drivers/hwmon/max6642.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Driver for +/-1 degree C, SMBus-Compatible Remote/Local Temperature Sensor
   4  * with Overtemperature Alarm
   5  *
   6  * Copyright (C) 2011 AppearTV AS
   7  *
   8  * Derived from:
   9  *
  10  *  Based on the max1619 driver.
  11  *  Copyright (C) 2003-2004 Oleksij Rempel <bug-track@fisher-privat.net>
  12  *                          Jean Delvare <jdelvare@suse.de>
  13  *
  14  * The MAX6642 is a sensor chip made by Maxim.
  15  * It reports up to two temperatures (its own plus up to
  16  * one external one). Complete datasheet can be
  17  * obtained from Maxim's website at:
  18  *   http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf
  19  */
  20
  21
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/slab.h>
  25 #include <linux/jiffies.h>
  26 #include <linux/i2c.h>
  27 #include <linux/hwmon.h>
  28 #include <linux/hwmon-sysfs.h>
  29 #include <linux/err.h>
  30 #include <linux/mutex.h>
  31 #include <linux/sysfs.h>
  32
  33 static const unsigned short normal_i2c[] = {
  34         0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  35
  36 /*
  37  * The MAX6642 registers
  38  */
  39
  40 #define MAX6642_REG_R_MAN_ID            0xFE
  41 #define MAX6642_REG_R_CONFIG            0x03
  42 #define MAX6642_REG_W_CONFIG            0x09
  43 #define MAX6642_REG_R_STATUS            0x02
  44 #define MAX6642_REG_R_LOCAL_TEMP        0x00
  45 #define MAX6642_REG_R_LOCAL_TEMPL       0x11
  46 #define MAX6642_REG_R_LOCAL_HIGH        0x05
  47 #define MAX6642_REG_W_LOCAL_HIGH        0x0B
  48 #define MAX6642_REG_R_REMOTE_TEMP       0x01
  49 #define MAX6642_REG_R_REMOTE_TEMPL      0x10
  50 #define MAX6642_REG_R_REMOTE_HIGH       0x07
  51 #define MAX6642_REG_W_REMOTE_HIGH       0x0D
  52
  53 /*
  54  * Conversions
  55  */
  56
  57 static int temp_from_reg10(int val)
  58 {
  59         return val * 250;
  60 }
  61
  62 static int temp_from_reg(int val)
  63 {
  64         return val * 1000;
  65 }
  66
  67 static int temp_to_reg(int val)
  68 {
  69         return val / 1000;
  70 }
  71
  72 /*
  73  * Client data (each client gets its own)
  74  */
  75
  76 struct max6642_data {
  77         struct i2c_client *client;
  78         struct mutex update_lock;
  79         bool valid; /* zero until following fields are valid */
  80         unsigned long last_updated; /* in jiffies */
  81
  82         /* registers values */
  83         u16 temp_input[2]; /* local/remote */
  84         u16 temp_high[2]; /* local/remote */
  85         u8 alarms;
  86 };
  87
  88 /*
  89  * Real code
  90  */
  91
  92 static void max6642_init_client(struct max6642_data *data,
  93                                 struct i2c_client *client)
  94 {
  95         u8 config;
  96
  97         /*
  98          * Start the conversions.
