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
  27 /* Addresses to scan */
  28 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  29                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  30
  31 /* Insmod parameters */
  32 I2C_CLIENT_INSMOD_1(pcf8591);
  33
  34 static int input_mode;
  35 module_param(input_mode, int, 0);
  36 MODULE_PARM_DESC(input_mode,
  37         "Analog input mode:\n"
  38         " 0 = four single ended inputs\n"
  39         " 1 = three differential inputs\n"
  40         " 2 = single ended and differential mixed\n"
  41         " 3 = two differential inputs\n");
  42
  43 /* The PCF8591 control byte
  44       7    6    5    4    3    2    1    0
  45    |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */
  46
  47 /* Analog Output Enable Flag (analog output active if 1) */
  48 #define PCF8591_CONTROL_AOEF            0x40
  49
  50 /* Analog Input Programming
  51    0x00 = four single ended inputs
  52    0x10 = three differential inputs
  53    0x20 = single ended and differential mixed
  54    0x30 = two differential inputs */
  55 #define PCF8591_CONTROL_AIP_MASK        0x30
  56
  57 /* Autoincrement Flag (switch on if 1) */
  58 #define PCF8591_CONTROL_AINC            0x04
  59
  60 /* Channel selection
  61    0x00 = channel 0
  62    0x01 = channel 1
  63    0x02 = channel 2
  64    0x03 = channel 3 */
  65 #define PCF8591_CONTROL_AICH_MASK       0x03
  66
  67 /* Initial values */
  68 #define PCF8591_INIT_CONTROL    ((input_mode << 4) | PCF8591_CONTROL_AOEF)
  69 #define PCF8591_INIT_AOUT       0       /* DAC out = 0 */
  70
  71 /* Conversions */
  72 #define REG_TO_SIGNED(reg)      (((reg) & 0x80)?((reg) - 256):(reg))
  73
  74 struct pcf8591_data {
  75         struct mutex update_lock;
  76
  77         u8 control;
  78         u8 aout;
  79 };
  80
  81 static void pcf8591_init_client(struct i2c_client *client);
  82 static int pcf8591_read_channel(struct device *dev, int channel);
  83
  84 /* following are the sysfs callback functions */
  85 #define show_in_channel(channel)                                        \
  86 static ssize_t show_in##channel##_input(struct device *dev, struct device_attribute *attr, char *buf)   \
  87 {                                                                       \
  88         return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
  89 }                                                                       \
  90 static DEVICE_ATTR(in##channel##_input, S_IRUGO,                        \
  91                    show_in##channel##_input, NULL);
  92
  93 show_in_channel(0);
  94 show_in_channel(1);
  95 show_in_channel(2);
  96 show_in_channel(3);
  97
  98 static ssize_t show_out0_ouput(struct device *dev, struct device_attribute *attr, char *buf)
  99 {
 100         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 101         return sprintf(buf, "%d\n", data->aout * 10);
 102 }
 103
 104 static ssize_t set_out0_output(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 105 {
 106         unsigned int value;
 107         struct i2c_client *client = to_i2c_client(dev);
 108         struct pcf8591_data *data = i2c_get_clientdata(client);
 109         if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
 110                 data->aout = value;
 111                 i2c_smbus_write_byte_data(client, data->control, data->aout);
 112                 return count;
 113         }
 114         return -EINVAL;
 115 }
 116
 117 static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
 118                    show_out0_ouput, set_out0_output);
 119
 120 static ssize_t show_out0_enable(struct device *dev, struct device_attribute *attr, char *buf)
 121 {
 122         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 123         return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
 124 }
 125
 126 static ssize_t set_out0_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 127 {
 128         struct i2c_client *client = to_i2c_client(dev);
 129         struct pcf8591_data *data = i2c_get_clientdata(client);
 130         unsigned long val = simple_strtoul(buf, NULL, 10);
 131
 132         mutex_lock(&data->update_lock);
 133         if (val)
 134                 data->control |= PCF8591_CONTROL_AOEF;
 135         else
 136                 data->control &= ~PCF8591_CONTROL_AOEF;
 137         i2c_smbus_write_byte(client, data->control);
 138         mutex_unlock(&data->update_lock);
 139         return count;
 140 }
 141
 142 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
 143                    show_out0_enable, set_out0_enable);
 144
 145 static struct attribute *pcf8591_attributes[] = {
 146         &dev_attr_out0_enable.attr,
 147         &dev_attr_out0_output.attr,
 148         &dev_attr_in0_input.attr,
 149         &dev_attr_in1_input.attr,
 150         NULL
 151 };
 152
 153 static const struct attribute_group pcf8591_attr_group = {
 154         .attrs = pcf8591_attributes,
 155 };
 156
 157 static struct attribute *pcf8591_attributes_opt[] = {
 158         &dev_attr_in2_input.attr,
 159         &dev_attr_in3_input.attr,
 160         NULL
 161 };
 162
 163 static const struct attribute_group pcf8591_attr_group_opt = {
 164         .attrs = pcf8591_attributes_opt,
 165 };
 166
 167 /*
 168  * Real code
 169  */
 170
 171 /* Return 0 if detection is successful, -ENODEV otherwise */
 172 static int pcf8591_detect(struct i2c_client *client, int kind,
