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 /* 54 * use integer division instead of equivalent right shift to 55 * guarantee arithmetic shift and preserve the sign 56 */ 57 return ((int)reg / 64) * 250; 58 } 59 60 static inline int ad7414_read(struct i2c_client *client, u8 reg) 61 { 62 if (reg == AD7414_REG_TEMP) 63 return i2c_smbus_read_word_swapped(client, reg); 64 else 65 return i2c_smbus_read_byte_data(client, reg); 66 } 67 68 static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value) 69 { 70 return i2c_smbus_write_byte_data(client, reg, value); 71 } 72 73 static struct ad7414_data *ad7414_update_device(struct device *dev) 74 { 75 struct i2c_client *client = to_i2c_client(dev); 76 struct ad7414_data *data = i2c_get_clientdata(client); 77 78 mutex_lock(&data->lock); 79 80 if (time_after(jiffies, data->next_update) || !data->valid) { 81 int value, i; 82 83 dev_dbg(&client->dev, "starting ad7414 update\n"); 84 85 value = ad7414_read(client, AD7414_REG_TEMP); 86 if (value < 0) 87 dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n", 88 value); 89 else 90 data->temp_input = value; 91 92 for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) { 93 value = ad7414_read(client, AD7414_REG_LIMIT[i]); 94 if (value < 0) 95 dev_dbg(&client->dev, "AD7414 reg %d err %d\n", 96 AD7414_REG_LIMIT[i], value); 97 else 98 data->temps[i] = value; 99 } 100 101 data->next_update = jiffies + HZ + HZ / 2; 102 data->valid = 1; 103 } 104 105 mutex_unlock(&data->lock); 106 107 return data; 108 } 109 110 static ssize_t show_temp_input(struct device *dev, 111 struct device_attribute *attr, char *buf) 112 { 113 struct ad7414_data *data = ad7414_update_device(dev); 114 return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input)); 115 } 116 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0); 117 118 static ssize_t show_max_min(struct device *dev, struct device_attribute *attr, 119 char *buf) 120 { 121 int index = to_sensor_dev_attr(attr)->index; 122 struct ad7414_data *data = ad7414_update_device(dev); 123 return sprintf(buf, "%d\n", data->temps[index] * 1000); 124 } 125 126 static ssize_t set_max_min(struct device *dev, 127 struct device_attribute *attr, 128 const char *buf, size_t count) 129 { 130 struct i2c_client *client = to_i2c_client(dev); 131 struct ad7414_data *data = i2c_get_clientdata(client); 132 int index = to_sensor_dev_attr(attr)->index; 133 u8 reg = AD7414_REG_LIMIT[index]; 134 long temp; 135 int ret = kstrtol(buf, 10, &temp); 136 137 if (ret < 0) 138 return ret; 139 140 temp = clamp_val(temp, -40000, 85000); 141 temp = (temp + (temp < 0 ? -500 : 500)) / 1000; 142 143 mutex_lock(&data->lock); 144 data->temps[index] = temp; 145 ad7414_write(client, reg, temp); 146 mutex_unlock(&data->lock); 147 return count; 148 } 149 150 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 151 show_max_min, set_max_min, 0); 152 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, 153 show_max_min, set_max_min, 1); 154 155 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 156 char *buf) 157 { 158 int bitnr = to_sensor_dev_attr(attr)->index; 159 struct ad7414_data *data = ad7414_update_device(dev); 160 int value = (data->temp_input >> bitnr) & 1; 161 return sprintf(buf, "%d\n", value); 162 } 163 164 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3); 165 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4); 166 167 static struct attribute *ad7414_attributes[] = { 168 &sensor_dev_attr_temp1_input.dev_attr.attr, 169 &sensor_dev_attr_temp1_max.dev_attr.attr, 170 &sensor_dev_attr_temp1_min.dev_attr.attr, 171 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 172 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 173 NULL 174 }; 175 176 static const struct attribute_group ad7414_group = { 177 .attrs = ad7414_attributes, 178 }; 179 180 static int ad7414_probe(struct i2c_client *client, 181 const struct i2c_device_id *dev_id) 182 { 183 struct ad7414_data *data; 184 int conf; 185 int err; 186 187 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA | 188 I2C_FUNC_SMBUS_READ_WORD_DATA)) 189 return -EOPNOTSUPP; 190 191 data = devm_kzalloc(&client->dev, sizeof(struct ad7414_data), 192 GFP_KERNEL); 193 if (!data) 194 return -ENOMEM; 195 196 i2c_set_clientdata(client, data); 197 mutex_init(&data->lock); 198 199 dev_info(&client->dev, "chip found\n"); 200 201 /* Make sure the chip is powered up. */ 202 conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF); 203 if (conf < 0) 204 dev_warn(&client->dev, 205 "ad7414_probe unable to read config register.\n"); 206 else { 207 conf &= ~(1 << 7); 208 i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf); 209 } 210 211 /* Register sysfs hooks */ 212 err = sysfs_create_group(&client->dev.kobj, &ad7414_group); 213 if (err) 214 return err; 215 216 data->hwmon_dev = hwmon_device_register(&client->dev); 217 if (IS_ERR(data->hwmon_dev)) { 218 err = PTR_ERR(data->hwmon_dev); 219 goto exit_remove; 220 } 221 222 return 0; 223 224 exit_remove: 225 sysfs_remove_group(&client->dev.kobj, &ad7414_group); 226 return err; 227 } 228 229 static int ad7414_remove(struct i2c_client *client) 230 { 231 struct ad7414_data *data = i2c_get_clientdata(client); 232 233 hwmon_device_unregister(data->hwmon_dev); 234 sysfs_remove_group(&client->dev.kobj, &ad7414_group); 235 return 0; 236 } 237 238 static const struct i2c_device_id ad7414_id[] = { 239 { "ad7414", 0 }, 240 {} 241 }; 242 MODULE_DEVICE_TABLE(i2c, ad7414_id); 243 244 static struct i2c_driver ad7414_driver = { 245 .driver = { 246 .name = "ad7414", 247 }, 248 .probe = ad7414_probe, 249 .remove = ad7414_remove, 250 .id_table = ad7414_id, 251 }; 252 253 module_i2c_driver(ad7414_driver); 254 255 MODULE_AUTHOR("Stefan Roese <sr at denx.de>, " 256 "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>"); 257 258 MODULE_DESCRIPTION("AD7414 driver"); 259 MODULE_LICENSE("GPL"); 260