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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  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 #include <linux/err.h>
  29 #include <linux/hwmon.h>
  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 /*
  43  * The PCF8591 control byte
  44  *      7    6    5    4    3    2    1    0
  45  *   |  0 |AOEF|   AIP   |  0 |AINC|  AICH   |
  46  */
  47
  48 /* Analog Output Enable Flag (analog output active if 1) */
  49 #define PCF8591_CONTROL_AOEF            0x40
  50
  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  */
  58 #define PCF8591_CONTROL_AIP_MASK        0x30
  59
  60 /* Autoincrement Flag (switch on if 1) */
  61 #define PCF8591_CONTROL_AINC            0x04
  62
  63 /*
  64  * Channel selection
  65  * 0x00 = channel 0
  66  * 0x01 = channel 1
  67  * 0x02 = channel 2
  68  * 0x03 = channel 3
  69  */
  70 #define PCF8591_CONTROL_AICH_MASK       0x03
  71
  72 /* Initial values */
  73 #define PCF8591_INIT_CONTROL    ((input_mode << 4) | PCF8591_CONTROL_AOEF)
  74 #define PCF8591_INIT_AOUT       0       /* DAC out = 0 */
  75
  76 /* Conversions */
  77 #define REG_TO_SIGNED(reg)      (((reg) & 0x80) ? ((reg) - 256) : (reg))
  78
  79 struct pcf8591_data {
  80         struct device *hwmon_dev;
  81         struct mutex update_lock;
  82
  83         u8 control;
  84         u8 aout;
  85 };
  86
  87 static void pcf8591_init_client(struct i2c_client *client);
  88 static int pcf8591_read_channel(struct device *dev, int channel);
  89
  90 /* following are the sysfs callback functions */
  91 #define show_in_channel(channel)                                        \
  92 static ssize_t show_in##channel##_input(struct device *dev,             \
  93                                         struct device_attribute *attr,  \
  94                                         char *buf)                      \
  95 {                                                                       \
  96         return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
  97 }                                                                       \
  98 static DEVICE_ATTR(in##channel##_input, S_IRUGO,                        \
  99                    show_in##channel##_input, NULL);
 100
 101 show_in_channel(0);
 102 show_in_channel(1);
 103 show_in_channel(2);
 104 show_in_channel(3);
 105
 106 static ssize_t show_out0_ouput(struct device *dev,
 107                                struct device_attribute *attr, char *buf)
 108 {
 109         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 110         return sprintf(buf, "%d\n", data->aout * 10);
 111 }
 112
 113 static ssize_t set_out0_output(struct device *dev,
 114                                struct device_attribute *attr,
 115                                const char *buf, size_t count)
 116 {
 117         unsigned long val;
 118         struct i2c_client *client = to_i2c_client(dev);
 119         struct pcf8591_data *data = i2c_get_clientdata(client);
 120         int err;
 121
 122         err = kstrtoul(buf, 10, &val);
 123         if (err)
 124                 return err;
 125
 126         val /= 10;
 127         if (val > 255)
 128                 return -EINVAL;
 129
 130         data->aout = val;
 131         i2c_smbus_write_byte_data(client, data->control, data->aout);
 132         return count;
 133 }
 134
 135 static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
 136                    show_out0_ouput, set_out0_output);
 137
 138 static ssize_t show_out0_enable(struct device *dev,
 139                                 struct device_attribute *attr, char *buf)
 140 {
 141         struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
 142         return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
 143 }
 144
 145 static ssize_t set_out0_enable(struct device *dev,
 146                                struct device_attribute *attr,
 147                                const char *buf, size_t count)
 148 {
 149         struct i2c_client *client = to_i2c_client(dev);
 150         struct pcf8591_data *data = i2c_get_clientdata(client);
 151         unsigned long val;
 152         int err;
 153
 154         err = kstrtoul(buf, 10, &val);
 155         if (err)
 156                 return err;
 157
 158         mutex_lock(&data->update_lock);
 159         if (val)
 160                 data->control |= PCF8591_CONTROL_AOEF;
 161         else
 162                 data->control &= ~PCF8591_CONTROL_AOEF;
 163         i2c_smbus_write_byte(client, data->control);
 164         mutex_unlock(&data->update_lock);
 165         return count;
 166 }
 167
 168 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
 169                    show_out0_enable, set_out0_enable);
 170
 171 static struct attribute *pcf8591_attributes[] = {
 172         &dev_attr_out0_enable.attr,
 173         &dev_attr_out0_output.attr,
 174         &dev_attr_in0_input.attr,
 175         &dev_attr_in1_input.attr,
 176         NULL
 177 };
 178
 179 static const struct attribute_group pcf8591_attr_group = {
 180         .attrs = pcf8591_attributes,
 181 };
 182
 183 static struct attribute *pcf8591_attributes_opt[] = {
