drivers/hwmon/w83l785ts.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware
   4  *               monitoring
   5  * Copyright (C) 2003-2009  Jean Delvare <jdelvare@suse.de>
   6  *
   7  * Inspired from the lm83 driver. The W83L785TS-S is a sensor chip made
   8  * by Winbond. It reports a single external temperature with a 1 deg
   9  * resolution and a 3 deg accuracy. Datasheet can be obtained from
  10  * Winbond's website at:
  11  *   http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83L785TS-S.pdf
  12  *
  13  * Ported to Linux 2.6 by Wolfgang Ziegler <nuppla@gmx.at> and Jean Delvare
  14  * <jdelvare@suse.de>.
  15  *
  16  * Thanks to James Bolt <james@evilpenguin.com> for benchmarking the read
  17  * error handling mechanism.
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/delay.h>
  22 #include <linux/init.h>
  23 #include <linux/slab.h>
  24 #include <linux/jiffies.h>
  25 #include <linux/i2c.h>
  26 #include <linux/hwmon.h>
  27 #include <linux/hwmon-sysfs.h>
  28 #include <linux/err.h>
  29 #include <linux/mutex.h>
  30
  31 /* How many retries on register read error */
  32 #define MAX_RETRIES     5
  33
  34 /*
  35  * Address to scan
  36  * Address is fully defined internally and cannot be changed.
  37  */
  38
  39 static const unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };
  40
  41 /*
  42  * The W83L785TS-S registers
  43  * Manufacturer ID is 0x5CA3 for Winbond.
  44  */
  45
  46 #define W83L785TS_REG_MAN_ID1           0x4D
  47 #define W83L785TS_REG_MAN_ID2           0x4C
  48 #define W83L785TS_REG_CHIP_ID           0x4E
  49 #define W83L785TS_REG_CONFIG            0x40
  50 #define W83L785TS_REG_TYPE              0x52
  51 #define W83L785TS_REG_TEMP              0x27
  52 #define W83L785TS_REG_TEMP_OVER         0x53 /* not sure about this one */
  53
  54 /*
  55  * Conversions
  56  * The W83L785TS-S uses signed 8-bit values.
  57  */
  58
  59 #define TEMP_FROM_REG(val)      ((val) * 1000)
  60
  61 /*
  62  * Functions declaration
  63  */
  64
  65 static int w83l785ts_probe(struct i2c_client *client);
  66 static int w83l785ts_detect(struct i2c_client *client,
  67                             struct i2c_board_info *info);
  68 static int w83l785ts_remove(struct i2c_client *client);
  69 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
  70 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
  71
  72 /*
  73  * Driver data (common to all clients)
  74  */
  75
  76 static const struct i2c_device_id w83l785ts_id[] = {
  77         { "w83l785ts", 0 },
  78         { }
  79 };
  80 MODULE_DEVICE_TABLE(i2c, w83l785ts_id);
  81
  82 static struct i2c_driver w83l785ts_driver = {
  83         .class          = I2C_CLASS_HWMON,
  84         .driver = {
  85                 .name   = "w83l785ts",
  86         },
  87         .probe_new      = w83l785ts_probe,
  88         .remove         = w83l785ts_remove,
  89         .id_table       = w83l785ts_id,
  90         .detect         = w83l785ts_detect,
  91         .address_list   = normal_i2c,
  92 };
  93
  94 /*
  95  * Client data (each client gets its own)
  96  */
  97
  98 struct w83l785ts_data {
  99         struct device *hwmon_dev;
 100         struct mutex update_lock;
 101         char valid; /* zero until following fields are valid */
 102         unsigned long last_updated; /* in jiffies */
 103
 104         /* registers values */
 105         s8 temp[2]; /* 0: input, 1: critical limit */
 106 };
 107
 108 /*
 109  * Sysfs stuff
 110  */
 111
 112 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
 113         char *buf)
 114 {
 115         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 116         struct w83l785ts_data *data = w83l785ts_update_device(dev);
 117         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
 118 }
 119
 120 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 121 static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
 122
 123 /*
 124  * Real code
 125  */
 126
 127 /* Return 0 if detection is successful, -ENODEV otherwise */
 128 static int w83l785ts_detect(struct i2c_client *client,
 129                             struct i2c_board_info *info)
 130 {
 131         struct i2c_adapter *adapter = client->adapter;
 132         u16 man_id;
 133         u8 chip_id;
 134
 135         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 136                 return -ENODEV;
 137
 138         /* detection */
 139         if ((w83l785ts_read_value(client, W83L785TS_REG_CONFIG, 0) & 0x80)
 140          || (w83l785ts_read_value(client, W83L785TS_REG_TYPE, 0) & 0xFC)) {
 141                 dev_dbg(&adapter->dev,
 142                         "W83L785TS-S detection failed at 0x%02x\n",
 143                         client->addr);
 144                 return -ENODEV;
 145         }
 146
 147         /* Identification */
 148         man_id = (w83l785ts_read_value(client, W83L785TS_REG_MAN_ID1, 0) << 8)
