drivers/i2c/chips/pcf8591.c

   1 /*
   2     pcf8591.c - Part of lm_sensors, Linux kernel modules for hardware
   3                 monitoring
   4     Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
   5     Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
   6     the help of Jean Delvare <khali@linux-fr.org>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25 #include <linux/slab.h>
  26 #include <linux/i2c.h>
  27 #include <linux/mutex.h>
  28
  29 /* Addresses to scan */
  30 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  31                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  32
  33 /* Insmod parameters */
  34 I2C_CLIENT_INSMOD_1(pcf8591);
  35
  36 static int input_mode;
  37 module_param(input_mode, int, 0);
  38 MODULE_PARM_DESC(input_mode,
  39         "Analog input mode:\n"
  40         " 0 = four single ended inputs\n"
  41         " 1 = three differential inputs\n"
  42         " 2 = single ended and differential mixed\n"
  43         " 3 = two differential inputs\n");
  44
  45 /* The PCF8591 control byte
  46       7    6    5    4    3    2    1    0
  47    |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */
  48
  49 /* Analog Output Enable Flag (analog output active if 1) */
  50 #define PCF8591_CONTROL_AOEF            0x40
  51
  52 /* Analog Input Programming
  53    0x00 = four single ended inputs
  54    0x10 = three differential inputs
  55    0x20 = single ended and differential mixed
  56    0x30 = two differential inputs */
  57 #define PCF8591_CONTROL_AIP_MASK        0x30
  58
  59 /* Autoincrement Flag (switch on if 1) */
  60 #define PCF8591_CONTROL_AINC            0x04
  61
  62 /* Channel selection
  63    0x00 = channel 0
  64    0x01 = channel 1
  65    0x02 = channel 2
  66    0x03 = channel 3 */
  67 #define PCF8591_CONTROL_AICH_MASK       0x03
  68
  69 /* Initial values */
  70 #define PCF8591_INIT_CONTROL    ((input_mode << 4) | PCF8591_CONTROL_AOEF)
  71 #define PCF8591_INIT_AOUT       0       /* DAC out = 0 */
  72
  73 /* Conversions */
  74 #define REG_TO_SIGNED(reg)      (((reg) & 0x80)?((reg) - 256):(reg))
  75
  76 struct pcf8591_data {
  77         struct i2c_client client;
  78         struct mutex update_lock;
  79
  80         u8 control;
  81         u8 aout;
  82 };
  83
  84 static int pcf8591_attach_adapter(struct i2c_adapter *adapter);
  85 static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind);
  86 static int pcf8591_detach_client(struct i2c_client *client);
  87 static void pcf8591_init_client(struct i2c_client *client);
  88 static int pcf8591_read_channel(struct device *dev, int channel);
  89
  90 /* This is the driver that will be inserted */
  91 static struct i2c_driver pcf8591_driver = {
  92         .driver = {
  93                 .name   = "pcf8591",
  94         },
  95         .id             = I2C_DRIVERID_PCF8591,
  96         .attach_adapter = pcf8591_attach_adapter,
  97         .detach_client  = pcf8591_detach_client,
  98 };
  99
 100 /* following are the sysfs callback functions */
 101 #define show_in_channel(channel)                                        \
 102 static ssize_t show_in##channel##_input(struct device *dev, struct device_attribute *attr, char *buf)   \
 103 {                                                                       \
 104         return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
 105 }                                                                       \
 106 static DEVICE_ATTR(in##channel##_input, S_IRUGO,                        \
 107                    show_in##channel##_input, NULL);
 108
 109 show_in_channel(0);
 110 show_in_channel(1);
 111 show_in_channel(2);
 112 show_in_channel(3);
 113
 114 static ssize_t show_out0_ouput(struct device *dev, struct device_attribute *attr, char *buf)
 115 {
 116         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 117         return sprintf(buf, "%d\n", data->aout * 10);
 118 }
 119
 120 static ssize_t set_out0_output(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 121 {
 122         unsigned int value;
 123         struct i2c_client *client = to_i2c_client(dev);
 124         struct pcf8591_data *data = i2c_get_clientdata(client);
 125         if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
 126                 data->aout = value;
 127                 i2c_smbus_write_byte_data(client, data->control, data->aout);
 128                 return count;
 129         }
 130         return -EINVAL;
 131 }
 132
 133 static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
 134                    show_out0_ouput, set_out0_output);
 135
 136 static ssize_t show_out0_enable(struct device *dev, struct device_attribute *attr, char *buf)
 137 {
 138         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 139         return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
 140 }
 141
 142 static ssize_t set_out0_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 143 {
 144         struct i2c_client *client = to_i2c_client(dev);
 145         struct pcf8591_data *data = i2c_get_clientdata(client);
 146         unsigned long val = simple_strtoul(buf, NULL, 10);
 147
 148         mutex_lock(&data->update_lock);
 149         if (val)
 150                 data->control |= PCF8591_CONTROL_AOEF;
 151         else
 152                 data->control &= ~PCF8591_CONTROL_AOEF;
 153         i2c_smbus_write_byte(client, data->control);
 154         mutex_unlock(&data->update_lock);
 155         return count;
 156 }
 157
 158 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
 159                    show_out0_enable, set_out0_enable);
 160
 161 static struct attribute *pcf8591_attributes[] = {
 162         &dev_attr_out0_enable.attr,
 163         &dev_attr_out0_output.attr,
 164         &dev_attr_in0_input.attr,
 165         &dev_attr_in1_input.attr,
 166         NULL
 167 };
 168
 169 static const struct attribute_group pcf8591_attr_group = {
 170         .attrs = pcf8591_attributes,
 171 };
 172
 173 static struct attribute *pcf8591_attributes_opt[] = {
 174         &dev_attr_in2_input.attr,