 173                           struct i2c_board_info *info)
 174 {
 175         struct i2c_adapter *adapter = client->adapter;
 176
 177         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
 178                                      | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 179                 return -ENODEV;
 180
 181         /* Now, we would do the remaining detection. But the PCF8591 is plainly
 182            impossible to detect! Stupid chip. */
 183
 184         strlcpy(info->type, "pcf8591", I2C_NAME_SIZE);
 185
 186         return 0;
 187 }
 188
 189 static int pcf8591_probe(struct i2c_client *client,
 190                          const struct i2c_device_id *id)
 191 {
 192         struct pcf8591_data *data;
 193         int err;
 194
 195         if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
 196                 err = -ENOMEM;
 197                 goto exit;
 198         }
 199
 200         i2c_set_clientdata(client, data);
 201         mutex_init(&data->update_lock);
 202
 203         /* Initialize the PCF8591 chip */
 204         pcf8591_init_client(client);
 205
 206         /* Register sysfs hooks */
 207         err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
 208         if (err)
 209                 goto exit_kfree;
 210
 211         /* Register input2 if not in "two differential inputs" mode */
 212         if (input_mode != 3) {
 213                 if ((err = device_create_file(&client->dev,
 214                                               &dev_attr_in2_input)))
 215                         goto exit_sysfs_remove;
 216         }
 217
 218         /* Register input3 only in "four single ended inputs" mode */
 219         if (input_mode == 0) {
 220                 if ((err = device_create_file(&client->dev,
 221                                               &dev_attr_in3_input)))
 222                         goto exit_sysfs_remove;
 223         }
 224
 225         return 0;
 226
 227 exit_sysfs_remove:
 228         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
 229         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 230 exit_kfree:
 231         kfree(data);
 232 exit:
 233         return err;
 234 }
 235
 236 static int pcf8591_remove(struct i2c_client *client)
 237 {
 238         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
 239         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 240         kfree(i2c_get_clientdata(client));
 241         return 0;
 242 }
 243
 244 /* Called when we have found a new PCF8591. */
 245 static void pcf8591_init_client(struct i2c_client *client)
 246 {
 247         struct pcf8591_data *data = i2c_get_clientdata(client);
 248         data->control = PCF8591_INIT_CONTROL;
 249         data->aout = PCF8591_INIT_AOUT;
 250
 251         i2c_smbus_write_byte_data(client, data->control, data->aout);
 252
 253         /* The first byte transmitted contains the conversion code of the
 254            previous read cycle. FLUSH IT! */
 255         i2c_smbus_read_byte(client);
 256 }
 257
 258 static int pcf8591_read_channel(struct device *dev, int channel)
 259 {
 260         u8 value;
 261         struct i2c_client *client = to_i2c_client(dev);
 262         struct pcf8591_data *data = i2c_get_clientdata(client);
 263
 264         mutex_lock(&data->update_lock);
 265
 266         if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
 267                 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
 268                               | channel;
 269                 i2c_smbus_write_byte(client, data->control);
 270
 271                 /* The first byte transmitted contains the conversion code of
 272                    the previous read cycle. FLUSH IT! */
 273                 i2c_smbus_read_byte(client);
 274         }
 275         value = i2c_smbus_read_byte(client);
 276
 277         mutex_unlock(&data->update_lock);
 278
 279         if ((channel == 2 && input_mode == 2) ||
 280             (channel != 3 && (input_mode == 1 || input_mode == 3)))
 281                 return (10 * REG_TO_SIGNED(value));
 282         else
 283                 return (10 * value);
 284 }
 285
 286 static const struct i2c_device_id pcf8591_id[] = {
 287         { "pcf8591", 0 },
 288         { }
 289 };
 290 MODULE_DEVICE_TABLE(i2c, pcf8591_id);
 291
 292 static struct i2c_driver pcf8591_driver = {
 293         .driver = {
 294                 .name   = "pcf8591",
 295         },
 296         .probe          = pcf8591_probe,
 297         .remove         = pcf8591_remove,
 298         .id_table       = pcf8591_id,
 299
 300         .class          = I2C_CLASS_HWMON,      /* Nearest choice */
 301         .detect         = pcf8591_detect,
 302         .address_data   = &addr_data,
 303 };
 304
 305 static int __init pcf8591_init(void)
 306 {
 307         if (input_mode < 0 || input_mode > 3) {
 308                 printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
 309                        input_mode);
 310                 input_mode = 0;
 311         }
 312         return i2c_add_driver(&pcf8591_driver);
 313 }
 314
 315 static void __exit pcf8591_exit(void)
 316 {
 317         i2c_del_driver(&pcf8591_driver);
 318 }
 319
 320 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
 321 MODULE_DESCRIPTION("PCF8591 driver");
 322 MODULE_LICENSE("GPL");
 323
 324 module_init(pcf8591_init);
 325 module_exit(pcf8591_exit);