drivers/w1/slaves/w1_ds2408.c

   1 /*
   2  *      w1_ds2408.c - w1 family 29 (DS2408) driver
   3  *
   4  * Copyright (c) 2010 Jean-Francois Dagenais <dagenaisj@sonatest.com>
   5  *
   6  * This source code is licensed under the GNU General Public License,
   7  * Version 2. See the file COPYING for more details.
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/moduleparam.h>
  13 #include <linux/device.h>
  14 #include <linux/types.h>
  15 #include <linux/delay.h>
  16 #include <linux/slab.h>
  17
  18 #include "../w1.h"
  19 #include "../w1_int.h"
  20 #include "../w1_family.h"
  21
  22 MODULE_LICENSE("GPL");
  23 MODULE_AUTHOR("Jean-Francois Dagenais <dagenaisj@sonatest.com>");
  24 MODULE_DESCRIPTION("w1 family 29 driver for DS2408 8 Pin IO");
  25
  26
  27 #define W1_F29_RETRIES          3
  28
  29 #define W1_F29_REG_LOGIG_STATE             0x88 /* R */
  30 #define W1_F29_REG_OUTPUT_LATCH_STATE      0x89 /* R */
  31 #define W1_F29_REG_ACTIVITY_LATCH_STATE    0x8A /* R */
  32 #define W1_F29_REG_COND_SEARCH_SELECT_MASK 0x8B /* RW */
  33 #define W1_F29_REG_COND_SEARCH_POL_SELECT  0x8C /* RW */
  34 #define W1_F29_REG_CONTROL_AND_STATUS      0x8D /* RW */
  35
  36 #define W1_F29_FUNC_READ_PIO_REGS          0xF0
  37 #define W1_F29_FUNC_CHANN_ACCESS_READ      0xF5
  38 #define W1_F29_FUNC_CHANN_ACCESS_WRITE     0x5A
  39 /* also used to write the control/status reg (0x8D): */
  40 #define W1_F29_FUNC_WRITE_COND_SEARCH_REG  0xCC
  41 #define W1_F29_FUNC_RESET_ACTIVITY_LATCHES 0xC3
  42
  43 #define W1_F29_SUCCESS_CONFIRM_BYTE        0xAA
  44
  45 static int _read_reg(struct w1_slave *sl, u8 address, unsigned char* buf)
  46 {
  47         u8 wrbuf[3];
  48         dev_dbg(&sl->dev,
  49                         "Reading with slave: %p, reg addr: %0#4x, buff addr: %p",
  50                         sl, (unsigned int)address, buf);
  51
  52         if (!buf)
  53                 return -EINVAL;
  54
  55         mutex_lock(&sl->master->mutex);
  56         dev_dbg(&sl->dev, "mutex locked");
  57
  58         if (w1_reset_select_slave(sl)) {
  59                 mutex_unlock(&sl->master->mutex);
  60                 return -EIO;
  61         }
  62
  63         wrbuf[0] = W1_F29_FUNC_READ_PIO_REGS;
  64         wrbuf[1] = address;
  65         wrbuf[2] = 0;
  66         w1_write_block(sl->master, wrbuf, 3);
  67         *buf = w1_read_8(sl->master);
  68
  69         mutex_unlock(&sl->master->mutex);
  70         dev_dbg(&sl->dev, "mutex unlocked");
  71         return 1;
  72 }
  73
  74 static ssize_t w1_f29_read_state(
  75         struct file *filp, struct kobject *kobj,
  76         struct bin_attribute *bin_attr,
  77         char *buf, loff_t off, size_t count)
  78 {
  79         dev_dbg(&kobj_to_w1_slave(kobj)->dev,
  80                 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
  81                 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
  82         if (count != 1 || off != 0)
  83                 return -EFAULT;
  84         return _read_reg(kobj_to_w1_slave(kobj), W1_F29_REG_LOGIG_STATE, buf);
  85 }
  86
  87 static ssize_t w1_f29_read_output(
  88         struct file *filp, struct kobject *kobj,
  89         struct bin_attribute *bin_attr,
  90         char *buf, loff_t off, size_t count)
  91 {
  92         dev_dbg(&kobj_to_w1_slave(kobj)->dev,
  93                 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
  94                 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
  95         if (count != 1 || off != 0)
  96                 return -EFAULT;
  97         return _read_reg(kobj_to_w1_slave(kobj),
  98                                          W1_F29_REG_OUTPUT_LATCH_STATE, buf);
  99 }
 100
 101 static ssize_t w1_f29_read_activity(
 102         struct file *filp, struct kobject *kobj,
 103         struct bin_attribute *bin_attr,
 104         char *buf, loff_t off, size_t count)
 105 {
 106         dev_dbg(&kobj_to_w1_slave(kobj)->dev,
 107                 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
 108                 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
 109         if (count != 1 || off != 0)
 110                 return -EFAULT;
 111         return _read_reg(kobj_to_w1_slave(kobj),