 149                + w83l785ts_read_value(client, W83L785TS_REG_MAN_ID2, 0);
 150         chip_id = w83l785ts_read_value(client, W83L785TS_REG_CHIP_ID, 0);
 151
 152         if (man_id != 0x5CA3            /* Winbond */
 153          || chip_id != 0x70) {          /* W83L785TS-S */
 154                 dev_dbg(&adapter->dev,
 155                         "Unsupported chip (man_id=0x%04X, chip_id=0x%02X)\n",
 156                         man_id, chip_id);
 157                 return -ENODEV;
 158         }
 159
 160         strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);
 161
 162         return 0;
 163 }
 164
 165 static int w83l785ts_probe(struct i2c_client *client)
 166 {
 167         struct w83l785ts_data *data;
 168         struct device *dev = &client->dev;
 169         int err;
 170
 171         data = devm_kzalloc(dev, sizeof(struct w83l785ts_data), GFP_KERNEL);
 172         if (!data)
 173                 return -ENOMEM;
 174
 175         i2c_set_clientdata(client, data);
 176         mutex_init(&data->update_lock);
 177
 178         /*
 179          * Initialize the W83L785TS chip
 180          * Nothing yet, assume it is already started.
 181          */
 182
 183         err = device_create_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
 184         if (err)
 185                 return err;
 186
 187         err = device_create_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
 188         if (err)
 189                 goto exit_remove;
 190
 191         /* Register sysfs hooks */
 192         data->hwmon_dev = hwmon_device_register(dev);
 193         if (IS_ERR(data->hwmon_dev)) {
 194                 err = PTR_ERR(data->hwmon_dev);
 195                 goto exit_remove;
 196         }
 197
 198         return 0;
 199
 200 exit_remove:
 201         device_remove_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
 202         device_remove_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
 203         return err;
 204 }
 205
 206 static int w83l785ts_remove(struct i2c_client *client)
 207 {
 208         struct w83l785ts_data *data = i2c_get_clientdata(client);
 209
 210         hwmon_device_unregister(data->hwmon_dev);
 211         device_remove_file(&client->dev,
 212                            &sensor_dev_attr_temp1_input.dev_attr);
 213         device_remove_file(&client->dev,
 214                            &sensor_dev_attr_temp1_max.dev_attr);
 215
 216         return 0;
 217 }
 218
 219 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
 220 {
 221         int value, i;
 222         struct device *dev;
 223         const char *prefix;
 224
 225         /*
 226          * We might be called during detection, at which point the client
 227          * isn't yet fully initialized, so we can't use dev_dbg on it
 228          */
 229         if (i2c_get_clientdata(client)) {
 230                 dev = &client->dev;
 231                 prefix = "";
 232         } else {
 233                 dev = &client->adapter->dev;
 234                 prefix = "w83l785ts: ";
 235         }
 236
 237         /*
 238          * Frequent read errors have been reported on Asus boards, so we
 239          * retry on read errors. If it still fails (unlikely), return the
 240          * default value requested by the caller.
 241          */
 242         for (i = 1; i <= MAX_RETRIES; i++) {
 243                 value = i2c_smbus_read_byte_data(client, reg);
 244                 if (value >= 0) {
 245                         dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
 246                                 prefix, value, reg);
 247                         return value;
 248                 }
 249                 dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
 250                 msleep(i);
 251         }
 252
 253         dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
 254                 reg);
 255         return defval;
 256 }
 257
 258 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
 259 {
 260         struct i2c_client *client = to_i2c_client(dev);
 261         struct w83l785ts_data *data = i2c_get_clientdata(client);
 262
 263         mutex_lock(&data->update_lock);
 264
 265         if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
 266                 dev_dbg(&client->dev, "Updating w83l785ts data.\n");
 267                 data->temp[0] = w83l785ts_read_value(client,
 268                                 W83L785TS_REG_TEMP, data->temp[0]);
 269                 data->temp[1] = w83l785ts_read_value(client,
 270                                 W83L785TS_REG_TEMP_OVER, data->temp[1]);
 271
 272                 data->last_updated = jiffies;
 273                 data->valid = 1;
 274         }
 275
 276         mutex_unlock(&data->update_lock);
 277
 278         return data;
 279 }
 280
 281 module_i2c_driver(w83l785ts_driver);
 282
 283 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
 284 MODULE_DESCRIPTION("W83L785TS-S driver");
 285 MODULE_LICENSE("GPL");