linux/drivers/hwmon/max6642.c
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   1/*
   2 * Driver for +/-1 degree C, SMBus-Compatible Remote/Local Temperature Sensor
   3 * with Overtemperature Alarm
   4 *
   5 * Copyright (C) 2011 AppearTV AS
   6 *
   7 * Derived from:
   8 *
   9 *  Based on the max1619 driver.
  10 *  Copyright (C) 2003-2004 Oleksij Rempel <bug-track@fisher-privat.net>
  11 *                          Jean Delvare <khali@linux-fr.org>
  12 *
  13 * The MAX6642 is a sensor chip made by Maxim.
  14 * It reports up to two temperatures (its own plus up to
  15 * one external one). Complete datasheet can be
  16 * obtained from Maxim's website at:
  17 *   http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf
  18 *
  19 * This program is free software; you can redistribute it and/or modify
  20 * it under the terms of the GNU General Public License as published by
  21 * the Free Software Foundation; either version 2 of the License, or
  22 * (at your option) any later version.
  23 *
  24 * This program is distributed in the hope that it will be useful,
  25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27 * GNU General Public License for more details.
  28 *
  29 * You should have received a copy of the GNU General Public License
  30 * along with this program; if not, write to the Free Software
  31 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  32 */
  33
  34
  35#include <linux/module.h>
  36#include <linux/init.h>
  37#include <linux/slab.h>
  38#include <linux/jiffies.h>
  39#include <linux/i2c.h>
  40#include <linux/hwmon.h>
  41#include <linux/hwmon-sysfs.h>
  42#include <linux/err.h>
  43#include <linux/mutex.h>
  44#include <linux/sysfs.h>
  45
  46static const unsigned short normal_i2c[] = {
  47        0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  48
  49/*
  50 * The MAX6642 registers
  51 */
  52
  53#define MAX6642_REG_R_MAN_ID            0xFE
  54#define MAX6642_REG_R_CONFIG            0x03
  55#define MAX6642_REG_W_CONFIG            0x09
  56#define MAX6642_REG_R_STATUS            0x02
  57#define MAX6642_REG_R_LOCAL_TEMP        0x00
  58#define MAX6642_REG_R_LOCAL_TEMPL       0x11
  59#define MAX6642_REG_R_LOCAL_HIGH        0x05
  60#define MAX6642_REG_W_LOCAL_HIGH        0x0B
  61#define MAX6642_REG_R_REMOTE_TEMP       0x01
  62#define MAX6642_REG_R_REMOTE_TEMPL      0x10
  63#define MAX6642_REG_R_REMOTE_HIGH       0x07
  64#define MAX6642_REG_W_REMOTE_HIGH       0x0D
  65
  66/*
  67 * Conversions
  68 */
  69
  70static int temp_from_reg10(int val)
  71{
  72        return val * 250;
  73}
  74
  75static int temp_from_reg(int val)
  76{
  77        return val * 1000;
  78}
  79
  80static int temp_to_reg(int val)
  81{
  82        return val / 1000;
  83}
  84
  85/*
  86 * Client data (each client gets its own)
  87 */
  88
  89struct max6642_data {
  90        struct device *hwmon_dev;
  91        struct mutex update_lock;
  92        bool valid; /* zero until following fields are valid */
  93        unsigned long last_updated; /* in jiffies */
  94
  95        /* registers values */
  96        u16 temp_input[2]; /* local/remote */
  97        u16 temp_high[2]; /* local/remote */
  98        u8 alarms;
  99};
 100
 101/*
 102 * Real code
 103 */
 104
 105static void max6642_init_client(struct i2c_client *client)
 106{
 107        u8 config;
 108        struct max6642_data *data = i2c_get_clientdata(client);
 109
 110        /*
 111         * Start the conversions.
