drivers/w1/slaves/w1_ds2413.c

   1 /*
   2  * w1_ds2413.c - w1 family 3a (DS2413) driver
   3  * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
   4  *
   5  * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
   6  *
   7  * This source code is licensed under the GNU General Public License,
   8  * Version 2. See the file COPYING for more details.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/moduleparam.h>
  14 #include <linux/device.h>
  15 #include <linux/types.h>
  16 #include <linux/delay.h>
  17 #include <linux/slab.h>
  18
  19 #include "../w1.h"
  20 #include "../w1_int.h"
  21 #include "../w1_family.h"
  22
  23 MODULE_LICENSE("GPL");
  24 MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
  25 MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
  26
  27 #define W1_F3A_RETRIES                     3
  28 #define W1_F3A_FUNC_PIO_ACCESS_READ        0xF5
  29 #define W1_F3A_FUNC_PIO_ACCESS_WRITE       0x5A
  30 #define W1_F3A_SUCCESS_CONFIRM_BYTE        0xAA
  31
  32 static ssize_t w1_f3a_read_state(
  33         struct file *filp, struct kobject *kobj,
  34         struct bin_attribute *bin_attr,
  35         char *buf, loff_t off, size_t count)
  36 {
  37         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  38         dev_dbg(&sl->dev,
  39                 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
  40                 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
  41
  42         if (off != 0)
  43                 return 0;
  44         if (!buf)
  45                 return -EINVAL;
  46
  47         mutex_lock(&sl->master->bus_mutex);
  48         dev_dbg(&sl->dev, "mutex locked");
  49
  50         if (w1_reset_select_slave(sl)) {
  51                 mutex_unlock(&sl->master->bus_mutex);
  52                 return -EIO;
  53         }
  54
  55         w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
  56         *buf = w1_read_8(sl->master);
  57
  58         mutex_unlock(&sl->master->bus_mutex);
  59         dev_dbg(&sl->dev, "mutex unlocked");
  60
  61         /* check for correct complement */
  62         if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
  63                 return -EIO;
  64         else
  65                 return 1;
  66 }
  67
  68 static ssize_t w1_f3a_write_output(
  69         struct file *filp, struct kobject *kobj,
  70         struct bin_attribute *bin_attr,
  71         char *buf, loff_t off, size_t count)
  72 {
  73         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  74         u8 w1_buf[3];
  75         unsigned int retries = W1_F3A_RETRIES;
  76
  77         if (count != 1 || off != 0)
  78                 return -EFAULT;
  79
  80         dev_dbg(&sl->dev, "locking mutex for write_output");
  81         mutex_lock(&sl->master->bus_mutex);
  82         dev_dbg(&sl->dev, "mutex locked");
  83
  84         if (w1_reset_select_slave(sl))
  85                 goto error;
  86
  87         /* according to the DS2413 datasheet the most significant 6 bits
  88            should be set to "1"s, so do it now */
  89         *buf = *buf | 0xFC;
  90
  91         while (retries--) {
  92                 w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
  93                 w1_buf[1] = *buf;
  94                 w1_buf[2] = ~(*buf);
  95                 w1_write_block(sl->master, w1_buf, 3);
  96
  97                 if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
  98                         mutex_unlock(&sl->master->bus_mutex);
  99                         dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries);
 100                         return 1;
 101                 }
 102                 if (w1_reset_resume_command(sl->master))
 103                         goto error;
 104         }
 105
 106 error:
 107         mutex_unlock(&sl->master->bus_mutex);
 108         dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
 109         return -EIO;
 110 }
 111
 112 #define NB_SYSFS_BIN_FILES 2
 113 static struct bin_attribute w1_f3a_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
 114         {
 115                 .attr = {
 116                         .name = "state",
 117                         .mode = S_IRUGO,
 118                 },
 119                 .size = 1,
 120                 .read = w1_f3a_read_state,
 121         },
 122         {
 123                 .attr = {
 124                         .name = "output",
 125                         .mode = S_IRUGO | S_IWUSR | S_IWGRP,
 126                 },
 127                 .size = 1,
 128                 .write = w1_f3a_write_output,
 129         }
 130 };
 131
 132 static int w1_f3a_add_slave(struct w1_slave *sl)
 133 {
 134         int err = 0;
 135         int i;
 136
 137         for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
 138                 err = sysfs_create_bin_file(
 139                         &sl->dev.kobj,
 140                         &(w1_f3a_sysfs_bin_files[i]));
 141         if (err)
 142                 while (--i >= 0)
 143                         sysfs_remove_bin_file(&sl->dev.kobj,
 144                                 &(w1_f3a_sysfs_bin_files[i]));
 145         return err;
 146 }
 147
 148 static void w1_f3a_remove_slave(struct w1_slave *sl)
 149 {
 150         int i;
 151         for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
 152                 sysfs_remove_bin_file(&sl->dev.kobj,
 153                         &(w1_f3a_sysfs_bin_files[i]));
 154 }
 155
 156 static struct w1_family_ops w1_f3a_fops = {
 157         .add_slave      = w1_f3a_add_slave,
 158         .remove_slave   = w1_f3a_remove_slave,
 159 };
 160
 161 static struct w1_family w1_family_3a = {
 162         .fid = W1_FAMILY_DS2413,
 163         .fops = &w1_f3a_fops,
 164 };
 165
 166 static int __init w1_f3a_init(void)
 167 {
 168         return w1_register_family(&w1_family_3a);
 169 }
 170
 171 static void __exit w1_f3a_exit(void)
 172 {
 173         w1_unregister_family(&w1_family_3a);
 174 }
 175
 176 module_init(w1_f3a_init);
 177 module_exit(w1_f3a_exit);