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                            const struct i2c_device_id *id);
  67 static int w83l785ts_detect(struct i2c_client *client,
  68                             struct i2c_board_info *info);
  69 static int w83l785ts_remove(struct i2c_client *client);
  70 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
  71 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
  72
  73 /*
  74  * Driver data (common to all clients)
  75  */
  76
  77 static const struct i2c_device_id w83l785ts_id[] = {
  78         { "w83l785ts", 0 },
  79         { }
  80 };
  81 MODULE_DEVICE_TABLE(i2c, w83l785ts_id);
  82
  83 static struct i2c_driver w83l785ts_driver = {
  84         .class          = I2C_CLASS_HWMON,
  85         .driver = {
  86                 .name   = "w83l785ts",
  87         },
  88         .probe          = w83l785ts_probe,
  89         .remove         = w83l785ts_remove,
  90         .id_table       = w83l785ts_id,
  91         .detect         = w83l785ts_detect,
  92         .address_list   = normal_i2c,
  93 };
  94
  95 /*
  96  * Client data (each client gets its own)
  97  */
  98
  99 struct w83l785ts_data {
 100         struct device *hwmon_dev;
 101         struct mutex update_lock;
 102         char valid; /* zero until following fields are valid */
 103         unsigned long last_updated; /* in jiffies */
 104
 105         /* registers values */
 106         s8 temp[2]; /* 0: input, 1: critical limit */
 107 };
 108
 109 /*
 110  * Sysfs stuff
 111  */
 112
 113 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
 114         char *buf)
 115 {
 116         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 117         struct w83l785ts_data *data = w83l785ts_update_device(dev);
 118         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
 119 }
 120
 121 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 122 static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
 123
 124 /*
 125  * Real code
 126  */
 127
 128 /* Return 0 if detection is successful, -ENODEV otherwise */
 129 static int w83l785ts_detect(struct i2c_client *client,
 130                             struct i2c_board_info *info)
 131 {
 132         struct i2c_adapter *adapter = client->adapter;
 133         u16 man_id;
 134         u8 chip_id;
 135
 136         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 137                 return -ENODEV;
 138
 139         /* detection */
 140         if ((w83l785ts_read_value(client, W83L785TS_REG_CONFIG, 0) & 0x80)
 141          || (w83l785ts_read_value(client, W83L785TS_REG_TYPE, 0) & 0xFC)) {
 142                 dev_dbg(&adapter->dev,
 143                         "W83L785TS-S detection failed at 0x%02x\n",
 144                         client->addr);
 145                 return -ENODEV;
 146         }
 147
 148         /* Identification */
 149         man_id = (w83l785ts_read_value(client, W83L785TS_REG_MAN_ID1, 0) << 8)
 150                + w83l785ts_read_value(client, W83L785TS_REG_MAN_ID2, 0);
 151         chip_id = w83l785ts_read_value(client, W83L785TS_REG_CHIP_ID, 0);
 152
 153         if (man_id != 0x5CA3            /* Winbond */
 154          || chip_id != 0x70) {          /* W83L785TS-S */
 155                 dev_dbg(&adapter->dev,
 156                         "Unsupported chip (man_id=0x%04X, chip_id=0x%02X)\n",
 157                         man_id, chip_id);
 158                 return -ENODEV;
 159         }
 160
 161         strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);
 162
 163         return 0;
 164 }
 165
 166 static int w83l785ts_probe(struct i2c_client *client,
 167                            const struct i2c_device_id *id)
 168 {
 169         struct w83l785ts_data *data;
 170         struct device *dev = &client->dev;
 171         int err;
 172
 173         data = devm_kzalloc(dev, sizeof(struct w83l785ts_data), GFP_KERNEL);
 174         if (!data)
 175                 return -ENOMEM;
 176
 177         i2c_set_clientdata(client, data);
 178         mutex_init(&data->update_lock);
 179
 180         /*
 181          * Initialize the W83L785TS chip
 182          * Nothing yet, assume it is already started.
 183          */
 184
 185         err = device_create_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
 186         if (err)
 187                 return err;
 188
 189         err = device_create_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
 190         if (err)
 191                 goto exit_remove;
 192
 193         /* Register sysfs hooks */
 194         data->hwmon_dev = hwmon_device_register(dev);
 195         if (IS_ERR(data->hwmon_dev)) {
 196                 err = PTR_ERR(data->hwmon_dev);
 197                 goto exit_remove;
 198         }
 199
 200         return 0;
 201
 202 exit_remove:
 203         device_remove_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
 204         device_remove_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
 205         return err;
 206 }
 207
 208 static int w83l785ts_remove(struct i2c_client *client)
 209 {
 210         struct w83l785ts_data *data = i2c_get_clientdata(client);
 211
 212         hwmon_device_unregister(data->hwmon_dev);
 213         device_remove_file(&client->dev,
 214                            &sensor_dev_attr_temp1_input.dev_attr);
 215         device_remove_file(&client->dev,
 216                            &sensor_dev_attr_temp1_max.dev_attr);
 217
 218         return 0;
 219 }
 220
 221 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
 222 {
 223         int value, i;
 224         struct device *dev;
 225         const char *prefix;
 226
 227         /*
 228          * We might be called during detection, at which point the client
 229          * isn't yet fully initialized, so we can't use dev_dbg on it
 230          */
 231         if (i2c_get_clientdata(client)) {
 232                 dev = &client->dev;
 233                 prefix = "";
 234         } else {
 235                 dev = &client->adapter->dev;
 236                 prefix = "w83l785ts: ";
 237         }
 238
 239         /*
 240          * Frequent read errors have been reported on Asus boards, so we
 241          * retry on read errors. If it still fails (unlikely), return the
 242          * default value requested by the caller.
 243          */
 244         for (i = 1; i <= MAX_RETRIES; i++) {
 245                 value = i2c_smbus_read_byte_data(client, reg);
 246                 if (value >= 0) {
 247                         dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
 248                                 prefix, value, reg);
 249                         return value;
 250                 }
 251                 dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
 252                 msleep(i);
 253         }
 254
 255         dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
 256                 reg);
 257         return defval;
 258 }
 259
 260 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
 261 {
 262         struct i2c_client *client = to_i2c_client(dev);
 263         struct w83l785ts_data *data = i2c_get_clientdata(client);
 264
 265         mutex_lock(&data->update_lock);
 266
 267         if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
 268                 dev_dbg(&client->dev, "Updating w83l785ts data.\n");
 269                 data->temp[0] = w83l785ts_read_value(client,
 270                                 W83L785TS_REG_TEMP, data->temp[0]);
 271                 data->temp[1] = w83l785ts_read_value(client,
 272                                 W83L785TS_REG_TEMP_OVER, data->temp[1]);
 273
 274                 data->last_updated = jiffies;
 275                 data->valid = 1;
 276         }
 277
 278         mutex_unlock(&data->update_lock);
 279
 280         return data;
 281 }
 282
 283 module_i2c_driver(w83l785ts_driver);
 284
 285 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
 286 MODULE_DESCRIPTION("W83L785TS-S driver");
 287 MODULE_LICENSE("GPL");