drivers/hwmon/pcf8591.c

   1 /*
   2     Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
   3     Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
   4     the help of Jean Delvare <khali@linux-fr.org>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/slab.h>
  24 #include <linux/i2c.h>
  25 #include <linux/mutex.h>
  26 #include <linux/err.h>
  27 #include <linux/hwmon.h>
  28
  29 /* Insmod parameters */
  30
  31 static int input_mode;
  32 module_param(input_mode, int, 0);
  33 MODULE_PARM_DESC(input_mode,
  34         "Analog input mode:\n"
  35         " 0 = four single ended inputs\n"
  36         " 1 = three differential inputs\n"
  37         " 2 = single ended and differential mixed\n"
  38         " 3 = two differential inputs\n");
  39
  40 /* The PCF8591 control byte
  41       7    6    5    4    3    2    1    0
  42    |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */
  43
  44 /* Analog Output Enable Flag (analog output active if 1) */
  45 #define PCF8591_CONTROL_AOEF            0x40
  46
  47 /* Analog Input Programming
  48    0x00 = four single ended inputs
  49    0x10 = three differential inputs
  50    0x20 = single ended and differential mixed
  51    0x30 = two differential inputs */
  52 #define PCF8591_CONTROL_AIP_MASK        0x30
  53
  54 /* Autoincrement Flag (switch on if 1) */
  55 #define PCF8591_CONTROL_AINC            0x04
  56
  57 /* Channel selection
  58    0x00 = channel 0
  59    0x01 = channel 1
  60    0x02 = channel 2
  61    0x03 = channel 3 */
  62 #define PCF8591_CONTROL_AICH_MASK       0x03
  63
  64 /* Initial values */
  65 #define PCF8591_INIT_CONTROL    ((input_mode << 4) | PCF8591_CONTROL_AOEF)
  66 #define PCF8591_INIT_AOUT       0       /* DAC out = 0 */
  67
  68 /* Conversions */
  69 #define REG_TO_SIGNED(reg)      (((reg) & 0x80)?((reg) - 256):(reg))
  70
  71 struct pcf8591_data {
  72         struct device *hwmon_dev;
  73         struct mutex update_lock;
  74
  75         u8 control;
  76         u8 aout;
  77 };
  78
  79 static void pcf8591_init_client(struct i2c_client *client);
  80 static int pcf8591_read_channel(struct device *dev, int channel);
  81
  82 /* following are the sysfs callback functions */
  83 #define show_in_channel(channel)                                        \
  84 static ssize_t show_in##channel##_input(struct device *dev, struct device_attribute *attr, char *buf)   \
  85 {                                                                       \
  86         return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
  87 }                                                                       \
  88 static DEVICE_ATTR(in##channel##_input, S_IRUGO,                        \
  89                    show_in##channel##_input, NULL);
  90
  91 show_in_channel(0);
  92 show_in_channel(1);
  93 show_in_channel(2);
  94 show_in_channel(3);
  95
  96 static ssize_t show_out0_ouput(struct device *dev, struct device_attribute *attr, char *buf)
  97 {
  98         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
  99         return sprintf(buf, "%d\n", data->aout * 10);
 100 }
 101
 102 static ssize_t set_out0_output(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 103 {
 104         unsigned int value;
 105         struct i2c_client *client = to_i2c_client(dev);
 106         struct pcf8591_data *data = i2c_get_clientdata(client);
 107         if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
 108                 data->aout = value;
 109                 i2c_smbus_write_byte_data(client, data->control, data->aout);
 110                 return count;
 111         }
 112         return -EINVAL;
 113 }
 114
 115 static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
 116                    show_out0_ouput, set_out0_output);
 117
 118 static ssize_t show_out0_enable(struct device *dev, struct device_attribute *attr, char *buf)
 119 {
 120         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 121         return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
 122 }
 123
 124 static ssize_t set_out0_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 125 {
 126         struct i2c_client *client = to_i2c_client(dev);
 127         struct pcf8591_data *data = i2c_get_clientdata(client);
 128         unsigned long val = simple_strtoul(buf, NULL, 10);
 129
 130         mutex_lock(&data->update_lock);
 131         if (val)
 132                 data->control |= PCF8591_CONTROL_AOEF;
 133         else
 134                 data->control &= ~PCF8591_CONTROL_AOEF;
 135         i2c_smbus_write_byte(client, data->control);
 136         mutex_unlock(&data->update_lock);
 137         return count;
 138 }
 139
 140 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
 141                    show_out0_enable, set_out0_enable);
 142
 143 static struct attribute *pcf8591_attributes[] = {
 144         &dev_attr_out0_enable.attr,
 145         &dev_attr_out0_output.attr,
 146         &dev_attr_in0_input.attr,
 147         &dev_attr_in1_input.attr,
 148         NULL
 149 };
 150
 151 static const struct attribute_group pcf8591_attr_group = {
 152         .attrs = pcf8591_attributes,
 153 };
 154
 155 static struct attribute *pcf8591_attributes_opt[] = {
 156         &dev_attr_in2_input.attr,
