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 31 32 /* AD7414 registers */ 33 #define AD7414_REG_TEMP 0x00 34 #define AD7414_REG_CONF 0x01 35 #define AD7414_REG_T_HIGH 0x02 36 #define AD7414_REG_T_LOW 0x03 37 38 static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW }; 39 40 struct ad7414_data { 41 struct device *hwmon_dev; 42 struct mutex lock; /* atomic read data updates */ 43 char valid; /* !=0 if following fields are valid */ 44 unsigned long next_update; /* In jiffies */ 45 s16 temp_input; /* Register values */ 46 s8 temps[ARRAY_SIZE(AD7414_REG_LIMIT)]; 47 }; 48 49 /* REG: (0.25C/bit, two's complement) << 6 */ 50 static inline int ad7414_temp_from_reg(s16 reg) 51 { 52 /* use integer division instead of equivalent right shift to 53 * guarantee arithmetic shift and preserve the sign 54 */ 55 return ((int)reg / 64) * 250; 56 } 57 58 static inline int ad7414_read(struct i2c_client *client, u8 reg) 59 { 60 if (reg == AD7414_REG_TEMP) { 61 int value = i2c_smbus_read_word_data(client, reg); 62 return (value < 0) ? value : swab16(value); 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 = 0; 181 182 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA | 183 I2C_FUNC_SMBUS_READ_WORD_DATA)) 184 goto exit; 185 186 data = kzalloc(sizeof(struct ad7414_data), GFP_KERNEL); 187 if (!data) { 188 err = -ENOMEM; 189 goto exit; 190 } 191 192 i2c_set_clientdata(client, data); 193 mutex_init(&data->lock); 194 195 dev_info(&client->dev, "chip found\n"); 196 197 /* Make sure the chip is powered up. */ 198 conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF); 199 if (conf < 0) 200 dev_warn(&client->dev, 201 "ad7414_probe unable to read config register.\n"); 202 else { 203 conf &= ~(1 << 7); 204 i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf); 205 } 206 207 /* Register sysfs hooks */ 208 err = sysfs_create_group(&client->dev.kobj, &ad7414_group); 209 if (err) 210 goto exit_free; 211 212 data->hwmon_dev = hwmon_device_register(&client->dev); 213 if (IS_ERR(data->hwmon_dev)) { 214 err = PTR_ERR(data->hwmon_dev); 215 goto exit_remove; 216 } 217 218 return 0; 219 220 exit_remove: 221 sysfs_remove_group(&client->dev.kobj, &ad7414_group); 222 exit_free: 223 kfree(data); 224 exit: 225 return err; 226 } 227 228 static int __devexit ad7414_remove(struct i2c_client *client) 229 { 230 struct ad7414_data *data = i2c_get_clientdata(client); 231 232 hwmon_device_unregister(data->hwmon_dev); 233 sysfs_remove_group(&client->dev.kobj, &ad7414_group); 234 kfree(data); 235 return 0; 236 } 237 238 static const struct i2c_device_id ad7414_id[] = { 239 { "ad7414", 0 }, 240 {} 241 }; 242 243 static struct i2c_driver ad7414_driver = { 244 .driver = { 245 .name = "ad7414", 246 }, 247 .probe = ad7414_probe, 248 .remove = __devexit_p(ad7414_remove), 249 .id_table = ad7414_id, 250 }; 251 252 static int __init ad7414_init(void) 253 { 254 return i2c_add_driver(&ad7414_driver); 255 } 256 module_init(ad7414_init); 257 258 static void __exit ad7414_exit(void) 259 { 260 i2c_del_driver(&ad7414_driver); 261 } 262 module_exit(ad7414_exit); 263 264 MODULE_AUTHOR("Stefan Roese <sr at denx.de>, " 265 "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>"); 266 267 MODULE_DESCRIPTION("AD7414 driver"); 268 MODULE_LICENSE("GPL"); 269