linux/drivers/hwmon/lm73.c
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   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 */
  27static 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
  50static 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
  57struct lm73_data {
  58        struct device *hwmon_dev;
  59        struct mutex lock;
  60        u8 ctrl;                        /* control register value */
  61};
  62
  63/*-----------------------------------------------------------------------*/
  64
  65static 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
  84static 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
 101static 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
 136static 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
 147static 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
 164abort:
 165        mutex_unlock(&data->lock);
 166        return ctrl;
 167}
 168
 169/*-----------------------------------------------------------------------*/
 170
 171/* sysfs attributes for hwmon */
 172
 173static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 174                        show_temp, set_temp, LM73_REG_MAX);
 175static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
 176                        show_temp, set_temp, LM73_REG_MIN);
 177static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
 178                        show_temp, NULL, LM73_REG_INPUT);
 179static SENSOR_DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO,
 180                        show_convrate, set_convrate, 0);
 181static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO,
 182                        show_maxmin_alarm, NULL, LM73_CTRL_HI_SHIFT);
 183static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO,
 184                        show_maxmin_alarm, NULL, LM73_CTRL_LO_SHIFT);
 185
 186static 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
 196static const struct attribute_group lm73_group = {
 197        .attrs = lm73_attributes,
 198};
 199
 200/*-----------------------------------------------------------------------*/
 201
 202/* device probe and removal */
 203
 204static int
 205lm73_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
 240exit_remove:
 241        sysfs_remove_group(&client->dev.kobj, &lm73_group);
 242        return status;
 243}
 244
 245static 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
 254static const struct i2c_device_id lm73_ids[] = {
 255        { "lm73", 0 },
 256        { /* LIST END */ }
 257};
 258MODULE_DEVICE_TABLE(i2c, lm73_ids);
 259
 260/* Return 0 if detection is successful, -ENODEV otherwise */
 261static 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
 297static 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
 309module_i2c_driver(lm73_driver);
 310
 311MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
 312MODULE_DESCRIPTION("LM73 driver");
 313MODULE_LICENSE("GPL");
 314
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