 157         &dev_attr_in3_input.attr,
 158         NULL
 159 };
 160
 161 static const struct attribute_group pcf8591_attr_group_opt = {
 162         .attrs = pcf8591_attributes_opt,
 163 };
 164
 165 /*
 166  * Real code
 167  */
 168
 169 static int pcf8591_probe(struct i2c_client *client,
 170                          const struct i2c_device_id *id)
 171 {
 172         struct pcf8591_data *data;
 173         int err;
 174
 175         if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
 176                 err = -ENOMEM;
 177                 goto exit;
 178         }
 179
 180         i2c_set_clientdata(client, data);
 181         mutex_init(&data->update_lock);
 182
 183         /* Initialize the PCF8591 chip */
 184         pcf8591_init_client(client);
 185
 186         /* Register sysfs hooks */
 187         err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
 188         if (err)
 189                 goto exit_kfree;
 190
 191         /* Register input2 if not in "two differential inputs" mode */
 192         if (input_mode != 3) {
 193                 if ((err = device_create_file(&client->dev,
 194                                               &dev_attr_in2_input)))
 195                         goto exit_sysfs_remove;
 196         }
 197
 198         /* Register input3 only in "four single ended inputs" mode */
 199         if (input_mode == 0) {
 200                 if ((err = device_create_file(&client->dev,
 201                                               &dev_attr_in3_input)))
 202                         goto exit_sysfs_remove;
 203         }
 204
 205         data->hwmon_dev = hwmon_device_register(&client->dev);
 206         if (IS_ERR(data->hwmon_dev)) {
 207                 err = PTR_ERR(data->hwmon_dev);
 208                 goto exit_sysfs_remove;
 209         }
 210
 211         return 0;
 212
 213 exit_sysfs_remove:
 214         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
 215         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 216 exit_kfree:
 217         kfree(data);
 218 exit:
 219         return err;
 220 }
 221
 222 static int pcf8591_remove(struct i2c_client *client)
 223 {
 224         struct pcf8591_data *data = i2c_get_clientdata(client);
 225
 226         hwmon_device_unregister(data->hwmon_dev);
 227         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
 228         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 229         kfree(i2c_get_clientdata(client));
 230         return 0;
 231 }
 232
 233 /* Called when we have found a new PCF8591. */
 234 static void pcf8591_init_client(struct i2c_client *client)
 235 {
 236         struct pcf8591_data *data = i2c_get_clientdata(client);
 237         data->control = PCF8591_INIT_CONTROL;
 238         data->aout = PCF8591_INIT_AOUT;
 239
 240         i2c_smbus_write_byte_data(client, data->control, data->aout);
 241
 242         /* The first byte transmitted contains the conversion code of the
 243            previous read cycle. FLUSH IT! */
 244         i2c_smbus_read_byte(client);
 245 }
 246
 247 static int pcf8591_read_channel(struct device *dev, int channel)
 248 {
 249         u8 value;
 250         struct i2c_client *client = to_i2c_client(dev);
 251         struct pcf8591_data *data = i2c_get_clientdata(client);
 252
 253         mutex_lock(&data->update_lock);
 254
 255         if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
 256                 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
 257                               | channel;
 258                 i2c_smbus_write_byte(client, data->control);
 259
 260                 /* The first byte transmitted contains the conversion code of
 261                    the previous read cycle. FLUSH IT! */
 262                 i2c_smbus_read_byte(client);
 263         }
 264         value = i2c_smbus_read_byte(client);
 265
 266         mutex_unlock(&data->update_lock);
 267
 268         if ((channel == 2 && input_mode == 2) ||
 269             (channel != 3 && (input_mode == 1 || input_mode == 3)))
 270                 return (10 * REG_TO_SIGNED(value));
 271         else
 272                 return (10 * value);
 273 }
 274
 275 static const struct i2c_device_id pcf8591_id[] = {
 276         { "pcf8591", 0 },
 277         { }
 278 };
 279 MODULE_DEVICE_TABLE(i2c, pcf8591_id);
 280
 281 static struct i2c_driver pcf8591_driver = {
 282         .driver = {
 283                 .name   = "pcf8591",
 284         },
 285         .probe          = pcf8591_probe,
 286         .remove         = pcf8591_remove,
 287         .id_table       = pcf8591_id,
 288 };
 289
 290 static int __init pcf8591_init(void)
 291 {
 292         if (input_mode < 0 || input_mode > 3) {
 293                 printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
 294                        input_mode);
 295                 input_mode = 0;
 296         }
 297         return i2c_add_driver(&pcf8591_driver);
 298 }
 299
 300 static void __exit pcf8591_exit(void)
 301 {
 302         i2c_del_driver(&pcf8591_driver);
 303 }
 304
 305 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
 306 MODULE_DESCRIPTION("PCF8591 driver");
 307 MODULE_LICENSE("GPL");
 308
 309 module_init(pcf8591_init);
 310 module_exit(pcf8591_exit);