drivers/hwmon/tmp421.c

   1 /* tmp421.c
   2  *
   3  * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
   4  * Preliminary support by:
   5  * Melvin Rook, Raymond Ng
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 /*
  23  * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
  24  * Supported models: TMP421, TMP422, TMP423
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/slab.h>
  30 #include <linux/jiffies.h>
  31 #include <linux/i2c.h>
  32 #include <linux/hwmon.h>
  33 #include <linux/hwmon-sysfs.h>
  34 #include <linux/err.h>
  35 #include <linux/mutex.h>
  36 #include <linux/sysfs.h>
  37
  38 /* Addresses to scan */
  39 static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
  40                                              I2C_CLIENT_END };
  41
  42 enum chips { tmp421, tmp422, tmp423 };
  43
  44 /* The TMP421 registers */
  45 #define TMP421_CONFIG_REG_1                     0x09
  46 #define TMP421_CONVERSION_RATE_REG              0x0B
  47 #define TMP421_MANUFACTURER_ID_REG              0xFE
  48 #define TMP421_DEVICE_ID_REG                    0xFF
  49
  50 static const u8 TMP421_TEMP_MSB[4]              = { 0x00, 0x01, 0x02, 0x03 };
  51 static const u8 TMP421_TEMP_LSB[4]              = { 0x10, 0x11, 0x12, 0x13 };
  52
  53 /* Flags */
  54 #define TMP421_CONFIG_SHUTDOWN                  0x40
  55 #define TMP421_CONFIG_RANGE                     0x04
  56
  57 /* Manufacturer / Device ID's */
  58 #define TMP421_MANUFACTURER_ID                  0x55
  59 #define TMP421_DEVICE_ID                        0x21
  60 #define TMP422_DEVICE_ID                        0x22
  61 #define TMP423_DEVICE_ID                        0x23
  62
  63 static const struct i2c_device_id tmp421_id[] = {
  64         { "tmp421", 2 },
  65         { "tmp422", 3 },
  66         { "tmp423", 4 },
  67         { }
  68 };
  69 MODULE_DEVICE_TABLE(i2c, tmp421_id);
  70
  71 struct tmp421_data {
  72         struct i2c_client *client;
  73         struct mutex update_lock;
  74         char valid;
  75         unsigned long last_updated;
  76         int channels;
  77         u8 config;
  78         s16 temp[4];
  79 };
  80
  81 static int temp_from_s16(s16 reg)
  82 {
  83         /* Mask out status bits */
  84         int temp = reg & ~0xf;
  85
  86         return (temp * 1000 + 128) / 256;
  87 }
  88
  89 static int temp_from_u16(u16 reg)
  90 {
  91         /* Mask out status bits */
  92         int temp = reg & ~0xf;
  93
  94         /* Add offset for extended temperature range. */
  95         temp -= 64 * 256;
  96
  97         return (temp * 1000 + 128) / 256;
  98 }
  99
 100 static struct tmp421_data *tmp421_update_device(struct device *dev)
 101 {
 102         struct tmp421_data *data = dev_get_drvdata(dev);
 103         struct i2c_client *client = data->client;
 104         int i;
 105
 106         mutex_lock(&data->update_lock);
 107
 108         if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
 109                 data->config = i2c_smbus_read_byte_data(client,
 110                         TMP421_CONFIG_REG_1);
 111
 112                 for (i = 0; i < data->channels; i++) {
 113                         data->temp[i] = i2c_smbus_read_byte_data(client,
 114                                 TMP421_TEMP_MSB[i]) << 8;
 115                         data->temp[i] |= i2c_smbus_read_byte_data(client,
 116                                 TMP421_TEMP_LSB[i]);
 117                 }
 118                 data->last_updated = jiffies;
 119                 data->valid = 1;
 120         }
 121
 122         mutex_unlock(&data->update_lock);
 123
 124         return data;
 125 }
 126
 127 static ssize_t show_temp_value(struct device *dev,
 128                                struct device_attribute *devattr, char *buf)
 129 {
 130         int index = to_sensor_dev_attr(devattr)->index;
 131         struct tmp421_data *data = tmp421_update_device(dev);
 132         int temp;
 133
 134         mutex_lock(&data->update_lock);
 135         if (data->config & TMP421_CONFIG_RANGE)
 136                 temp = temp_from_u16(data->temp[index]);
 137         else
 138                 temp = temp_from_s16(data->temp[index]);
 139         mutex_unlock(&data->update_lock);
 140
 141         return sprintf(buf, "%d\n", temp);
 142 }
 143
 144 static ssize_t show_fault(struct device *dev,
 145                           struct device_attribute *devattr, char *buf)
 146 {
 147         int index = to_sensor_dev_attr(devattr)->index;
 148         struct tmp421_data *data = tmp421_update_device(dev);
 149
 150         /*
 151          * The OPEN bit signals a fault. This is bit 0 of the temperature
 152          * register (low byte).
