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