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/i2c-sensor.h>
  28
  29 /* Addresses to scan */
  30 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  31                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  32 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
  33
  34 /* Insmod parameters */
  35 SENSORS_INSMOD_1(pcf8591);
  36
  37 static int input_mode;
  38 module_param(input_mode, int, 0);
  39 MODULE_PARM_DESC(input_mode,
  40         "Analog input mode:\n"
  41         " 0 = four single ended inputs\n"
  42         " 1 = three differential inputs\n"
  43         " 2 = single ended and differential mixed\n"
  44         " 3 = two differential inputs\n");
  45
  46 /* The PCF8591 control byte
  47       7    6    5    4    3    2    1    0
  48    |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */
  49
  50 /* Analog Output Enable Flag (analog output active if 1) */
  51 #define PCF8591_CONTROL_AOEF            0x40
  52
  53 /* Analog Input Programming
  54    0x00 = four single ended inputs
  55    0x10 = three differential inputs
  56    0x20 = single ended and differential mixed
  57    0x30 = two differential inputs */
  58 #define PCF8591_CONTROL_AIP_MASK        0x30
  59
  60 /* Autoincrement Flag (switch on if 1) */
  61 #define PCF8591_CONTROL_AINC            0x04
  62
  63 /* Channel selection
  64    0x00 = channel 0
  65    0x01 = channel 1
  66    0x02 = channel 2
  67    0x03 = channel 3 */
  68 #define PCF8591_CONTROL_AICH_MASK       0x03
  69
  70 /* Initial values */
  71 #define PCF8591_INIT_CONTROL    ((input_mode << 4) | PCF8591_CONTROL_AOEF)
  72 #define PCF8591_INIT_AOUT       0       /* DAC out = 0 */
  73
  74 /* Conversions */
  75 #define REG_TO_SIGNED(reg)      (((reg) & 0x80)?((reg) - 256):(reg))
  76
  77 struct pcf8591_data {
  78         struct i2c_client client;
  79         struct semaphore update_lock;
  80
  81         u8 control;
  82         u8 aout;
  83 };
  84
  85 static int pcf8591_attach_adapter(struct i2c_adapter *adapter);
  86 static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind);
  87 static int pcf8591_detach_client(struct i2c_client *client);
  88 static void pcf8591_init_client(struct i2c_client *client);
  89 static int pcf8591_read_channel(struct device *dev, int channel);
  90
  91 /* This is the driver that will be inserted */
  92 static struct i2c_driver pcf8591_driver = {
  93         .owner          = THIS_MODULE,
  94         .name           = "pcf8591",
  95         .id             = I2C_DRIVERID_PCF8591,
  96         .flags          = I2C_DF_NOTIFY,
  97         .attach_adapter = pcf8591_attach_adapter,
  98         .detach_client  = pcf8591_detach_client,
  99 };
 100
 101 /* following are the sysfs callback functions */
 102 #define show_in_channel(channel)                                        \
 103 static ssize_t show_in##channel##_input(struct device *dev, char *buf)  \
 104 {                                                                       \
 105         return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
 106 }                                                                       \
 107 static DEVICE_ATTR(in##channel##_input, S_IRUGO,                        \
 108                    show_in##channel##_input, NULL);
 109
 110 show_in_channel(0);
 111 show_in_channel(1);
 112 show_in_channel(2);
 113 show_in_channel(3);
 114
 115 static ssize_t show_out0_ouput(struct device *dev, char *buf)
 116 {
 117         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 118         return sprintf(buf, "%d\n", data->aout * 10);
 119 }
 120
 121 static ssize_t set_out0_output(struct device *dev, const char *buf, size_t count)
 122 {
 123         unsigned int value;
 124         struct i2c_client *client = to_i2c_client(dev);
 125         struct pcf8591_data *data = i2c_get_clientdata(client);
 126         if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
 127                 data->aout = value;
 128                 i2c_smbus_write_byte_data(client, data->control, data->aout);
 129                 return count;
 130         }
 131         return -EINVAL;
 132 }
 133
 134 static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
 135                    show_out0_ouput, set_out0_output);
 136
 137 static ssize_t show_out0_enable(struct device *dev, char *buf)
 138 {
 139         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 140         return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
 141 }
 142
 143 static ssize_t set_out0_enable(struct device *dev, const char *buf, size_t count)
 144 {
 145         struct i2c_client *client = to_i2c_client(dev);
 146         struct pcf8591_data *data = i2c_get_clientdata(client);
 147         unsigned long val = simple_strtoul(buf, NULL, 10);
 148
 149         down(&data->update_lock);
 150         if (val)
 151                 data->control |= PCF8591_CONTROL_AOEF;
 152         else
 153                 data->control &= ~PCF8591_CONTROL_AOEF;
 154         i2c_smbus_write_byte(client, data->control);
 155         up(&data->update_lock);
 156         return count;
 157 }
 158
 159 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
 160                    show_out0_enable, set_out0_enable);
 161
 162 /*
 163  * Real code
 164  */
 165 static int pcf8591_attach_adapter(struct i2c_adapter *adapter)
 166 {
 167         return i2c_detect(adapter, &addr_data, pcf8591_detect);
 168 }
 169
 170 /* This function is called by i2c_detect */