 112                                          W1_F29_REG_ACTIVITY_LATCH_STATE, buf);
 113 }
 114
 115 static ssize_t w1_f29_read_cond_search_mask(
 116         struct file *filp, struct kobject *kobj,
 117         struct bin_attribute *bin_attr,
 118         char *buf, loff_t off, size_t count)
 119 {
 120         dev_dbg(&kobj_to_w1_slave(kobj)->dev,
 121                 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
 122                 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
 123         if (count != 1 || off != 0)
 124                 return -EFAULT;
 125         return _read_reg(kobj_to_w1_slave(kobj),
 126                 W1_F29_REG_COND_SEARCH_SELECT_MASK, buf);
 127 }
 128
 129 static ssize_t w1_f29_read_cond_search_polarity(
 130         struct file *filp, struct kobject *kobj,
 131         struct bin_attribute *bin_attr,
 132         char *buf, loff_t off, size_t count)
 133 {
 134         if (count != 1 || off != 0)
 135                 return -EFAULT;
 136         return _read_reg(kobj_to_w1_slave(kobj),
 137                 W1_F29_REG_COND_SEARCH_POL_SELECT, buf);
 138 }
 139
 140 static ssize_t w1_f29_read_status_control(
 141         struct file *filp, struct kobject *kobj,
 142         struct bin_attribute *bin_attr,
 143         char *buf, loff_t off, size_t count)
 144 {
 145         if (count != 1 || off != 0)
 146                 return -EFAULT;
 147         return _read_reg(kobj_to_w1_slave(kobj),
 148                 W1_F29_REG_CONTROL_AND_STATUS, buf);
 149 }
 150
 151
 152
 153
 154 static ssize_t w1_f29_write_output(
 155         struct file *filp, struct kobject *kobj,
 156         struct bin_attribute *bin_attr,
 157         char *buf, loff_t off, size_t count)
 158 {
 159         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 160         u8 w1_buf[3];
 161         u8 readBack;
 162         unsigned int retries = W1_F29_RETRIES;
 163
 164         if (count != 1 || off != 0)
 165                 return -EFAULT;
 166
 167         dev_dbg(&sl->dev, "locking mutex for write_output");
 168         mutex_lock(&sl->master->mutex);
 169         dev_dbg(&sl->dev, "mutex locked");
 170
 171         if (w1_reset_select_slave(sl))
 172                 goto error;
 173
 174         while (retries--) {
 175                 w1_buf[0] = W1_F29_FUNC_CHANN_ACCESS_WRITE;
 176                 w1_buf[1] = *buf;
 177                 w1_buf[2] = ~(*buf);
 178                 w1_write_block(sl->master, w1_buf, 3);
 179
 180                 readBack = w1_read_8(sl->master);
 181                 /* here the master could read another byte which
 182                    would be the PIO reg (the actual pin logic state)
 183                    since in this driver we don't know which pins are
 184                    in and outs, there's no value to read the state and
 185                    compare. with (*buf) so end this command abruptly: */
 186                 if (w1_reset_resume_command(sl->master))
 187                         goto error;
 188
 189                 if (readBack != 0xAA) {
 190                         /* try again, the slave is ready for a command */
 191                         continue;
 192                 }
 193
 194                 /* go read back the output latches */
 195                 /* (the direct effect of the write above) */
 196                 w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
 197                 w1_buf[1] = W1_F29_REG_OUTPUT_LATCH_STATE;
 198                 w1_buf[2] = 0;
 199                 w1_write_block(sl->master, w1_buf, 3);
 200                 /* read the result of the READ_PIO_REGS command */
 201                 if (w1_read_8(sl->master) == *buf) {
 202                         /* success! */
 203                         mutex_unlock(&sl->master->mutex);
 204                         dev_dbg(&sl->dev,
 205                                 "mutex unlocked, retries:%d", retries);
 206                         return 1;
 207                 }
 208         }
 209 error:
 210         mutex_unlock(&sl->master->mutex);
 211         dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
 212
 213         return -EIO;
 214 }
 215
 216
 217 /**
 218  * Writing to the activity file resets the activity latches.
