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
  28 /* Addresses to scan */
  29 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  30                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  31
  32 /* Insmod parameters */
  33 I2C_CLIENT_INSMOD_1(pcf8591);
  34
  35 static int input_mode;
  36 module_param(input_mode, int, 0);
  37 MODULE_PARM_DESC(input_mode,
  38         "Analog input mode:\n"
  39         " 0 = four single ended inputs\n"
  40         " 1 = three differential inputs\n"
  41         " 2 = single ended and differential mixed\n"
  42         " 3 = two differential inputs\n");
  43
  44 /* The PCF8591 control byte
  45       7    6    5    4    3    2    1    0
  46    |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */
  47
  48 /* Analog Output Enable Flag (analog output active if 1) */
  49 #define PCF8591_CONTROL_AOEF            0x40
  50
  51 /* Analog Input Programming
  52    0x00 = four single ended inputs
  53    0x10 = three differential inputs
  54    0x20 = single ended and differential mixed
  55    0x30 = two differential inputs */
  56 #define PCF8591_CONTROL_AIP_MASK        0x30
  57
  58 /* Autoincrement Flag (switch on if 1) */
  59 #define PCF8591_CONTROL_AINC            0x04
  60
  61 /* Channel selection
  62    0x00 = channel 0
  63    0x01 = channel 1
  64    0x02 = channel 2
  65    0x03 = channel 3 */
  66 #define PCF8591_CONTROL_AICH_MASK       0x03
  67
  68 /* Initial values */
  69 #define PCF8591_INIT_CONTROL    ((input_mode << 4) | PCF8591_CONTROL_AOEF)
  70 #define PCF8591_INIT_AOUT       0       /* DAC out = 0 */
  71
  72 /* Conversions */
  73 #define REG_TO_SIGNED(reg)      (((reg) & 0x80)?((reg) - 256):(reg))
  74
  75 struct pcf8591_data {
  76         struct i2c_client client;
  77         struct semaphore update_lock;
  78
  79         u8 control;
  80         u8 aout;
  81 };
  82
  83 static int pcf8591_attach_adapter(struct i2c_adapter *adapter);
  84 static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind);
  85 static int pcf8591_detach_client(struct i2c_client *client);
  86 static void pcf8591_init_client(struct i2c_client *client);
  87 static int pcf8591_read_channel(struct device *dev, int channel);
  88
  89 /* This is the driver that will be inserted */
  90 static struct i2c_driver pcf8591_driver = {
  91         .owner          = THIS_MODULE,
  92         .name           = "pcf8591",
  93         .id             = I2C_DRIVERID_PCF8591,
  94         .flags          = I2C_DF_NOTIFY,
  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         down(&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         up(&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 /*
 161  * Real code
 162  */
 163 static int pcf8591_attach_adapter(struct i2c_adapter *adapter)
 164 {
 165         return i2c_probe(adapter, &addr_data, pcf8591_detect);
 166 }
 167
 168 /* This function is called by i2c_probe */
 169 static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind)
 170 {
 171         struct i2c_client *new_client;
 172         struct pcf8591_data *data;
 173         int err = 0;
 174
 175         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
 176                                      | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 177                 goto exit;
 178
 179         /* OK. For now, we presume we have a valid client. We now create the
 180            client structure, even though we cannot fill it completely yet. */
 181         if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
 182                 err = -ENOMEM;
 183                 goto exit;
 184         }
 185
 186         new_client = &data->client;
 187         i2c_set_clientdata(new_client, data);
 188         new_client->addr = address;
 189         new_client->adapter = adapter;
 190         new_client->driver = &pcf8591_driver;
 191         new_client->flags = 0;
 192
 193         /* Now, we would do the remaining detection. But the PCF8591 is plainly
 194            impossible to detect! Stupid chip. */
 195
 196         /* Determine the chip type - only one kind supported! */