  99          */
 100         config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
 101         if (config & 0x40)
 102                 i2c_smbus_write_byte_data(client, MAX6642_REG_W_CONFIG,
 103                                           config & 0xBF); /* run */
 104
 105         data->temp_high[0] = i2c_smbus_read_byte_data(client,
 106                                 MAX6642_REG_R_LOCAL_HIGH);
 107         data->temp_high[1] = i2c_smbus_read_byte_data(client,
 108                                 MAX6642_REG_R_REMOTE_HIGH);
 109 }
 110
 111 /* Return 0 if detection is successful, -ENODEV otherwise */
 112 static int max6642_detect(struct i2c_client *client,
 113                           struct i2c_board_info *info)
 114 {
 115         struct i2c_adapter *adapter = client->adapter;
 116         u8 reg_config, reg_status, man_id;
 117
 118         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 119                 return -ENODEV;
 120
 121         /* identification */
 122         man_id = i2c_smbus_read_byte_data(client, MAX6642_REG_R_MAN_ID);
 123         if (man_id != 0x4D)
 124                 return -ENODEV;
 125
 126         /* sanity check */
 127         if (i2c_smbus_read_byte_data(client, 0x04) != 0x4D
 128             || i2c_smbus_read_byte_data(client, 0x06) != 0x4D
 129             || i2c_smbus_read_byte_data(client, 0xff) != 0x4D)
 130                 return -ENODEV;
 131
 132         /*
 133          * We read the config and status register, the 4 lower bits in the
 134          * config register should be zero and bit 5, 3, 1 and 0 should be
 135          * zero in the status register.
 136          */
 137         reg_config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
 138         if ((reg_config & 0x0f) != 0x00)
 139                 return -ENODEV;
 140
 141         /* in between, another round of sanity checks */
 142         if (i2c_smbus_read_byte_data(client, 0x04) != reg_config
 143             || i2c_smbus_read_byte_data(client, 0x06) != reg_config
 144             || i2c_smbus_read_byte_data(client, 0xff) != reg_config)
 145                 return -ENODEV;
 146
 147         reg_status = i2c_smbus_read_byte_data(client, MAX6642_REG_R_STATUS);
 148         if ((reg_status & 0x2b) != 0x00)
 149                 return -ENODEV;
 150
 151         strlcpy(info->type, "max6642", I2C_NAME_SIZE);
 152
 153         return 0;
 154 }
 155
 156 static struct max6642_data *max6642_update_device(struct device *dev)
 157 {
 158         struct max6642_data *data = dev_get_drvdata(dev);
 159         struct i2c_client *client = data->client;
 160         u16 val, tmp;
 161
 162         mutex_lock(&data->update_lock);
 163
 164         if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
 165                 dev_dbg(dev, "Updating max6642 data.\n");
 166                 val = i2c_smbus_read_byte_data(client,
 167                                         MAX6642_REG_R_LOCAL_TEMPL);
 168                 tmp = (val >> 6) & 3;
 169                 val = i2c_smbus_read_byte_data(client,
 170                                         MAX6642_REG_R_LOCAL_TEMP);
 171                 val = (val << 2) | tmp;
 172                 data->temp_input[0] = val;
 173                 val = i2c_smbus_read_byte_data(client,
 174                                         MAX6642_REG_R_REMOTE_TEMPL);
 175                 tmp = (val >> 6) & 3;
 176                 val = i2c_smbus_read_byte_data(client,
 177                                         MAX6642_REG_R_REMOTE_TEMP);
 178                 val = (val << 2) | tmp;
 179                 data->temp_input[1] = val;
 180                 data->alarms = i2c_smbus_read_byte_data(client,
 181                                         MAX6642_REG_R_STATUS);
 182
 183                 data->last_updated = jiffies;
 184                 data->valid = 1;
 185         }
 186
 187         mutex_unlock(&data->update_lock);
 188
 189         return data;
 190 }
 191
 192 /*
 193  * Sysfs stuff
 194  */
 195
 196 static ssize_t temp_max10_show(struct device *dev,
 197                                struct device_attribute *dev_attr, char *buf)
 198 {
 199         struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
 200         struct max6642_data *data = max6642_update_device(dev);
 201
 202         return sprintf(buf, "%d\n",
 203                        temp_from_reg10(data->temp_input[attr->index]));
