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[] = { I2C_CLIENT_END };
  31 static unsigned short normal_i2c_range[] = { 0x48, 0x4f, I2C_CLIENT_END };
  32 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
  33 static unsigned int normal_isa_range[] = { I2C_CLIENT_ISA_END };
  34
  35 /* Insmod parameters */
  36 SENSORS_INSMOD_1(pcf8591);
  37
  38 static int input_mode;
  39 module_param(input_mode, int, 0);
  40 MODULE_PARM_DESC(input_mode,
  41         "Analog input mode:\n"
  42         " 0 = four single ended inputs\n"
  43         " 1 = three differential inputs\n"
  44         " 2 = single ended and differential mixed\n"
  45         " 3 = two differential inputs\n");
  46
  47 /* The PCF8591 control byte
  48       7    6    5    4    3    2    1    0
  49    |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */
  50
  51 /* Analog Output Enable Flag (analog output active if 1) */
  52 #define PCF8591_CONTROL_AOEF            0x40
  53
  54 /* Analog Input Programming
  55    0x00 = four single ended inputs
  56    0x10 = three differential inputs
  57    0x20 = single ended and differential mixed
  58    0x30 = two differential inputs */
  59 #define PCF8591_CONTROL_AIP_MASK        0x30
  60
  61 /* Autoincrement Flag (switch on if 1) */
  62 #define PCF8591_CONTROL_AINC            0x04
  63
  64 /* Channel selection
  65    0x00 = channel 0
  66    0x01 = channel 1
  67    0x02 = channel 2
  68    0x03 = channel 3 */
  69 #define PCF8591_CONTROL_AICH_MASK       0x03
  70
  71 /* Initial values */
  72 #define PCF8591_INIT_CONTROL    ((input_mode << 4) | PCF8591_CONTROL_AOEF)
  73 #define PCF8591_INIT_AOUT       0       /* DAC out = 0 */
  74
  75 /* Conversions */
  76 #define REG_TO_SIGNED(reg)      (((reg) & 0x80)?((reg) - 256):(reg))
  77
  78 struct pcf8591_data {
  79         struct i2c_client client;
  80         struct semaphore update_lock;
  81
  82         u8 control;
  83         u8 aout;
  84 };
  85
  86 static int pcf8591_attach_adapter(struct i2c_adapter *adapter);
  87 static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind);
  88 static int pcf8591_detach_client(struct i2c_client *client);
  89 static void pcf8591_init_client(struct i2c_client *client);
  90 static int pcf8591_read_channel(struct device *dev, int channel);
  91
  92 /* This is the driver that will be inserted */
  93 static struct i2c_driver pcf8591_driver = {
  94         .owner          = THIS_MODULE,
  95         .name           = "pcf8591",
  96         .id             = I2C_DRIVERID_PCF8591,
  97         .flags          = I2C_DF_NOTIFY,
  98         .attach_adapter = pcf8591_attach_adapter,
  99         .detach_client  = pcf8591_detach_client,
 100 };
 101
 102 static int pcf8591_id = 0;
 103
 104 /* following are the sysfs callback functions */
 105 #define show_in_channel(channel)                                        \
 106 static ssize_t show_in##channel##_input(struct device *dev, char *buf)  \
 107 {                                                                       \
 108         return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
 109 }                                                                       \
 110 static DEVICE_ATTR(in##channel##_input, S_IRUGO,                        \
 111                    show_in##channel##_input, NULL);
 112
 113 show_in_channel(0);
 114 show_in_channel(1);
 115 show_in_channel(2);
 116 show_in_channel(3);
 117
 118 static ssize_t show_out0_ouput(struct device *dev, char *buf)
 119 {
 120         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 121         return sprintf(buf, "%d\n", data->aout * 10);
 122 }
 123
 124 static ssize_t set_out0_output(struct device *dev, const char *buf, size_t count)
 125 {
 126         unsigned int value;
 127         struct i2c_client *client = to_i2c_client(dev);
 128         struct pcf8591_data *data = i2c_get_clientdata(client);
 129         if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
 130                 data->aout = value;
 131                 i2c_smbus_write_byte_data(client, data->control, data->aout);
 132                 return count;
 133         }
 134         return -EINVAL;
 135 }
 136
 137 static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
 138                    show_out0_ouput, set_out0_output);
 139
 140 static ssize_t show_out0_enable(struct device *dev, char *buf)
 141 {
 142         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 143         return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
 144 }
 145
 146 static ssize_t set_out0_enable(struct device *dev, const char *buf, size_t count)
 147 {
 148         struct i2c_client *client = to_i2c_client(dev);
 149         struct pcf8591_data *data = i2c_get_clientdata(client);
 150         if (simple_strtoul(buf, NULL, 10))
 151                 data->control |= PCF8591_CONTROL_AOEF;
 152         else
 153                 data->control &= ~PCF8591_CONTROL_AOEF;
 154         i2c_smbus_write_byte(client, data->control);
 155         return count;
 156 }
 157
 158 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
 159                    show_out0_enable, set_out0_enable);
 160
 161 /*
 162  * Real code
 163  */
 164 static int pcf8591_attach_adapter(struct i2c_adapter *adapter)
 165 {
 166         return i2c_detect(adapter, &addr_data, pcf8591_detect);
 167 }
 168
 169 /* This function is called by i2c_detect */
 170 int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind)
 171 {