 197         if (kind <= 0)
 198                 kind = pcf8591;
 199
 200         /* Fill in the remaining client fields and put it into the global
 201            list */
 202         strlcpy(new_client->name, "pcf8591", I2C_NAME_SIZE);
 203         init_MUTEX(&data->update_lock);
 204
 205         /* Tell the I2C layer a new client has arrived */
 206         if ((err = i2c_attach_client(new_client)))
 207                 goto exit_kfree;
 208
 209         /* Initialize the PCF8591 chip */
 210         pcf8591_init_client(new_client);
 211
 212         /* Register sysfs hooks */
 213         device_create_file(&new_client->dev, &dev_attr_out0_enable);
 214         device_create_file(&new_client->dev, &dev_attr_out0_output);
 215         device_create_file(&new_client->dev, &dev_attr_in0_input);
 216         device_create_file(&new_client->dev, &dev_attr_in1_input);
 217
 218         /* Register input2 if not in "two differential inputs" mode */
 219         if (input_mode != 3 )
 220                 device_create_file(&new_client->dev, &dev_attr_in2_input);
 221
 222         /* Register input3 only in "four single ended inputs" mode */
 223         if (input_mode == 0)
 224                 device_create_file(&new_client->dev, &dev_attr_in3_input);
 225
 226         return 0;
 227
 228         /* OK, this is not exactly good programming practice, usually. But it is
 229            very code-efficient in this case. */
 230
 231 exit_kfree:
 232         kfree(data);
 233 exit:
 234         return err;
 235 }
 236
 237 static int pcf8591_detach_client(struct i2c_client *client)
 238 {
 239         int err;
 240
 241         if ((err = i2c_detach_client(client)))
 242                 return err;
 243
 244         kfree(i2c_get_clientdata(client));
 245         return 0;
 246 }
 247
 248 /* Called when we have found a new PCF8591. */
 249 static void pcf8591_init_client(struct i2c_client *client)
 250 {
 251         struct pcf8591_data *data = i2c_get_clientdata(client);
 252         data->control = PCF8591_INIT_CONTROL;
 253         data->aout = PCF8591_INIT_AOUT;
 254
 255         i2c_smbus_write_byte_data(client, data->control, data->aout);
 256
 257         /* The first byte transmitted contains the conversion code of the
 258            previous read cycle. FLUSH IT! */
 259         i2c_smbus_read_byte(client);
 260 }
 261
 262 static int pcf8591_read_channel(struct device *dev, int channel)
 263 {
 264         u8 value;
 265         struct i2c_client *client = to_i2c_client(dev);
 266         struct pcf8591_data *data = i2c_get_clientdata(client);
 267
 268         down(&data->update_lock);
 269
 270         if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
 271                 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
 272                               | channel;
 273                 i2c_smbus_write_byte(client, data->control);
 274
 275                 /* The first byte transmitted contains the conversion code of
 276                    the previous read cycle. FLUSH IT! */
 277                 i2c_smbus_read_byte(client);
 278         }
 279         value = i2c_smbus_read_byte(client);
 280
 281         up(&data->update_lock);
 282
 283         if ((channel == 2 && input_mode == 2) ||
 284             (channel != 3 && (input_mode == 1 || input_mode == 3)))
 285                 return (10 * REG_TO_SIGNED(value));
 286         else
 287                 return (10 * value);
 288 }
 289
 290 static int __init pcf8591_init(void)
 291 {
 292         if (input_mode < 0 || input_mode > 3) {
 293                 printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
 294                        input_mode);
 295                 input_mode = 0;
 296         }
 297         return i2c_add_driver(&pcf8591_driver);
 298 }
 299
 300 static void __exit pcf8591_exit(void)
 301 {
 302         i2c_del_driver(&pcf8591_driver);
 303 }
 304
 305 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
 306 MODULE_DESCRIPTION("PCF8591 driver");
 307 MODULE_LICENSE("GPL");
 308
 309 module_init(pcf8591_init);
 310 module_exit(pcf8591_exit);