linux/drivers/hwmon/w83l785ts.c
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   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
  39static 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
  65static int w83l785ts_probe(struct i2c_client *client);
  66static int w83l785ts_detect(struct i2c_client *client,
  67                            struct i2c_board_info *info);
  68static int w83l785ts_remove(struct i2c_client *client);
  69static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
  70static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
  71
  72/*
  73 * Driver data (common to all clients)
  74 */
  75
  76static const struct i2c_device_id w83l785ts_id[] = {
  77        { "w83l785ts", 0 },
  78        { }
  79};
  80MODULE_DEVICE_TABLE(i2c, w83l785ts_id);
  81
  82static 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
  98struct w83l785ts_data {
  99        struct device *hwmon_dev;
 100        struct mutex update_lock;
 101        bool valid; /* false 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
 112static 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
 120static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 121static 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 */
 128static 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
 165static 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
 200exit_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
 206static 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
 219static 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
 258static 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 = true;
 274        }
 275
 276        mutex_unlock(&data->update_lock);
 277
 278        return data;
 279}
 280
 281module_i2c_driver(w83l785ts_driver);
 282
 283MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
 284MODULE_DESCRIPTION("W83L785TS-S driver");
 285MODULE_LICENSE("GPL");
 286