 153          */
 154         if (data->temp[index] & 0x01)
 155                 return sprintf(buf, "1\n");
 156         else
 157                 return sprintf(buf, "0\n");
 158 }
 159
 160 static umode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
 161                                 int n)
 162 {
 163         struct device *dev = container_of(kobj, struct device, kobj);
 164         struct tmp421_data *data = dev_get_drvdata(dev);
 165         struct device_attribute *devattr;
 166         unsigned int index;
 167
 168         devattr = container_of(a, struct device_attribute, attr);
 169         index = to_sensor_dev_attr(devattr)->index;
 170
 171         if (index < data->channels)
 172                 return a->mode;
 173
 174         return 0;
 175 }
 176
 177 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_value, NULL, 0);
 178 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_value, NULL, 1);
 179 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
 180 static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp_value, NULL, 2);
 181 static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
 182 static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp_value, NULL, 3);
 183 static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
 184
 185 static struct attribute *tmp421_attr[] = {
 186         &sensor_dev_attr_temp1_input.dev_attr.attr,
 187         &sensor_dev_attr_temp2_input.dev_attr.attr,
 188         &sensor_dev_attr_temp2_fault.dev_attr.attr,
 189         &sensor_dev_attr_temp3_input.dev_attr.attr,
 190         &sensor_dev_attr_temp3_fault.dev_attr.attr,
 191         &sensor_dev_attr_temp4_input.dev_attr.attr,
 192         &sensor_dev_attr_temp4_fault.dev_attr.attr,
 193         NULL
 194 };
 195
 196 static const struct attribute_group tmp421_group = {
 197         .attrs = tmp421_attr,
 198         .is_visible = tmp421_is_visible,
 199 };
 200
 201 static const struct attribute_group *tmp421_groups[] = {
 202         &tmp421_group,
 203         NULL
 204 };
 205
 206 static int tmp421_init_client(struct i2c_client *client)
 207 {
 208         int config, config_orig;
 209
 210         /* Set the conversion rate to 2 Hz */
 211         i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 212
 213         /* Start conversions (disable shutdown if necessary) */
 214         config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 215         if (config < 0) {
 216                 dev_err(&client->dev,
 217                         "Could not read configuration register (%d)\n", config);
 218                 return config;
 219         }
 220
 221         config_orig = config;
 222         config &= ~TMP421_CONFIG_SHUTDOWN;
 223
 224         if (config != config_orig) {
 225                 dev_info(&client->dev, "Enable monitoring chip\n");
 226                 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 227         }
 228
 229         return 0;
 230 }
 231
 232 static int tmp421_detect(struct i2c_client *client,
 233                          struct i2c_board_info *info)
 234 {
 235         enum chips kind;
 236         struct i2c_adapter *adapter = client->adapter;
 237         const char *names[] = { "TMP421", "TMP422", "TMP423" };
 238         u8 reg;
 239
 240         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 241                 return -ENODEV;
 242
 243         reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
 244         if (reg != TMP421_MANUFACTURER_ID)
 245                 return -ENODEV;
 246
 247         reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
 248         switch (reg) {
 249         case TMP421_DEVICE_ID:
 250                 kind = tmp421;
 251                 break;
 252         case TMP422_DEVICE_ID:
 253                 kind = tmp422;
 254                 break;
 255         case TMP423_DEVICE_ID:
 256                 kind = tmp423;
 257                 break;
 258         default:
 259                 return -ENODEV;
 260         }
 261
 262         strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
 263         dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 264                  names[kind], client->addr);
 265
 266         return 0;
 267 }
 268
 269 static int tmp421_probe(struct i2c_client *client,
 270                         const struct i2c_device_id *id)
 271 {
 272         struct device *dev = &client->dev;
 273         struct device *hwmon_dev;
 274         struct tmp421_data *data;
 275         int err;
 276
 277         data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
 278         if (!data)
 279                 return -ENOMEM;
 280
 281         mutex_init(&data->update_lock);
 282         data->channels = id->driver_data;
 283         data->client = client;
 284
 285         err = tmp421_init_client(client);
 286         if (err)
 287                 return err;
 288
 289         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 290                                                            data, tmp421_groups);
 291         return PTR_ERR_OR_ZERO(hwmon_dev);
 292 }
 293
 294 static struct i2c_driver tmp421_driver = {
 295         .class = I2C_CLASS_HWMON,
 296         .driver = {
 297                 .name   = "tmp421",
 298         },
 299         .probe = tmp421_probe,
 300         .id_table = tmp421_id,
 301         .detect = tmp421_detect,
 302         .address_list = normal_i2c,
 303 };
 304
 305 module_i2c_driver(tmp421_driver);
 306
 307 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 308 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423 temperature sensor driver");
 309 MODULE_LICENSE("GPL");