 112         */
 113        config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
 114        if (config & 0x40)
 115                i2c_smbus_write_byte_data(client, MAX6642_REG_W_CONFIG,
 116                                          config & 0xBF); /* run */
 117
 118        data->temp_high[0] = i2c_smbus_read_byte_data(client,
 119                                MAX6642_REG_R_LOCAL_HIGH);
 120        data->temp_high[1] = i2c_smbus_read_byte_data(client,
 121                                MAX6642_REG_R_REMOTE_HIGH);
 122}
 123
 124/* Return 0 if detection is successful, -ENODEV otherwise */
 125static int max6642_detect(struct i2c_client *client,
 126                          struct i2c_board_info *info)
 127{
 128        struct i2c_adapter *adapter = client->adapter;
 129        u8 reg_config, reg_status, man_id;
 130
 131        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 132                return -ENODEV;
 133
 134        /* identification */
 135        man_id = i2c_smbus_read_byte_data(client, MAX6642_REG_R_MAN_ID);
 136        if (man_id != 0x4D)
 137                return -ENODEV;
 138
 139        /* sanity check */
 140        if (i2c_smbus_read_byte_data(client, 0x04) != 0x4D
 141            || i2c_smbus_read_byte_data(client, 0x06) != 0x4D
 142            || i2c_smbus_read_byte_data(client, 0xff) != 0x4D)
 143                return -ENODEV;
 144
 145        /*
 146         * We read the config and status register, the 4 lower bits in the
 147         * config register should be zero and bit 5, 3, 1 and 0 should be
 148         * zero in the status register.
 149         */
 150        reg_config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
 151        if ((reg_config & 0x0f) != 0x00)
 152                return -ENODEV;
 153
 154        /* in between, another round of sanity checks */
 155        if (i2c_smbus_read_byte_data(client, 0x04) != reg_config
 156            || i2c_smbus_read_byte_data(client, 0x06) != reg_config
 157            || i2c_smbus_read_byte_data(client, 0xff) != reg_config)
 158                return -ENODEV;
 159
 160        reg_status = i2c_smbus_read_byte_data(client, MAX6642_REG_R_STATUS);
 161        if ((reg_status & 0x2b) != 0x00)
 162                return -ENODEV;
 163
 164        strlcpy(info->type, "max6642", I2C_NAME_SIZE);
 165
 166        return 0;
 167}
 168
 169static struct max6642_data *max6642_update_device(struct device *dev)
 170{
 171        struct i2c_client *client = to_i2c_client(dev);
 172        struct max6642_data *data = i2c_get_clientdata(client);
 173        u16 val, tmp;
 174
 175        mutex_lock(&data->update_lock);
 176
 177        if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
 178                dev_dbg(&client->dev, "Updating max6642 data.\n");
 179                val = i2c_smbus_read_byte_data(client,
 180                                        MAX6642_REG_R_LOCAL_TEMPL);
 181                tmp = (val >> 6) & 3;
 182                val = i2c_smbus_read_byte_data(client,
 183                                        MAX6642_REG_R_LOCAL_TEMP);
 184                val = (val << 2) | tmp;
 185                data->temp_input[0] = val;
 186                val = i2c_smbus_read_byte_data(client,
 187                                        MAX6642_REG_R_REMOTE_TEMPL);
 188                tmp = (val >> 6) & 3;
 189                val = i2c_smbus_read_byte_data(client,
 190                                        MAX6642_REG_R_REMOTE_TEMP);
 191                val = (val << 2) | tmp;
 192                data->temp_input[1] = val;
 193                data->alarms = i2c_smbus_read_byte_data(client,
 194                                        MAX6642_REG_R_STATUS);
 195
 196                data->last_updated = jiffies;
 197                data->valid = 1;
 198        }
 199
 200        mutex_unlock(&data->update_lock);
 201
 202        return data;
 203}
 204
 205/*
 206 * Sysfs stuff
 207 */
 208
 209static ssize_t show_temp_max10(struct device *dev,
 210                               struct device_attribute *dev_attr, char *buf)
 211{
 212        struct max6642_data *data = max6642_update_device(dev);
 213        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 214
 215        return sprintf(buf, "%d\n",
 216                       temp_from_reg10(data->temp_input[attr->index]));
 217}
 218
 219static ssize_t show_temp_max(struct device *dev, struct device_attribute *attr,
 220                             char *buf)
 221{
 222        struct max6642_data *data = max6642_update_device(dev);
 223        struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
 224
 225        return sprintf(buf, "%d\n", temp_from_reg(data->temp_high[attr2->nr]));
 226}
 227