 184         &dev_attr_in2_input.attr,
 185         &dev_attr_in3_input.attr,
 186         NULL
 187 };
 188
 189 static const struct attribute_group pcf8591_attr_group_opt = {
 190         .attrs = pcf8591_attributes_opt,
 191 };
 192
 193 /*
 194  * Real code
 195  */
 196
 197 static int pcf8591_probe(struct i2c_client *client,
 198                          const struct i2c_device_id *id)
 199 {
 200         struct pcf8591_data *data;
 201         int err;
 202
 203         data = devm_kzalloc(&client->dev, sizeof(struct pcf8591_data),
 204                             GFP_KERNEL);
 205         if (!data)
 206                 return -ENOMEM;
 207
 208         i2c_set_clientdata(client, data);
 209         mutex_init(&data->update_lock);
 210
 211         /* Initialize the PCF8591 chip */
 212         pcf8591_init_client(client);
 213
 214         /* Register sysfs hooks */
 215         err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
 216         if (err)
 217                 return err;
 218
 219         /* Register input2 if not in "two differential inputs" mode */
 220         if (input_mode != 3) {
 221                 err = device_create_file(&client->dev, &dev_attr_in2_input);
 222                 if (err)
 223                         goto exit_sysfs_remove;
 224         }
 225
 226         /* Register input3 only in "four single ended inputs" mode */
 227         if (input_mode == 0) {
 228                 err = device_create_file(&client->dev, &dev_attr_in3_input);
 229                 if (err)
 230                         goto exit_sysfs_remove;
 231         }
 232
 233         data->hwmon_dev = hwmon_device_register(&client->dev);
 234         if (IS_ERR(data->hwmon_dev)) {
 235                 err = PTR_ERR(data->hwmon_dev);
 236                 goto exit_sysfs_remove;
 237         }
 238
 239         return 0;
 240
 241 exit_sysfs_remove:
 242         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
 243         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 244         return err;
 245 }
 246
 247 static int pcf8591_remove(struct i2c_client *client)
 248 {
 249         struct pcf8591_data *data = i2c_get_clientdata(client);
 250
 251         hwmon_device_unregister(data->hwmon_dev);
 252         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
 253         sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 254         return 0;
 255 }
 256
 257 /* Called when we have found a new PCF8591. */
 258 static void pcf8591_init_client(struct i2c_client *client)
 259 {
 260         struct pcf8591_data *data = i2c_get_clientdata(client);
 261         data->control = PCF8591_INIT_CONTROL;
 262         data->aout = PCF8591_INIT_AOUT;
 263
 264         i2c_smbus_write_byte_data(client, data->control, data->aout);
 265
 266         /*
 267          * The first byte transmitted contains the conversion code of the
 268          * previous read cycle. FLUSH IT!
 269          */
 270         i2c_smbus_read_byte(client);
 271 }
 272
 273 static int pcf8591_read_channel(struct device *dev, int channel)
 274 {
 275         u8 value;
 276         struct i2c_client *client = to_i2c_client(dev);
 277         struct pcf8591_data *data = i2c_get_clientdata(client);
 278
 279         mutex_lock(&data->update_lock);
 280
 281         if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
 282                 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
 283                               | channel;
 284                 i2c_smbus_write_byte(client, data->control);
 285
 286                 /*
 287                  * The first byte transmitted contains the conversion code of
 288                  * the previous read cycle. FLUSH IT!
 289                  */
 290                 i2c_smbus_read_byte(client);
 291         }
 292         value = i2c_smbus_read_byte(client);
 293
 294         mutex_unlock(&data->update_lock);
 295
 296         if ((channel == 2 && input_mode == 2) ||
 297             (channel != 3 && (input_mode == 1 || input_mode == 3)))
 298                 return 10 * REG_TO_SIGNED(value);
 299         else
 300                 return 10 * value;
 301 }
 302
 303 static const struct i2c_device_id pcf8591_id[] = {
 304         { "pcf8591", 0 },
 305         { }
 306 };
 307 MODULE_DEVICE_TABLE(i2c, pcf8591_id);
 308
 309 static struct i2c_driver pcf8591_driver = {
 310         .driver = {
 311                 .name   = "pcf8591",
 312         },
 313         .probe          = pcf8591_probe,
 314         .remove         = pcf8591_remove,
 315         .id_table       = pcf8591_id,
 316 };
 317
 318 static int __init pcf8591_init(void)
 319 {
 320         if (input_mode < 0 || input_mode > 3) {
 321                 pr_warn("invalid input_mode (%d)\n", input_mode);
 322                 input_mode = 0;
 323         }
 324         return i2c_add_driver(&pcf8591_driver);
 325 }
 326
 327 static void __exit pcf8591_exit(void)
 328 {
 329         i2c_del_driver(&pcf8591_driver);
 330 }
 331
 332 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
 333 MODULE_DESCRIPTION("PCF8591 driver");
 334 MODULE_LICENSE("GPL");
 335
 336 module_init(pcf8591_init);
 337 module_exit(pcf8591_exit);