drivers/i2c/chips/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 i2c_client client;
  76         struct mutex update_lock;
  77
  78         u8 control;
  79         u8 aout;
  80 };
  81
  82 static int pcf8591_attach_adapter(struct i2c_adapter *adapter);
  83 static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind);
  84 static int pcf8591_detach_client(struct i2c_client *client);
  85 static void pcf8591_init_client(struct i2c_client *client);
  86 static int pcf8591_read_channel(struct device *dev, int channel);
  87
  88 /* This is the driver that will be inserted */
  89 static struct i2c_driver pcf8591_driver = {
  90         .driver = {
  91                 .name   = "pcf8591",
  92         },
  93         .attach_adapter = pcf8591_attach_adapter,
  94         .detach_client  = pcf8591_detach_client,
  95 };
  96
  97 /* following are the sysfs callback functions */
  98 #define show_in_channel(channel)                                        \
  99 static ssize_t show_in##channel##_input(struct device *dev, struct device_attribute *attr, char *buf)   \
 100 {                                                                       \
 101         return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
 102 }                                                                       \
 103 static DEVICE_ATTR(in##channel##_input, S_IRUGO,                        \
 104                    show_in##channel##_input, NULL);
 105
 106 show_in_channel(0);
 107 show_in_channel(1);
 108 show_in_channel(2);
 109 show_in_channel(3);
 110
 111 static ssize_t show_out0_ouput(struct device *dev, struct device_attribute *attr, char *buf)
 112 {
 113         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 114         return sprintf(buf, "%d\n", data->aout * 10);
 115 }
 116
 117 static ssize_t set_out0_output(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 118 {
 119         unsigned int value;
 120         struct i2c_client *client = to_i2c_client(dev);
 121         struct pcf8591_data *data = i2c_get_clientdata(client);
 122         if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
 123                 data->aout = value;
 124                 i2c_smbus_write_byte_data(client, data->control, data->aout);
 125                 return count;
 126         }
 127         return -EINVAL;
 128 }
 129
 130 static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
 131                    show_out0_ouput, set_out0_output);
 132
 133 static ssize_t show_out0_enable(struct device *dev, struct device_attribute *attr, char *buf)
 134 {
 135         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 136         return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
 137 }
 138
 139 static ssize_t set_out0_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 140 {
 141         struct i2c_client *client = to_i2c_client(dev);
 142         struct pcf8591_data *data = i2c_get_clientdata(client);
 143         unsigned long val = simple_strtoul(buf, NULL, 10);
 144
 145         mutex_lock(&data->update_lock);
 146         if (val)
 147                 data->control |= PCF8591_CONTROL_AOEF;
 148         else
 149                 data->control &= ~PCF8591_CONTROL_AOEF;
 150         i2c_smbus_write_byte(client, data->control);
 151         mutex_unlock(&data->update_lock);
 152         return count;
 153 }
 154
 155 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
 156                    show_out0_enable, set_out0_enable);
 157
 158 static struct attribute *pcf8591_attributes[] = {
 159         &dev_attr_out0_enable.attr,
 160         &dev_attr_out0_output.attr,
 161         &dev_attr_in0_input.attr,
 162         &dev_attr_in1_input.attr,
 163         NULL
 164 };
 165
 166 static const struct attribute_group pcf8591_attr_group = {
 167         .attrs = pcf8591_attributes,
 168 };
 169
 170 static struct attribute *pcf8591_attributes_opt[] = {
 171         &dev_attr_in2_input.attr,
 172         &dev_attr_in3_input.attr,
 173         NULL
 174 };
 175
 176 static const struct attribute_group pcf8591_attr_group_opt = {
 177         .attrs = pcf8591_attributes_opt,
 178 };
 179
 180 /*
 181  * Real code
 182  */
 183 static int pcf8591_attach_adapter(struct i2c_adapter *adapter)
 184 {
 185         return i2c_probe(adapter, &addr_data, pcf8591_detect);
 186 }
 187
 188 /* This function is called by i2c_probe */
 189 static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind)
 190 {
 191         struct i2c_client *new_client;
 192         struct pcf8591_data *data;
 193         int err = 0;
 194
 195         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
 196                                      | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 197                 goto exit;
 198
 199         /* OK. For now, we presume we have a valid client. We now create the
 200            client structure, even though we cannot fill it completely yet. */
 201         if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