 204 }
 205
 206 static ssize_t temp_max_show(struct device *dev,
 207                              struct device_attribute *attr, char *buf)
 208 {
 209         struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
 210         struct max6642_data *data = max6642_update_device(dev);
 211
 212         return sprintf(buf, "%d\n", temp_from_reg(data->temp_high[attr2->nr]));
 213 }
 214
 215 static ssize_t temp_max_store(struct device *dev,
 216                               struct device_attribute *attr, const char *buf,
 217                               size_t count)
 218 {
 219         struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
 220         struct max6642_data *data = dev_get_drvdata(dev);
 221         unsigned long val;
 222         int err;
 223
 224         err = kstrtoul(buf, 10, &val);
 225         if (err < 0)
 226                 return err;
 227
 228         mutex_lock(&data->update_lock);
 229         data->temp_high[attr2->nr] = clamp_val(temp_to_reg(val), 0, 255);
 230         i2c_smbus_write_byte_data(data->client, attr2->index,
 231                                   data->temp_high[attr2->nr]);
 232         mutex_unlock(&data->update_lock);
 233         return count;
 234 }
 235
 236 static ssize_t alarm_show(struct device *dev, struct device_attribute *attr,
 237                           char *buf)
 238 {
 239         int bitnr = to_sensor_dev_attr(attr)->index;
 240         struct max6642_data *data = max6642_update_device(dev);
 241         return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
 242 }
 243
 244 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_max10, 0);
 245 static SENSOR_DEVICE_ATTR_RO(temp2_input, temp_max10, 1);
 246 static SENSOR_DEVICE_ATTR_2_RW(temp1_max, temp_max, 0,
 247                                MAX6642_REG_W_LOCAL_HIGH);
 248 static SENSOR_DEVICE_ATTR_2_RW(temp2_max, temp_max, 1,
 249                                MAX6642_REG_W_REMOTE_HIGH);
 250 static SENSOR_DEVICE_ATTR_RO(temp2_fault, alarm, 2);
 251 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 6);
 252 static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, alarm, 4);
 253
 254 static struct attribute *max6642_attrs[] = {
 255         &sensor_dev_attr_temp1_input.dev_attr.attr,
 256         &sensor_dev_attr_temp2_input.dev_attr.attr,
 257         &sensor_dev_attr_temp1_max.dev_attr.attr,
 258         &sensor_dev_attr_temp2_max.dev_attr.attr,
 259
 260         &sensor_dev_attr_temp2_fault.dev_attr.attr,
 261         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 262         &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
 263         NULL
 264 };
 265 ATTRIBUTE_GROUPS(max6642);
 266
 267 static int max6642_probe(struct i2c_client *client,
 268                          const struct i2c_device_id *id)
 269 {
 270         struct device *dev = &client->dev;
 271         struct max6642_data *data;
 272         struct device *hwmon_dev;
 273
 274         data = devm_kzalloc(dev, sizeof(struct max6642_data), GFP_KERNEL);
 275         if (!data)
 276                 return -ENOMEM;
 277
 278         data->client = client;
 279         mutex_init(&data->update_lock);
 280
 281         /* Initialize the MAX6642 chip */
 282         max6642_init_client(data, client);
 283
 284         hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
 285                                                            client->name, data,
 286                                                            max6642_groups);
 287         return PTR_ERR_OR_ZERO(hwmon_dev);
 288 }
 289
 290 /*
 291  * Driver data (common to all clients)
 292  */
 293
 294 static const struct i2c_device_id max6642_id[] = {
 295         { "max6642", 0 },
 296         { }
 297 };
 298 MODULE_DEVICE_TABLE(i2c, max6642_id);
 299
 300 static struct i2c_driver max6642_driver = {
 301         .class          = I2C_CLASS_HWMON,
 302         .driver = {
 303                 .name   = "max6642",
 304         },
 305         .probe          = max6642_probe,
 306         .id_table       = max6642_id,
 307         .detect         = max6642_detect,
 308         .address_list   = normal_i2c,
 309 };
 310
 311 module_i2c_driver(max6642_driver);
 312
 313 MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
 314 MODULE_DESCRIPTION("MAX6642 sensor driver");
 315 MODULE_LICENSE("GPL");