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