drivers/hwmon/max6642.c

   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 <jdelvare@suse.de>
  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
  46 static 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
  70 static int temp_from_reg10(int val)
  71 {
  72         return val * 250;
  73 }
  74
  75 static int temp_from_reg(int val)
  76 {
  77         return val * 1000;
  78 }
  79
  80 static int temp_to_reg(int val)
  81 {
  82         return val / 1000;
  83 }
  84
  85 /*
  86  * Client data (each client gets its own)
  87  */
  88
  89 struct max6642_data {
  90         struct i2c_client *client;
  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
 105 static void max6642_init_client(struct max6642_data *data,
 106                                 struct i2c_client *client)
 107 {
 108         u8 config;
 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 */
 125 static 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
 169 static struct max6642_data *max6642_update_device(struct device *dev)
 170 {
 171         struct max6642_data *data = dev_get_drvdata(dev);
 172         struct i2c_client *client = data->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(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
 209 static ssize_t show_temp_max10(struct device *dev,
 210                                struct device_attribute *dev_attr, char *buf)
 211 {
 212         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 213         struct max6642_data *data = max6642_update_device(dev);
 214
 215         return sprintf(buf, "%d\n",
 216                        temp_from_reg10(data->temp_input[attr->index]));
 217 }
 218
 219 static ssize_t show_temp_max(struct device *dev, struct device_attribute *attr,
 220                              char *buf)
 221 {
 222         struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
 223         struct max6642_data *data = max6642_update_device(dev);
 224
 225         return sprintf(buf, "%d\n", temp_from_reg(data->temp_high[attr2->nr]));
 226 }
 227
 228 static ssize_t set_temp_max(struct device *dev, struct device_attribute *attr,
 229                             const char *buf, size_t count)
 230 {
 231         struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
 232         struct max6642_data *data = dev_get_drvdata(dev);
 233         unsigned long val;
 234         int err;
 235
 236         err = kstrtoul(buf, 10, &val);
 237         if (err < 0)
 238                 return err;
 239
 240         mutex_lock(&data->update_lock);
 241         data->temp_high[attr2->nr] = clamp_val(temp_to_reg(val), 0, 255);
 242         i2c_smbus_write_byte_data(data->client, attr2->index,
 243                                   data->temp_high[attr2->nr]);
 244         mutex_unlock(&data->update_lock);
 245         return count;
 246 }
 247
 248 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 249                           char *buf)
 250 {
 251         int bitnr = to_sensor_dev_attr(attr)->index;
 252         struct max6642_data *data = max6642_update_device(dev);
 253         return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
 254 }
 255
 256 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_max10, NULL, 0);
 257 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_max10, NULL, 1);
 258 static SENSOR_DEVICE_ATTR_2(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
 259                             set_temp_max, 0, MAX6642_REG_W_LOCAL_HIGH);
 260 static SENSOR_DEVICE_ATTR_2(temp2_max, S_IWUSR | S_IRUGO, show_temp_max,
 261                             set_temp_max, 1, MAX6642_REG_W_REMOTE_HIGH);
 262 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 2);
 263 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
 264 static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 4);
 265
 266 static struct attribute *max6642_attrs[] = {
 267         &sensor_dev_attr_temp1_input.dev_attr.attr,
 268         &sensor_dev_attr_temp2_input.dev_attr.attr,
 269         &sensor_dev_attr_temp1_max.dev_attr.attr,
 270         &sensor_dev_attr_temp2_max.dev_attr.attr,
 271
 272         &sensor_dev_attr_temp2_fault.dev_attr.attr,
 273         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 274         &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
 275         NULL
 276 };
 277 ATTRIBUTE_GROUPS(max6642);
 278
 279 static int max6642_probe(struct i2c_client *client,
 280                          const struct i2c_device_id *id)
 281 {
 282         struct device *dev = &client->dev;
 283         struct max6642_data *data;
 284         struct device *hwmon_dev;
 285
 286         data = devm_kzalloc(dev, sizeof(struct max6642_data), GFP_KERNEL);
 287         if (!data)
 288                 return -ENOMEM;
 289
 290         data->client = client;
 291         mutex_init(&data->update_lock);
 292
 293         /* Initialize the MAX6642 chip */
 294         max6642_init_client(data, client);
 295
 296         hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
 297                                                            client->name, data,
 298                                                            max6642_groups);
 299         return PTR_ERR_OR_ZERO(hwmon_dev);
 300 }
 301
 302 /*
 303  * Driver data (common to all clients)
 304  */
 305
 306 static const struct i2c_device_id max6642_id[] = {
 307         { "max6642", 0 },
 308         { }
 309 };
 310 MODULE_DEVICE_TABLE(i2c, max6642_id);
 311
 312 static struct i2c_driver max6642_driver = {
 313         .class          = I2C_CLASS_HWMON,
 314         .driver = {
 315                 .name   = "max6642",
 316         },
 317         .probe          = max6642_probe,
 318         .id_table       = max6642_id,
 319         .detect         = max6642_detect,
 320         .address_list   = normal_i2c,
 321 };
 322
 323 module_i2c_driver(max6642_driver);
 324
 325 MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
 326 MODULE_DESCRIPTION("MAX6642 sensor driver");
 327 MODULE_LICENSE("GPL");