(struct lm73_data), GFP_KERNEL);
 204         if (!data)
 205                 return -ENOMEM;
 206
 207         data->client = client;
 208         mutex_init(&data->lock);
 209
 210         ctrl = i2c_smbus_read_byte_data(client, LM73_REG_CTRL);
 211         if (ctrl < 0)
 212                 return ctrl;
 213         data->ctrl = ctrl;
 214
 215         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 216                                                            data, lm73_groups);
 217         if (IS_ERR(hwmon_dev))
 218                 return PTR_ERR(hwmon_dev);
 219
 220         dev_info(dev, "sensor '%s'\n", client->name);
 221
 222         return 0;
 223 }
 224
 225 static const struct i2c_device_id lm73_ids[] = {
 226         { "lm73", 0 },
 227         { /* LIST END */ }
 228 };
 229 MODULE_DEVICE_TABLE(i2c, lm73_ids);
 230
 231 /* Return 0 if detection is successful, -ENODEV otherwise */
 232 static int lm73_detect(struct i2c_client *new_client,
 233                         struct i2c_board_info *info)
 234 {
 235         struct i2c_adapter *adapter = new_client->adapter;
 236         int id, ctrl, conf;
 237
 238         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 239                                         I2C_FUNC_SMBUS_WORD_DATA))
 240                 return -ENODEV;
 241
 242         /*
 243          * Do as much detection as possible with byte reads first, as word
 244          * reads can confuse other devices.
 245          */
 246         ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
 247         if (ctrl < 0 || (ctrl & 0x10))
 248                 return -ENODEV;
 249
 250         conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);
 251         if (conf < 0 || (conf & 0x0c))
 252                 return -ENODEV;
 253
 254         id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);
 255         if (id < 0 || id != (LM73_ID & 0xff))
 256                 return -ENODEV;
 257
 258         /* Check device ID */
 259         id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
 260         if (id < 0 || id != LM73_ID)
 261                 return -ENODEV;
 262
 263         strlcpy(info->type, "lm73", I2C_NAME_SIZE);
 264
 265         return 0;
 266 }
 267
 268 static struct i2c_driver lm73_driver = {
 269         .class          = I2C_CLASS_HWMON,
 270         .driver = {
 271                 .name   = "lm73",
 272         },
 273         .probe          = lm73_probe,
 274         .id_table       = lm73_ids,
 275         .detect         = lm73_detect,
 276         .address_list   = normal_i2c,
 277 };
 278
 279 module_i2c_driver(lm73_driver);
 280
 281 MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
 282 MODULE_DESCRIPTION("LM73 driver");
 283 MODULE_LICENSE("GPL");