1 /* 2 * An hwmon driver for the Analog Devices AD7414 3 * 4 * Copyright 2006 Stefan Roese <sr at denx.de>, DENX Software Engineering 5 * 6 * Copyright (c) 2008 PIKA Technologies 7 * Sean MacLennan <smaclennan@pikatech.com> 8 * 9 * Copyright (c) 2008 Spansion Inc. 10 * Frank Edelhaeuser <frank.edelhaeuser at spansion.com> 11 * (converted to "new style" I2C driver model, removed checkpatch.pl warnings) 12 * 13 * Based on ad7418.c 14 * Copyright 2006 Tower Technologies, Alessandro Zummo <a.zummo at towertech.it> 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License as published by 18 * the Free Software Foundation; either version 2 of the License, or 19 * (at your option) any later version. 20 */ 21 22 #include <linux/module.h> 23 #include <linux/jiffies.h> 24 #include <linux/i2c.h> 25 #include <linux/hwmon.h> 26 #include <linux/hwmon-sysfs.h> 27 #include <linux/err.h> 28 #include <linux/mutex.h> 29 #include <linux/sysfs.h> 30 #include <linux/slab.h> 31 32 33 /* AD7414 registers */ 34 #define AD7414_REG_TEMP 0x00 35 #define AD7414_REG_CONF 0x01 36 #define AD7414_REG_T_HIGH 0x02 37 #define AD7414_REG_T_LOW 0x03 38 39 static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW }; 40 41 struct ad7414_data { 42 struct device *hwmon_dev; 43 struct mutex lock; /* atomic read data updates */ 44 char valid; /* !=0 if following fields are valid */ 45 unsigned long next_update; /* In jiffies */ 46 s16 temp_input; /* Register values */ 47 s8 temps[ARRAY_SIZE(AD7414_REG_LIMIT)]; 48 }; 49 50 /* REG: (0.25C/bit, two's complement) << 6 */ 51 static inline int ad7414_temp_from_reg(s16 reg) 52 { 53 /* use integer division instead of equivalent right shift to 54 * guarantee arithmetic shift and preserve the sign 55 */ 56 return ((int)reg / 64) * 250; 57 } 58 59 static inline int ad7414_read(struct i2c_client *client, u8 reg) 60 { 61 if (reg == AD7414_REG_TEMP) 62 return i2c_smbus_read_word_swapped(client, reg); 63 else 64 return i2c_smbus_read_byte_data(client, reg); 65 } 66 67 static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value) 68 { 69 return i2c_smbus_write_byte_data(client, reg, value); 70 } 71 72 static struct ad7414_data *ad7414_update_device(struct device *dev) 73 { 74 struct i2c_client *client = to_i2c_client(dev); 75 struct ad7414_data *data = i2c_get_clientdata(client); 76 77 mutex_lock(&data->lock); 78 79 if (time_after(jiffies, data->next_update) || !data->valid) { 80 int value, i; 81 82 dev_dbg(&client->dev, "starting ad7414 update\n"); 83 84 value = ad7414_read(client, AD7414_REG_TEMP); 85 if (value < 0) 86 dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n", 87 value); 88 else 89 data->temp_input = value; 90 91 for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) { 92 value = ad7414_read(client, AD7414_REG_LIMIT[i]); 93 if (value < 0) 94 dev_dbg(&client->dev, "AD7414 reg %d err %d\n", 95 AD7414_REG_LIMIT[i], value); 96 else 97 data->temps[i] = value; 98 } 99 100 data->next_update = jiffies + HZ + HZ / 2; 101 data->valid = 1; 102 } 103 104 mutex_unlock(&data->lock); 105 106 return data; 107 } 108 109 static ssize_t show_temp_input(struct device *dev, 110 struct device_attribute *attr, char *buf) 111 { 112 struct ad7414_data *data = ad7414_update_device(dev); 113 return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input)); 114 } 115 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0); 116 117 static ssize_t show_max_min(struct device *dev, struct device_attribute *attr, 118 char *buf) 119 { 120 int index = to_sensor_dev_attr(attr)->index; 121 struct ad7414_data *data = ad7414_update_device(dev); 122 return sprintf(buf, "%d\n", data->temps[index] * 1000); 123 } 124 125 static ssize_t set_max_min(struct device *dev, 126 struct device_attribute *attr, 127 const char *buf, size_t count) 128 { 129 struct i2c_client *client = to_i2c_client(dev); 130 