 175         &dev_attr_in3_input.attr,
 176         NULL
 177 };
 178
 179 static const struct attribute_group pcf8591_attr_group_opt = {
 180         .attrs = pcf8591_attributes_opt,
 181 };
 182
 183 /*
 184  * Real code
 185  */
 186 static int pcf8591_attach_adapter(struct i2c_adapter *adapter)
 187 {
 188         return i2c_probe(adapter, &addr_data, pcf8591_detect);
 189 }
 190
 191 /* This function is called by i2c_probe */
 192 static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind)
 193 {
 194         struct i2c_client *new_client;
 195         struct pcf8591_data *data;
 196         int err = 0;
 197
 198         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
 199                                      | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 200                 goto exit;
 201
 202         /* OK. For now, we presume we have a valid client. We now create the
 203            client structure, even though we cannot fill it completely yet. */
 204         if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
 205                 err = -ENOMEM;
 206                 goto exit;
 207         }
 208
 209         new_client = &data->client;
 210         i2c_set_clientdata(new_client, data);
 211         new_client->addr = address;
 212         new_client->adapter = adapter;
 213         new_client->driver = &pcf8591_driver;
 214         new_client->flags = 0;
 215
 216         /* Now, we would do the remaining detection. But the PCF8591 is plainly
 217            impossible to detect! Stupid chip. */
 218
 219         /* Determine the chip type - only one kind supported! */
 220         if (kind <= 0)
 221                 kind = pcf8591;
 222
 223         /* Fill in the remaining client fields and put it into the global
 224            list */
 225         strlcpy(new_client->name, "pcf8591", I2C_NAME_SIZE);
 226         mutex_init(&data->update_lock);
 227
 228         /* Tell the I2C layer a new client has arrived */
 229         if ((err = i2c_attach_client(new_client)))
 230                 goto exit_kfree;
 231
 232         /* Initialize the PCF8591 chip */
 233         pcf8591_init_client(new_client);
 234
 235         /* Register sysfs hooks */
 236         err = sysfs_create_group(&new_client->dev.kobj, &pcf8591_attr_group);
 237         if (err)
 238                 goto exit_detach;
 239
 240         /* Register input2 if not in "two differential inputs" mode */
 241         if (input_mode != 3) {
 242                 if ((err = device_create_file(&new_client->dev,
 243                                               &dev_attr_in2_input)))
 244                         goto exit_sysfs_remove;
 245         }
 246
 247         /* Register input3 only in "four single ended inputs" mode */
 248         if (input_mode == 0) {
 249                 if ((err = device_create_file(&new_client->dev,
 250                                               &dev_attr_in3_input)))
 251                         goto exit_sysfs_remove;
 252         }
 253
 254         return 0;
 255
 256 exit_sysfs_remove:
 257         sysfs_remove_group(&new_client->dev.kobj, &pcf8591_attr_group_opt);
 258         sysfs_remove_group(&new_client->dev.kobj, &pcf8591_attr_group);
 259 exit_detach:
 260         i2c_detach_client(new_client);
 261 exit_kfree:
 262         kfree(data);
 263 exit:
 264         return err;
 265 }
 266
 267 static int pcf8591_detach_client(struct i2c_client *client)
 268 {
 269         int err;
 270
 271         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
 272         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 273
 274         if ((err = i2c_detach_client(client)))
 275                 return err;
 276
 277         kfree(i2c_get_clientdata(client));
 278         return 0;
 279 }
 280
 281 /* Called when we have found a new PCF8591. */
 282 static void pcf8591_init_client(struct i2c_client *client)
 283 {
 284         struct pcf8591_data *data = i2c_get_clientdata(client);
 285         data->control = PCF8591_INIT_CONTROL;
 286         data->aout = PCF8591_INIT_AOUT;
 287
 288         i2c_smbus_write_byte_data(client, data->control, data->aout);
 289
 290         /* The first byte transmitted contains the conversion code of the
 291            previous read cycle. FLUSH IT! */
 292         i2c_smbus_read_byte(client);
 293 }
 294
 295 static int pcf8591_read_channel(struct device *dev, int channel)
 296 {
 297         u8 value;
 298         struct i2c_client *client = to_i2c_client(dev);
 299         struct pcf8591_data *data = i2c_get_clientdata(client);
 300
 301         mutex_lock(&data->update_lock);
 302
 303         if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
 304                 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
 305                               | channel;
 306                 i2c_smbus_write_byte(client, data->control);
 307
 308                 /* The first byte transmitted contains the conversion code of
 309                    the previous read cycle. FLUSH IT! */
 310                 i2c_smbus_read_byte(client);
 311         }
 312         value = i2c_smbus_read_byte(client);
 313
 314         mutex_unlock(&data->update_lock);
 315
 316         if ((channel == 2 && input_mode == 2) ||
 317             (channel != 3 && (input_mode == 1 || input_mode == 3)))
 318                 return (10 * REG_TO_SIGNED(value));
 319         else
 320                 return (10 * value);
 321 }
 322
 323 static int __init pcf8591_init(void)
 324 {
 325         if (input_mode < 0 || input_mode > 3) {
 326                 printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
 327                        input_mode);
 328                 input_mode = 0;
 329         }
 330         return i2c_add_driver(&pcf8591_driver);
 331 }
 332
 333 static void __exit pcf8591_exit(void)
 334 {
 335         i2c_del_driver(&pcf8591_driver);
 336 }
 337
 338 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
 339 MODULE_DESCRIPTION("PCF8591 driver");
 340 MODULE_LICENSE("GPL");
 341
 342 module_init(pcf8591_init);
 343 module_exit(pcf8591_exit);