Pileus Git - ~andy/linux/blob - 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 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));
  27
  28 #define W1_F3A_RETRIES                     3
  29 #define W1_F3A_FUNC_PIO_ACCESS_READ        0xF5
  30 #define W1_F3A_FUNC_PIO_ACCESS_WRITE       0x5A
  31 #define W1_F3A_SUCCESS_CONFIRM_BYTE        0xAA
  32
  33 static ssize_t w1_f3a_read_state(
  34         struct file *filp, struct kobject *kobj,
  35         struct bin_attribute *bin_attr,
  36         char *buf, loff_t off, size_t count)
  37 {
  38         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  39         dev_dbg(&sl->dev,
  40                 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
  41                 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
  42
  43         if (off != 0)
  44                 return 0;
  45         if (!buf)
  46                 return -EINVAL;
  47
  48         mutex_lock(&sl->master->bus_mutex);
  49         dev_dbg(&sl->dev, "mutex locked");
  50
  51         if (w1_reset_select_slave(sl)) {
  52                 mutex_unlock(&sl->master->bus_mutex);
  53                 return -EIO;
  54         }
  55
  56         w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
  57         *buf = w1_read_8(sl->master);
  58
  59         mutex_unlock(&sl->master->bus_mutex);
  60         dev_dbg(&sl->dev, "mutex unlocked");
  61
  62         /* check for correct complement */
  63         if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
  64                 return -EIO;
  65         else
  66                 return 1;
  67 }
  68
  69 static ssize_t w1_f3a_write_output(
  70         struct file *filp, struct kobject *kobj,
  71         struct bin_attribute *bin_attr,
  72         char *buf, loff_t off, size_t count)
  73 {
  74         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  75         u8 w1_buf[3];
  76         unsigned int retries = W1_F3A_RETRIES;
  77
  78         if (count != 1 || off != 0)
  79                 return -EFAULT;
  80
  81         dev_dbg(&sl->dev, "locking mutex for write_output");
  82         mutex_lock(&sl->master->bus_mutex);
  83         dev_dbg(&sl->dev, "mutex locked");
  84
  85         if (w1_reset_select_slave(sl))
  86                 goto error;
  87
  88         /* according to the DS2413 datasheet the most significant 6 bits
  89            should be set to "1"s, so do it now */
  90         *buf = *buf | 0xFC;
  91
  92         while (retries--) {
  93                 w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
  94                 w1_buf[1] = *buf;
  95                 w1_buf[2] = ~(*buf);
  96                 w1_write_block(sl->master, w1_buf, 3);
  97
  98                 if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
  99                         mutex_unlock(&sl->master->bus_mutex);
 100                         dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries);
 101                         return 1;
 102                 }
 103                 if (w1_reset_resume_command(sl->master))
 104                         goto error;
 105         }
 106
 107 error:
 108         mutex_unlock(&sl->master->bus_mutex);
 109         dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
 110         return -EIO;
 111 }
 112
 113 #define NB_SYSFS_BIN_FILES 2
 114 static struct bin_attribute w1_f3a_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
 115         {
 116                 .attr = {
 117                         .name = "state",
 118                         .mode = S_IRUGO,
 119                 },
 120                 .size = 1,
 121                 .read = w1_f3a_read_state,
 122         },
 123         {
 124                 .attr = {
 125                         .name = "output",
 126                         .mode = S_IRUGO | S_IWUSR | S_IWGRP,
 127                 },
 128                 .size = 1,
 129                 .write = w1_f3a_write_output,
 130         }
 131 };
 132
 133 static int w1_f3a_add_slave(struct w1_slave *sl)
 134 {
 135         int err = 0;
 136         int i;
 137
 138         for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
 139                 err = sysfs_create_bin_file(
 140                         &sl->dev.kobj,
 141                         &(w1_f3a_sysfs_bin_files[i]));
 142         if (err)
 143                 while (--i >= 0)
 144                         sysfs_remove_bin_file(&sl->dev.kobj,
 145                                 &(w1_f3a_sysfs_bin_files[i]));
 146         return err;
 147 }
 148
 149 static void w1_f3a_remove_slave(struct w1_slave *sl)
 150 {
 151         int i;
 152         for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
 153                 sysfs_remove_bin_file(&sl->dev.kobj,
 154                         &(w1_f3a_sysfs_bin_files[i]));
 155 }
 156
 157 static struct w1_family_ops w1_f3a_fops = {
 158         .add_slave      = w1_f3a_add_slave,
 159         .remove_slave   = w1_f3a_remove_slave,
 160 };
 161
 162 static struct w1_family w1_family_3a = {
 163         .fid = W1_FAMILY_DS2413,
 164         .fops = &w1_f3a_fops,
 165 };
 166
 167 static int __init w1_f3a_init(void)
 168 {
 169         return w1_register_family(&w1_family_3a);
 170 }
 171
 172 static void __exit w1_f3a_exit(void)
 173 {
 174         w1_unregister_family(&w1_family_3a);
 175 }
 176
 177 module_init(w1_f3a_init);
 178 module_exit(w1_f3a_exit);