drivers/hwmon/ad7414.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * An hwmon driver for the Analog Devices AD7414
   4  *
   5  * Copyright 2006 Stefan Roese <sr at denx.de>, DENX Software Engineering
   6  *
   7  * Copyright (c) 2008 PIKA Technologies
   8  *   Sean MacLennan <smaclennan@pikatech.com>
   9  *
  10  * Copyright (c) 2008 Spansion Inc.
  11  *   Frank Edelhaeuser <frank.edelhaeuser at spansion.com>
  12  *   (converted to "new style" I2C driver model, removed checkpatch.pl warnings)
  13  *
  14  * Based on ad7418.c
  15  * Copyright 2006 Tower Technologies, Alessandro Zummo <a.zummo at towertech.it>
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/jiffies.h>
  20 #include <linux/i2c.h>
  21 #include <linux/hwmon.h>
  22 #include <linux/hwmon-sysfs.h>
  23 #include <linux/err.h>
  24 #include <linux/mutex.h>
  25 #include <linux/sysfs.h>
  26 #include <linux/slab.h>
  27
  28
  29 /* AD7414 registers */
  30 #define AD7414_REG_TEMP         0x00
  31 #define AD7414_REG_CONF         0x01
  32 #define AD7414_REG_T_HIGH       0x02
  33 #define AD7414_REG_T_LOW        0x03
  34
  35 static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW };
  36
  37 struct ad7414_data {
  38         struct i2c_client       *client;
  39         struct mutex            lock;   /* atomic read data updates */
  40         char                    valid;  /* !=0 if following fields are valid */
  41         unsigned long           next_update;    /* In jiffies */
  42         s16                     temp_input;     /* Register values */
  43         s8                      temps[ARRAY_SIZE(AD7414_REG_LIMIT)];
  44 };
  45
  46 /* REG: (0.25C/bit, two's complement) << 6 */
  47 static inline int ad7414_temp_from_reg(s16 reg)
  48 {
  49         /*
  50          * use integer division instead of equivalent right shift to
  51          * guarantee arithmetic shift and preserve the sign
  52          */
  53         return ((int)reg / 64) * 250;
  54 }
  55
  56 static inline int ad7414_read(struct i2c_client *client, u8 reg)
  57 {
  58         if (reg == AD7414_REG_TEMP)
  59                 return i2c_smbus_read_word_swapped(client, reg);
  60         else
  61                 return i2c_smbus_read_byte_data(client, reg);
  62 }
  63
  64 static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value)
  65 {
  66         return i2c_smbus_write_byte_data(client, reg, value);
  67 }
  68
  69 static struct ad7414_data *ad7414_update_device(struct device *dev)
  70 {
  71         struct ad7414_data *data = dev_get_drvdata(dev);
  72         struct i2c_client *client = data->client;
  73
  74         mutex_lock(&data->lock);
  75
  76         if (time_after(jiffies, data->next_update) || !data->valid) {
  77                 int value, i;
  78
  79                 dev_dbg(&client->dev, "starting ad7414 update\n");
  80
  81                 value = ad7414_read(client, AD7414_REG_TEMP);
  82                 if (value < 0)
  83                         dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n",
  84                                 value);
  85                 else
  86                         data->temp_input = value;
  87
  88                 for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) {
  89                         value = ad7414_read(client, AD7414_REG_LIMIT[i]);
  90                         if (value < 0)
  91                                 dev_dbg(&client->dev, "AD7414 reg %d err %d\n",
  92                                         AD7414_REG_LIMIT[i], value);
  93                         else
  94                                 data->temps[i] = value;
  95                 }
  96
  97                 data->next_update = jiffies + HZ + HZ / 2;
  98                 data->valid = 1;
  99         }
 100
 101         mutex_unlock(&data->lock);
 102
 103         return data;
 104 }
 105
 106 static ssize_t temp_input_show(struct device *dev,
 107                                struct device_attribute *attr, char *buf)
 108 {
 109         struct ad7414_data *data = ad7414_update_device(dev);
 110         return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input));
 111 }
 112 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_input, 0);
 113
 114 static ssize_t max_min_show(struct device *dev, struct device_attribute *attr,
 115                             char *buf)
 116 {
 117         int index = to_sensor_dev_attr(attr)->index;