struct ad7414_data *data = i2c_get_clientdata(client); 131 int index = to_sensor_dev_attr(attr)->index; 132 u8 reg = AD7414_REG_LIMIT[index]; 133 long temp = simple_strtol(buf, NULL, 10); 134 135 temp = SENSORS_LIMIT(temp, -40000, 85000); 136 temp = (temp + (temp < 0 ? -500 : 500)) / 1000; 137 138 mutex_lock(&data->lock); 139 data->temps[index] = temp; 140 ad7414_write(client, reg, temp); 141 mutex_unlock(&data->lock); 142 return count; 143 } 144 145 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 146 show_max_min, set_max_min, 0); 147 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, 148 show_max_min, set_max_min, 1); 149 150 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 151 char *buf) 152 { 153 int bitnr = to_sensor_dev_attr(attr)->index; 154 struct ad7414_data *data = ad7414_update_device(dev); 155 int value = (data->temp_input >> bitnr) & 1; 156 return sprintf(buf, "%d\n", value); 157 } 158 159 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3); 160 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4); 161 162 static struct attribute *ad7414_attributes[] = { 163 &sensor_dev_attr_temp1_input.dev_attr.attr, 164 &sensor_dev_attr_temp1_max.dev_attr.attr, 165 &sensor_dev_attr_temp1_min.dev_attr.attr, 166 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 167 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 168 NULL 169 }; 170 171 static const struct attribute_group ad7414_group = { 172 .attrs = ad7414_attributes, 173 }; 174 175 static int ad7414_probe(struct i2c_client *client, 176 const struct i2c_device_id *dev_id) 177 { 178 struct ad7414_data *data; 179 int conf; 180 int err; 181 182 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA | 183 I2C_FUNC_SMBUS_READ_WORD_DATA)) { 184 err = -EOPNOTSUPP; 185 goto exit; 186 } 187 188 data = kzalloc(sizeof(struct ad7414_data), GFP_KERNEL); 189 if (!data) { 190 err = -ENOMEM; 191 goto exit; 192 } 193 194 i2c_set_clientdata(client, data); 195 mutex_init(&data->lock); 196 197 dev_info(&client->dev, "chip found\n"); 198 199 /* Make sure the chip is powered up. */ 200 conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF); 201 if (conf < 0) 202 dev_warn(&client->dev, 203 "ad7414_probe unable to read config register.\n"); 204 else { 205 conf &= ~(1 << 7); 206 i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf); 207 } 208 209 /* Register sysfs hooks */ 210 err = sysfs_create_group(&client->dev.kobj, &ad7414_group); 211 if (err) 212 goto exit_free; 213 214 data->hwmon_dev = hwmon_device_register(&client->dev); 215 if (IS_ERR(data->hwmon_dev)) { 216 err = PTR_ERR(data->hwmon_dev); 217 goto exit_remove; 218 } 219 220 return 0; 221 222 exit_remove: 223 sysfs_remove_group(&client->dev.kobj, &ad7414_group); 224 exit_free: 225 kfree(data); 226 exit: 227 return err; 228 } 229 230 static int __devexit ad7414_remove(struct i2c_client *client) 231 { 232 struct ad7414_data *data = i2c_get_clientdata(client); 233 234 hwmon_device_unregister(data->hwmon_dev); 235 sysfs_remove_group(&client->dev.kobj, &ad7414_group); 236 kfree(data); 237 return 0; 238 } 239 240 static const struct i2c_device_id ad7414_id[] = { 241 { "ad7414", 0 }, 242 {} 243 }; 244 MODULE_DEVICE_TABLE(i2c, ad7414_id); 245 246 static struct i2c_driver ad7414_driver = { 247 .driver = { 248 .name = "ad7414", 249 }, 250 .probe = ad7414_probe, 251 .remove = __devexit_p(ad7414_remove), 252 .id_table = ad7414_id, 253 }; 254 255 static int __init ad7414_init(void) 256 { 257 return i2c_add_driver(&ad7414_driver); 258 } 259 module_init(ad7414_init); 260 261 static void __exit ad7414_exit(void) 262 { 263 i2c_del_driver(&ad7414_driver); 264 } 265 module_exit(ad7414_exit); 266 267 MODULE_AUTHOR("Stefan Roese <sr at denx.de>, " 268 "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>"); 269 270 MODULE_DESCRIPTION("AD7414 driver"); 271 MODULE_LICENSE("GPL"); 272