drivers/hwmon/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
  33 static int input_mode;
  34 module_param(input_mode, int, 0);
  35 MODULE_PARM_DESC(input_mode,
  36         "Analog input mode:\n"
  37         " 0 = four single ended inputs\n"
  38         " 1 = three differential inputs\n"
  39         " 2 = single ended and differential mixed\n"
  40         " 3 = two differential inputs\n");
  41
  42 /* The PCF8591 control byte
  43       7    6    5    4    3    2    1    0
  44    |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */
  45
  46 /* Analog Output Enable Flag (analog output active if 1) */
  47 #define PCF8591_CONTROL_AOEF            0x40
  48
  49 /* Analog Input Programming
  50    0x00 = four single ended inputs
  51    0x10 = three differential inputs
  52    0x20 = single ended and differential mixed
  53    0x30 = two differential inputs */
  54 #define PCF8591_CONTROL_AIP_MASK        0x30
  55
  56 /* Autoincrement Flag (switch on if 1) */
  57 #define PCF8591_CONTROL_AINC            0x04
  58
  59 /* Channel selection
  60    0x00 = channel 0
  61    0x01 = channel 1
  62    0x02 = channel 2
  63    0x03 = channel 3 */
  64 #define PCF8591_CONTROL_AICH_MASK       0x03
  65
  66 /* Initial values */
  67 #define PCF8591_INIT_CONTROL    ((input_mode << 4) | PCF8591_CONTROL_AOEF)
  68 #define PCF8591_INIT_AOUT       0       /* DAC out = 0 */
  69
  70 /* Conversions */
  71 #define REG_TO_SIGNED(reg)      (((reg) & 0x80)?((reg) - 256):(reg))
  72
  73 struct pcf8591_data {
  74         struct mutex update_lock;
  75
  76         u8 control;
  77         u8 aout;
  78 };
  79
  80 static void pcf8591_init_client(struct i2c_client *client);
  81 static int pcf8591_read_channel(struct device *dev, int channel);
  82
  83 /* following are the sysfs callback functions */
  84 #define show_in_channel(channel)                                        \
  85 static ssize_t show_in##channel##_input(struct device *dev, struct device_attribute *attr, char *buf)   \
  86 {                                                                       \
  87         return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
  88 }                                                                       \
  89 static DEVICE_ATTR(in##channel##_input, S_IRUGO,                        \
  90                    show_in##channel##_input, NULL);
  91
  92 show_in_channel(0);
  93 show_in_channel(1);
  94 show_in_channel(2);
  95 show_in_channel(3);
  96
  97 static ssize_t show_out0_ouput(struct device *dev, struct device_attribute *attr, char *buf)
  98 {
  99         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 100         return sprintf(buf, "%d\n", data->aout * 10);
 101 }
 102
 103 static ssize_t set_out0_output(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 104 {
 105         unsigned int value;
 106         struct i2c_client *client = to_i2c_client(dev);
 107         struct pcf8591_data *data = i2c_get_clientdata(client);
 108         if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
 109                 data->aout = value;
 110                 i2c_smbus_write_byte_data(client, data->control, data->aout);
 111                 return count;
 112         }
 113         return -EINVAL;
 114 }
 115
 116 static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
 117                    show_out0_ouput, set_out0_output);
 118
 119 static ssize_t show_out0_enable(struct device *dev, struct device_attribute *attr, char *buf)
 120 {
 121         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 122         return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
 123 }
 124
 125 static ssize_t set_out0_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 126 {
 127         struct i2c_client *client = to_i2c_client(dev);
 128         struct pcf8591_data *data = i2c_get_clientdata(client);
 129         unsigned long val = simple_strtoul(buf, NULL, 10);
 130
 131         mutex_lock(&data->update_lock);
 132         if (val)
 133                 data->control |= PCF8591_CONTROL_AOEF;
 134         else
 135                 data->control &= ~PCF8591_CONTROL_AOEF;
 136         i2c_smbus_write_byte(client, data->control);
 137         mutex_unlock(&data->update_lock);
 138         return count;
 139 }
 140
 141 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
 142                    show_out0_enable, set_out0_enable);
 143
 144 static struct attribute *pcf8591_attributes[] = {
 145         &dev_attr_out0_enable.attr,
 146         &dev_attr_out0_output.attr,
 147         &dev_attr_in0_input.attr,
 148         &dev_attr_in1_input.attr,
 149         NULL
 150 };
 151
 152 static const struct attribute_group pcf8591_attr_group = {
 153         .attrs = pcf8591_attributes,
 154 };
 155
 156 static struct attribute *pcf8591_attributes_opt[] = {
 157         &dev_attr_in2_input.attr,
 158         &dev_attr_in3_input.attr,
 159         NULL
 160 };
 161
 162 static const struct attribute_group pcf8591_attr_group_opt = {
 163         .attrs = pcf8591_attributes_opt,
 164 };
 165
 166 /*
 167  * Real code
 168  */
 169
 170 /* Return 0 if detection is successful, -ENODEV otherwise */
 171 static int pcf8591_detect(struct i2c_client *client,
 172                           struct i2c_board_info *info)
 173 {