 118         struct ad7414_data *data = ad7414_update_device(dev);
 119         return sprintf(buf, "%d\n", data->temps[index] * 1000);
 120 }
 121
 122 static ssize_t max_min_store(struct device *dev,
 123                              struct device_attribute *attr, const char *buf,
 124                              size_t count)
 125 {
 126         struct ad7414_data *data = dev_get_drvdata(dev);
 127         struct i2c_client *client = data->client;
 128         int index = to_sensor_dev_attr(attr)->index;
 129         u8 reg = AD7414_REG_LIMIT[index];
 130         long temp;
 131         int ret = kstrtol(buf, 10, &temp);
 132
 133         if (ret < 0)
 134                 return ret;
 135
 136         temp = clamp_val(temp, -40000, 85000);
 137         temp = (temp + (temp < 0 ? -500 : 500)) / 1000;
 138
 139         mutex_lock(&data->lock);
 140         data->temps[index] = temp;
 141         ad7414_write(client, reg, temp);
 142         mutex_unlock(&data->lock);
 143         return count;
 144 }
 145
 146 static SENSOR_DEVICE_ATTR_RW(temp1_max, max_min, 0);
 147 static SENSOR_DEVICE_ATTR_RW(temp1_min, max_min, 1);
 148
 149 static ssize_t alarm_show(struct device *dev, struct device_attribute *attr,
 150                           char *buf)
 151 {
 152         int bitnr = to_sensor_dev_attr(attr)->index;
 153         struct ad7414_data *data = ad7414_update_device(dev);
 154         int value = (data->temp_input >> bitnr) & 1;
 155         return sprintf(buf, "%d\n", value);
 156 }
 157
 158 static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 3);
 159 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 4);
 160
 161 static struct attribute *ad7414_attrs[] = {
 162         &sensor_dev_attr_temp1_input.dev_attr.attr,
 163         &sensor_dev_attr_temp1_max.dev_attr.attr,
 164         &sensor_dev_attr_temp1_min.dev_attr.attr,
 165         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 166         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 167         NULL
 168 };
 169
 170 ATTRIBUTE_GROUPS(ad7414);
 171
 172 static int ad7414_probe(struct i2c_client *client,
 173                         const struct i2c_device_id *dev_id)
 174 {
 175         struct device *dev = &client->dev;
 176         struct ad7414_data *data;
 177         struct device *hwmon_dev;
 178         int conf;
 179
 180         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 181                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 182                 return -EOPNOTSUPP;
 183
 184         data = devm_kzalloc(dev, sizeof(struct ad7414_data), GFP_KERNEL);
 185         if (!data)
 186                 return -ENOMEM;
 187
 188         data->client = client;
 189         mutex_init(&data->lock);
 190
 191         dev_info(&client->dev, "chip found\n");
 192
 193         /* Make sure the chip is powered up. */
 194         conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
 195         if (conf < 0)
 196                 dev_warn(dev, "ad7414_probe unable to read config register.\n");
 197         else {
 198                 conf &= ~(1 << 7);
 199                 i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
 200         }
 201
 202         hwmon_dev = devm_hwmon_device_register_with_groups(dev,
 203                                                            client->name,
 204                                                            data, ad7414_groups);
 205         return PTR_ERR_OR_ZERO(hwmon_dev);
 206 }
 207
 208 static const struct i2c_device_id ad7414_id[] = {
 209         { "ad7414", 0 },
 210         {}
 211 };
 212 MODULE_DEVICE_TABLE(i2c, ad7414_id);
 213
 214 static const struct of_device_id __maybe_unused ad7414_of_match[] = {
 215         { .compatible = "ad,ad7414" },
 216         { },
 217 };
 218 MODULE_DEVICE_TABLE(of, ad7414_of_match);
 219
 220 static struct i2c_driver ad7414_driver = {
 221         .driver = {
 222                 .name   = "ad7414",
 223                 .of_match_table = of_match_ptr(ad7414_of_match),
 224         },
 225         .probe  = ad7414_probe,
 226         .id_table = ad7414_id,
 227 };
 228
 229 module_i2c_driver(ad7414_driver);
 230
 231 MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
 232               "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
 233
 234 MODULE_DESCRIPTION("AD7414 driver");
 235 MODULE_LICENSE("GPL");