 202                 err = -ENOMEM;
 203                 goto exit;
 204         }
 205
 206         new_client = &data->client;
 207         i2c_set_clientdata(new_client, data);
 208         new_client->addr = address;
 209         new_client->adapter = adapter;
 210         new_client->driver = &pcf8591_driver;
 211         new_client->flags = 0;
 212
 213         /* Now, we would do the remaining detection. But the PCF8591 is plainly
 214            impossible to detect! Stupid chip. */
 215
 216         /* Determine the chip type - only one kind supported! */
 217         if (kind <= 0)
 218                 kind = pcf8591;
 219
 220         /* Fill in the remaining client fields and put it into the global
 221            list */
 222         strlcpy(new_client->name, "pcf8591", I2C_NAME_SIZE);
 223         mutex_init(&data->update_lock);
 224
 225         /* Tell the I2C layer a new client has arrived */
 226         if ((err = i2c_attach_client(new_client)))
 227                 goto exit_kfree;
 228
 229         /* Initialize the PCF8591 chip */
 230         pcf8591_init_client(new_client);
 231
 232         /* Register sysfs hooks */
 233         err = sysfs_create_group(&new_client->dev.kobj, &pcf8591_attr_group);
 234         if (err)
 235                 goto exit_detach;
 236
 237         /* Register input2 if not in "two differential inputs" mode */
 238         if (input_mode != 3) {
 239                 if ((err = device_create_file(&new_client->dev,
 240                                               &dev_attr_in2_input)))
 241                         goto exit_sysfs_remove;
 242         }
 243
 244         /* Register input3 only in "four single ended inputs" mode */
 245         if (input_mode == 0) {
 246                 if ((err = device_create_file(&new_client->dev,
 247                                               &dev_attr_in3_input)))
 248                         goto exit_sysfs_remove;
 249         }
 250
 251         return 0;
 252
 253 exit_sysfs_remove:
 254         sysfs_remove_group(&new_client->dev.kobj, &pcf8591_attr_group_opt);
 255         sysfs_remove_group(&new_client->dev.kobj, &pcf8591_attr_group);
 256 exit_detach:
 257         i2c_detach_client(new_client);
 258 exit_kfree:
 259         kfree(data);
 260 exit:
 261         return err;
 262 }
 263
 264 static int pcf8591_detach_client(struct i2c_client *client)
 265 {
 266         int err;
 267
 268         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
 269         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 270
 271         if ((err = i2c_detach_client(client)))
 272                 return err;
 273
 274         kfree(i2c_get_clientdata(client));
 275         return 0;
 276 }
 277
 278 /* Called when we have found a new PCF8591. */
 279 static void pcf8591_init_client(struct i2c_client *client)
 280 {
 281         struct pcf8591_data *data = i2c_get_clientdata(client);
 282         data->control = PCF8591_INIT_CONTROL;
 283         data->aout = PCF8591_INIT_AOUT;
 284
 285         i2c_smbus_write_byte_data(client, data->control, data->aout);
 286
 287         /* The first byte transmitted contains the conversion code of the
 288            previous read cycle. FLUSH IT! */
 289         i2c_smbus_read_byte(client);
 290 }
 291
 292 static int pcf8591_read_channel(struct device *dev, int channel)
 293 {
 294         u8 value;
 295         struct i2c_client *client = to_i2c_client(dev);
 296         struct pcf8591_data *data = i2c_get_clientdata(client);
 297
 298         mutex_lock(&data->update_lock);
 299
 300         if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
 301                 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
 302                               | channel;
 303                 i2c_smbus_write_byte(client, data->control);
 304
 305                 /* The first byte transmitted contains the conversion code of
 306                    the previous read cycle. FLUSH IT! */
 307                 i2c_smbus_read_byte(client);
 308         }
 309         value = i2c_smbus_read_byte(client);
 310
 311         mutex_unlock(&data->update_lock);
 312
 313         if ((channel == 2 && input_mode == 2) ||
 314             (channel != 3 && (input_mode == 1 || input_mode == 3)))
 315                 return (10 * REG_TO_SIGNED(value));
 316         else
 317                 return (10 * value);
 318 }
 319
 320 static int __init pcf8591_init(void)
 321 {
 322         if (input_mode < 0 || input_mode > 3) {
 323                 printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
 324                        input_mode);
 325                 input_mode = 0;
 326         }
 327         return i2c_add_driver(&pcf8591_driver);
 328 }
 329
 330 static void __exit pcf8591_exit(void)
 331 {
 332         i2c_del_driver(&pcf8591_driver);
 333 }
 334
 335 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
 336 MODULE_DESCRIPTION("PCF8591 driver");
 337 MODULE_LICENSE("GPL");
 338
 339 module_init(pcf8591_init);
 340 module_exit(pcf8591_exit);