 228static ssize_t set_temp_max(struct device *dev, struct device_attribute *attr,
 229                            const char *buf, size_t count)
 230{
 231        unsigned long val;
 232        int err;
 233        struct i2c_client *client = to_i2c_client(dev);
 234        struct max6642_data *data = i2c_get_clientdata(client);
 235        struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
 236
 237        err = kstrtoul(buf, 10, &val);
 238        if (err < 0)
 239                return err;
 240
 241        mutex_lock(&data->update_lock);
 242        data->temp_high[attr2->nr] = SENSORS_LIMIT(temp_to_reg(val), 0, 255);
 243        i2c_smbus_write_byte_data(client, attr2->index,
 244                                  data->temp_high[attr2->nr]);
 245        mutex_unlock(&data->update_lock);
 246        return count;
 247}
 248
 249static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 250                          char *buf)
 251{
 252        int bitnr = to_sensor_dev_attr(attr)->index;
 253        struct max6642_data *data = max6642_update_device(dev);
 254        return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
 255}
 256
 257static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_max10, NULL, 0);
 258static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_max10, NULL, 1);
 259static SENSOR_DEVICE_ATTR_2(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
 260                            set_temp_max, 0, MAX6642_REG_W_LOCAL_HIGH);
 261static SENSOR_DEVICE_ATTR_2(temp2_max, S_IWUSR | S_IRUGO, show_temp_max,
 262                            set_temp_max, 1, MAX6642_REG_W_REMOTE_HIGH);
 263static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 2);
 264static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
 265static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 4);
 266
 267static struct attribute *max6642_attributes[] = {
 268        &sensor_dev_attr_temp1_input.dev_attr.attr,
 269        &sensor_dev_attr_temp2_input.dev_attr.attr,
 270        &sensor_dev_attr_temp1_max.dev_attr.attr,
 271        &sensor_dev_attr_temp2_max.dev_attr.attr,
 272
 273        &sensor_dev_attr_temp2_fault.dev_attr.attr,
 274        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 275        &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
 276        NULL
 277};
 278
 279static const struct attribute_group max6642_group = {
 280        .attrs = max6642_attributes,
 281};
 282
 283static int max6642_probe(struct i2c_client *new_client,
 284                         const struct i2c_device_id *id)
 285{
 286        struct max6642_data *data;
 287        int err;
 288
 289        data = devm_kzalloc(&new_client->dev, sizeof(struct max6642_data),
 290                            GFP_KERNEL);
 291        if (!data)
 292                return -ENOMEM;
 293
 294        i2c_set_clientdata(new_client, data);
 295        mutex_init(&data->update_lock);
 296
 297        /* Initialize the MAX6642 chip */
 298        max6642_init_client(new_client);
 299
 300        /* Register sysfs hooks */
 301        err = sysfs_create_group(&new_client->dev.kobj, &max6642_group);
 302        if (err)
 303                return err;
 304
 305        data->hwmon_dev = hwmon_device_register(&new_client->dev);
 306        if (IS_ERR(data->hwmon_dev)) {
 307                err = PTR_ERR(data->hwmon_dev);
 308                goto exit_remove_files;
 309        }
 310
 311        return 0;
 312
 313exit_remove_files:
 314        sysfs_remove_group(&new_client->dev.kobj, &max6642_group);
 315        return err;
 316}
 317
 318static int max6642_remove(struct i2c_client *client)
 319{
 320        struct max6642_data *data = i2c_get_clientdata(client);
 321
 322        hwmon_device_unregister(data->hwmon_dev);
 323        sysfs_remove_group(&client->dev.kobj, &max6642_group);
 324
 325        return 0;
 326}
 327
 328/*
 329 * Driver data (common to all clients)
 330 */
 331
 332static const struct i2c_device_id max6642_id[] = {
 333        { "max6642", 0 },
 334        { }
 335};
 336MODULE_DEVICE_TABLE(i2c, max6642_id);
 337
 338static struct i2c_driver max6642_driver = {
 339        .class          = I2C_CLASS_HWMON,
 340        .driver = {
 341                .name   = "max6642",
 342        },
 343        .probe          = max6642_probe,
 344        .remove         = max6642_remove,
 345        .id_table       = max6642_id,
 346        .detect         = max6642_detect,
 347        .address_list   = normal_i2c,
 348};
 349
 350module_i2c_driver(max6642_driver);
 351
 352MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
 353MODULE_DESCRIPTION("MAX6642 sensor driver");
 354MODULE_LICENSE("GPL");
 355
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