 174         struct i2c_adapter *adapter = client->adapter;
 175
 176         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
 177                                      | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 178                 return -ENODEV;
 179
 180         /* Now, we would do the remaining detection. But the PCF8591 is plainly
 181            impossible to detect! Stupid chip. */
 182
 183         strlcpy(info->type, "pcf8591", I2C_NAME_SIZE);
 184
 185         return 0;
 186 }
 187
 188 static int pcf8591_probe(struct i2c_client *client,
 189                          const struct i2c_device_id *id)
 190 {
 191         struct pcf8591_data *data;
 192         int err;
 193
 194         if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
 195                 err = -ENOMEM;
 196                 goto exit;
 197         }
 198
 199         i2c_set_clientdata(client, data);
 200         mutex_init(&data->update_lock);
 201
 202         /* Initialize the PCF8591 chip */
 203         pcf8591_init_client(client);
 204
 205         /* Register sysfs hooks */
 206         err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
 207         if (err)
 208                 goto exit_kfree;
 209
 210         /* Register input2 if not in "two differential inputs" mode */
 211         if (input_mode != 3) {
 212                 if ((err = device_create_file(&client->dev,
 213                                               &dev_attr_in2_input)))
 214                         goto exit_sysfs_remove;
 215         }
 216
 217         /* Register input3 only in "four single ended inputs" mode */
 218         if (input_mode == 0) {
 219                 if ((err = device_create_file(&client->dev,
 220                                               &dev_attr_in3_input)))
 221                         goto exit_sysfs_remove;
 222         }
 223
 224         return 0;
 225
 226 exit_sysfs_remove:
 227         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
 228         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 229 exit_kfree:
 230         kfree(data);
 231 exit:
 232         return err;
 233 }
 234
 235 static int pcf8591_remove(struct i2c_client *client)
 236 {
 237         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
 238         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 239         kfree(i2c_get_clientdata(client));
 240         return 0;
 241 }
 242
 243 /* Called when we have found a new PCF8591. */
 244 static void pcf8591_init_client(struct i2c_client *client)
 245 {
 246         struct pcf8591_data *data = i2c_get_clientdata(client);
 247         data->control = PCF8591_INIT_CONTROL;
 248         data->aout = PCF8591_INIT_AOUT;
 249
 250         i2c_smbus_write_byte_data(client, data->control, data->aout);
 251
 252         /* The first byte transmitted contains the conversion code of the
 253            previous read cycle. FLUSH IT! */
 254         i2c_smbus_read_byte(client);
 255 }
 256
 257 static int pcf8591_read_channel(struct device *dev, int channel)
 258 {
 259         u8 value;
 260         struct i2c_client *client = to_i2c_client(dev);
 261         struct pcf8591_data *data = i2c_get_clientdata(client);
 262
 263         mutex_lock(&data->update_lock);
 264
 265         if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
 266                 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
 267                               | channel;
 268                 i2c_smbus_write_byte(client, data->control);
 269
 270                 /* The first byte transmitted contains the conversion code of
 271                    the previous read cycle. FLUSH IT! */
 272                 i2c_smbus_read_byte(client);
 273         }
 274         value = i2c_smbus_read_byte(client);
 275
 276         mutex_unlock(&data->update_lock);
 277
 278         if ((channel == 2 && input_mode == 2) ||
 279             (channel != 3 && (input_mode == 1 || input_mode == 3)))
 280                 return (10 * REG_TO_SIGNED(value));
 281         else
 282                 return (10 * value);
 283 }
 284
 285 static const struct i2c_device_id pcf8591_id[] = {
 286         { "pcf8591", 0 },
 287         { }
 288 };
 289 MODULE_DEVICE_TABLE(i2c, pcf8591_id);
 290
 291 static struct i2c_driver pcf8591_driver = {
 292         .driver = {
 293                 .name   = "pcf8591",
 294         },
 295         .probe          = pcf8591_probe,
 296         .remove         = pcf8591_remove,
 297         .id_table       = pcf8591_id,
 298
 299         .class          = I2C_CLASS_HWMON,      /* Nearest choice */
 300         .detect         = pcf8591_detect,
 301         .address_list   = normal_i2c,
 302 };
 303
 304 static int __init pcf8591_init(void)
 305 {
 306         if (input_mode < 0 || input_mode > 3) {
 307                 printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
 308                        input_mode);
 309                 input_mode = 0;
 310         }
 311         return i2c_add_driver(&pcf8591_driver);
 312 }
 313
 314 static void __exit pcf8591_exit(void)
 315 {
 316         i2c_del_driver(&pcf8591_driver);
 317 }
 318
 319 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
 320 MODULE_DESCRIPTION("PCF8591 driver");
 321 MODULE_LICENSE("GPL");
 322
 323 module_init(pcf8591_init);
 324 module_exit(pcf8591_exit);