 171 int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind)
 172 {
 173         struct i2c_client *new_client;
 174         struct pcf8591_data *data;
 175         int err = 0;
 176
 177         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
 178                                      | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 179                 goto exit;
 180
 181         /* OK. For now, we presume we have a valid client. We now create the
 182            client structure, even though we cannot fill it completely yet. */
 183         if (!(data = kmalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
 184                 err = -ENOMEM;
 185                 goto exit;
 186         }
 187         memset(data, 0, sizeof(struct pcf8591_data));
 188
 189         new_client = &data->client;
 190         i2c_set_clientdata(new_client, data);
 191         new_client->addr = address;
 192         new_client->adapter = adapter;
 193         new_client->driver = &pcf8591_driver;
 194         new_client->flags = 0;
 195
 196         /* Now, we would do the remaining detection. But the PCF8591 is plainly
 197            impossible to detect! Stupid chip. */
 198
 199         /* Determine the chip type - only one kind supported! */
 200         if (kind <= 0)
 201                 kind = pcf8591;
 202
 203         /* Fill in the remaining client fields and put it into the global
 204            list */
 205         strlcpy(new_client->name, "pcf8591", I2C_NAME_SIZE);
 206         init_MUTEX(&data->update_lock);
 207
 208         /* Tell the I2C layer a new client has arrived */
 209         if ((err = i2c_attach_client(new_client)))
 210                 goto exit_kfree;
 211
 212         /* Initialize the PCF8591 chip */
 213         pcf8591_init_client(new_client);
 214
 215         /* Register sysfs hooks */
 216         device_create_file(&new_client->dev, &dev_attr_out0_enable);
 217         device_create_file(&new_client->dev, &dev_attr_out0_output);
 218         device_create_file(&new_client->dev, &dev_attr_in0_input);
 219         device_create_file(&new_client->dev, &dev_attr_in1_input);
 220
 221         /* Register input2 if not in "two differential inputs" mode */
 222         if (input_mode != 3 )
 223                 device_create_file(&new_client->dev, &dev_attr_in2_input);
 224
 225         /* Register input3 only in "four single ended inputs" mode */
 226         if (input_mode == 0)
 227                 device_create_file(&new_client->dev, &dev_attr_in3_input);
 228
 229         return 0;
 230
 231         /* OK, this is not exactly good programming practice, usually. But it is
 232            very code-efficient in this case. */
 233
 234 exit_kfree:
 235         kfree(data);
 236 exit:
 237         return err;
 238 }
 239
 240 static int pcf8591_detach_client(struct i2c_client *client)
 241 {
 242         int err;
 243
 244         if ((err = i2c_detach_client(client))) {
 245                 dev_err(&client->dev,
 246                         "Client deregistration failed, client not detached.\n");
 247                 return err;
 248         }
 249
 250         kfree(i2c_get_clientdata(client));
 251         return 0;
 252 }
 253
 254 /* Called when we have found a new PCF8591. */
 255 static void pcf8591_init_client(struct i2c_client *client)
 256 {
 257         struct pcf8591_data *data = i2c_get_clientdata(client);
 258         data->control = PCF8591_INIT_CONTROL;
 259         data->aout = PCF8591_INIT_AOUT;
 260
 261         i2c_smbus_write_byte_data(client, data->control, data->aout);
 262
 263         /* The first byte transmitted contains the conversion code of the
 264            previous read cycle. FLUSH IT! */
 265         i2c_smbus_read_byte(client);
 266 }
 267
 268 static int pcf8591_read_channel(struct device *dev, int channel)
 269 {
 270         u8 value;
 271         struct i2c_client *client = to_i2c_client(dev);
 272         struct pcf8591_data *data = i2c_get_clientdata(client);
 273
 274         down(&data->update_lock);
 275
 276         if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
 277                 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
 278                               | channel;
 279                 i2c_smbus_write_byte(client, data->control);
 280
 281                 /* The first byte transmitted contains the conversion code of
 282                    the previous read cycle. FLUSH IT! */
 283                 i2c_smbus_read_byte(client);
 284         }
 285         value = i2c_smbus_read_byte(client);
 286
 287         up(&data->update_lock);
 288
 289         if ((channel == 2 && input_mode == 2) ||
 290             (channel != 3 && (input_mode == 1 || input_mode == 3)))
 291                 return (10 * REG_TO_SIGNED(value));
 292         else
 293                 return (10 * value);
 294 }
 295
 296 static int __init pcf8591_init(void)
 297 {
 298         if (input_mode < 0 || input_mode > 3) {
 299                 printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
 300                        input_mode);
 301                 input_mode = 0;
 302         }
 303         return i2c_add_driver(&pcf8591_driver);
 304 }
 305
 306 static void __exit pcf8591_exit(void)
 307 {
 308         i2c_del_driver(&pcf8591_driver);
 309 }
 310
 311 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
 312 MODULE_DESCRIPTION("PCF8591 driver");
 313 MODULE_LICENSE("GPL");
 314
 315 module_init(pcf8591_init);
 316 module_exit(pcf8591_exit);