 172         struct i2c_client *new_client;
 173         struct pcf8591_data *data;
 174         int err = 0;
 175
 176         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
 177                                      | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 178                 goto exit;
 179
 180         /* OK. For now, we presume we have a valid client. We now create the
 181            client structure, even though we cannot fill it completely yet. */
 182         if (!(data = kmalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
 183                 err = -ENOMEM;
 184                 goto exit;
 185         }
 186         memset(data, 0, sizeof(struct pcf8591_data));
 187
 188         new_client = &data->client;
 189         i2c_set_clientdata(new_client, data);
 190         new_client->addr = address;
 191         new_client->adapter = adapter;
 192         new_client->driver = &pcf8591_driver;
 193         new_client->flags = 0;
 194
 195         /* Now, we would do the remaining detection. But the PCF8591 is plainly
 196            impossible to detect! Stupid chip. */
 197
 198         /* Determine the chip type - only one kind supported! */
 199         if (kind <= 0)
 200                 kind = pcf8591;
 201
 202         /* Fill in the remaining client fields and put it into the global
 203            list */
 204         strlcpy(new_client->name, "pcf8591", I2C_NAME_SIZE);
 205
 206         new_client->id = pcf8591_id++;
 207         init_MUTEX(&data->update_lock);
 208
 209         /* Tell the I2C layer a new client has arrived */
 210         if ((err = i2c_attach_client(new_client)))
 211                 goto exit_kfree;
 212
 213         /* Initialize the PCF8591 chip */
 214         pcf8591_init_client(new_client);
 215
 216         /* Register sysfs hooks */
 217         device_create_file(&new_client->dev, &dev_attr_out0_enable);
 218         device_create_file(&new_client->dev, &dev_attr_out0_output);
 219         device_create_file(&new_client->dev, &dev_attr_in0_input);
 220         device_create_file(&new_client->dev, &dev_attr_in1_input);
 221
 222         /* Register input2 if not in "two differential inputs" mode */
 223         if (input_mode != 3 )
 224                 device_create_file(&new_client->dev, &dev_attr_in2_input);
 225
 226         /* Register input3 only in "four single ended inputs" mode */
 227         if (input_mode == 0)
 228                 device_create_file(&new_client->dev, &dev_attr_in3_input);
 229
 230         return 0;
 231
 232         /* OK, this is not exactly good programming practice, usually. But it is
 233            very code-efficient in this case. */
 234
 235 exit_kfree:
 236         kfree(data);
 237 exit:
 238         return err;
 239 }
 240
 241 static int pcf8591_detach_client(struct i2c_client *client)
 242 {
 243         int err;
 244
 245         if ((err = i2c_detach_client(client))) {
 246                 dev_err(&client->dev,
 247                         "Client deregistration failed, client not detached.\n");
 248                 return err;
 249         }
 250
 251         kfree(i2c_get_clientdata(client));
 252         return 0;
 253 }
 254
 255 /* Called when we have found a new PCF8591. */
 256 static void pcf8591_init_client(struct i2c_client *client)
 257 {
 258         struct pcf8591_data *data = i2c_get_clientdata(client);
 259         data->control = PCF8591_INIT_CONTROL;
 260         data->aout = PCF8591_INIT_AOUT;
 261
 262         i2c_smbus_write_byte_data(client, data->control, data->aout);
 263
 264         /* The first byte transmitted contains the conversion code of the
 265            previous read cycle. FLUSH IT! */
 266         i2c_smbus_read_byte(client);
 267 }
 268
 269 static int pcf8591_read_channel(struct device *dev, int channel)
 270 {
 271         u8 value;
 272         struct i2c_client *client = to_i2c_client(dev);
 273         struct pcf8591_data *data = i2c_get_clientdata(client);
 274
 275         down(&data->update_lock);
 276
 277         if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
 278                 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
 279                               | channel;
 280                 i2c_smbus_write_byte(client, data->control);
 281
 282                 /* The first byte transmitted contains the conversion code of
 283                    the previous read cycle. FLUSH IT! */
 284                 i2c_smbus_read_byte(client);
 285         }
 286         value = i2c_smbus_read_byte(client);
 287
 288         up(&data->update_lock);
 289
 290         if ((channel == 2 && input_mode == 2) ||
 291             (channel != 3 && (input_mode == 1 || input_mode == 3)))
 292                 return (10 * REG_TO_SIGNED(value));
 293         else
 294                 return (10 * value);
 295 }
 296
 297 static int __init pcf8591_init(void)
 298 {
 299         if (input_mode < 0 || input_mode > 3) {
 300                 printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
 301                        input_mode);
 302                 input_mode = 0;
 303         }
 304         return i2c_add_driver(&pcf8591_driver);
 305 }
 306
 307 static void __exit pcf8591_exit(void)
 308 {
 309         i2c_del_driver(&pcf8591_driver);
 310 }
 311
 312 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
 313 MODULE_DESCRIPTION("PCF8591 driver");
 314 MODULE_LICENSE("GPL");
 315
 316 module_init(pcf8591_init);
 317 module_exit(pcf8591_exit);