 219  */
 220 static ssize_t w1_f29_write_activity(
 221         struct file *filp, struct kobject *kobj,
 222         struct bin_attribute *bin_attr,
 223         char *buf, loff_t off, size_t count)
 224 {
 225         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 226         unsigned int retries = W1_F29_RETRIES;
 227
 228         if (count != 1 || off != 0)
 229                 return -EFAULT;
 230
 231         mutex_lock(&sl->master->mutex);
 232
 233         if (w1_reset_select_slave(sl))
 234                 goto error;
 235
 236         while (retries--) {
 237                 w1_write_8(sl->master, W1_F29_FUNC_RESET_ACTIVITY_LATCHES);
 238                 if (w1_read_8(sl->master) == W1_F29_SUCCESS_CONFIRM_BYTE) {
 239                         mutex_unlock(&sl->master->mutex);
 240                         return 1;
 241                 }
 242                 if (w1_reset_resume_command(sl->master))
 243                         goto error;
 244         }
 245
 246 error:
 247         mutex_unlock(&sl->master->mutex);
 248         return -EIO;
 249 }
 250
 251 static ssize_t w1_f29_write_status_control(
 252         struct file *filp,
 253         struct kobject *kobj,
 254         struct bin_attribute *bin_attr,
 255         char *buf,
 256         loff_t off,
 257         size_t count)
 258 {
 259         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 260         u8 w1_buf[4];
 261         unsigned int retries = W1_F29_RETRIES;
 262
 263         if (count != 1 || off != 0)
 264                 return -EFAULT;
 265
 266         mutex_lock(&sl->master->mutex);
 267
 268         if (w1_reset_select_slave(sl))
 269                 goto error;
 270
 271         while (retries--) {
 272                 w1_buf[0] = W1_F29_FUNC_WRITE_COND_SEARCH_REG;
 273                 w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS;
 274                 w1_buf[2] = 0;
 275                 w1_buf[3] = *buf;
 276
 277                 w1_write_block(sl->master, w1_buf, 4);
 278                 if (w1_reset_resume_command(sl->master))
 279                         goto error;
 280
 281                 w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
 282                 w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS;
 283                 w1_buf[2] = 0;
 284
 285                 w1_write_block(sl->master, w1_buf, 3);
 286                 if (w1_read_8(sl->master) == *buf) {
 287                         /* success! */
 288                         mutex_unlock(&sl->master->mutex);
 289                         return 1;
 290                 }
 291         }
 292 error:
 293         mutex_unlock(&sl->master->mutex);
 294
 295         return -EIO;
 296 }
 297
 298
 299
 300 #define NB_SYSFS_BIN_FILES 6
 301 static struct bin_attribute w1_f29_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
 302         {
 303                 .attr = {
 304                         .name = "state",
 305                         .mode = S_IRUGO,
 306                 },
 307                 .size = 1,
 308                 .read = w1_f29_read_state,
 309         },
 310         {
 311                 .attr = {
 312                         .name = "output",
 313                         .mode = S_IRUGO | S_IWUSR | S_IWGRP,
 314                 },
 315                 .size = 1,
 316                 .read = w1_f29_read_output,
 317                 .write = w1_f29_write_output,
 318         },
 319         {
 320                 .attr = {
 321                         .name = "activity",
 322                         .mode = S_IRUGO,
 323                 },
 324                 .size = 1,
 325                 .read = w1_f29_read_activity,
 326                 .write = w1_f29_write_activity,
 327         },
 328         {
 329                 .attr = {
 330                         .name = "cond_search_mask",
 331                         .mode = S_IRUGO,
 332                 },
 333                 .size = 1,
 334                 .read = w1_f29_read_cond_search_mask,
 335                 .write = 0,
 336         },
 337         {
 338                 .attr = {
 339                         .name = "cond_search_polarity",
 340                         .mode = S_IRUGO,
 341                 },
 342                 .size = 1,
 343                 .read = w1_f29_read_cond_search_polarity,
 344                 .write = 0,
 345         },
 346         {
 347                 .attr = {
 348                         .name = "status_control",
 349                         .mode = S_IRUGO | S_IWUSR | S_IWGRP,
 350                 },
 351                 .size = 1,
 352                 .read = w1_f29_read_status_control,
 353                 .write = w1_f29_write_status_control,
 354         }
 355 };
 356
 357 static int w1_f29_add_slave(struct w1_slave *sl)
 358 {
 359         int err = 0;
 360         int i;
 361
 362         for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
 363                 err = sysfs_create_bin_file(
 364                         &sl->dev.kobj,
 365                         &(w1_f29_sysfs_bin_files[i]));
 366         if (err)
 367                 while (--i >= 0)
 368                         sysfs_remove_bin_file(&sl->dev.kobj,
 369                                 &(w1_f29_sysfs_bin_files[i]));
 370         return err;
 371 }
 372
 373 static void w1_f29_remove_slave(struct w1_slave *sl)
 374 {
 375         int i;
 376         for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
 377                 sysfs_remove_bin_file(&sl->dev.kobj,
 378                         &(w1_f29_sysfs_bin_files[i]));
 379 }
 380
 381 static struct w1_family_ops w1_f29_fops = {
 382         .add_slave      = w1_f29_add_slave,
 383         .remove_slave   = w1_f29_remove_slave,
 384 };
 385
 386 static struct w1_family w1_family_29 = {
 387         .fid = W1_FAMILY_DS2408,
 388         .fops = &w1_f29_fops,
 389 };
 390
 391 static int __init w1_f29_init(void)
 392 {
 393         return w1_register_family(&w1_family_29);
 394 }
 395
 396 static void __exit w1_f29_exit(void)
 397 {
 398         w1_unregister_family(&w1_family_29);
 399 }
 400
 401 module_init(w1_f29_init);
 402 module_exit(w1_f29_exit);