drivers/w1/slaves/w1_ds2406.c

   1 /*
   2  * w1_ds2406.c - w1 family 12 (DS2406) driver
   3  * based on w1_ds2413.c by Mariusz Bialonczyk <manio@skyboo.net>
   4  *
   5  * Copyright (c) 2014 Scott Alfter <scott@alfter.us>
   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 #include <linux/crc16.h>
  19
  20 #include "../w1.h"
  21 #include "../w1_int.h"
  22 #include "../w1_family.h"
  23
  24 MODULE_LICENSE("GPL");
  25 MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
  26 MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
  27
  28 #define W1_F12_FUNC_READ_STATUS            0xAA
  29 #define W1_F12_FUNC_WRITE_STATUS           0x55
  30
  31 static ssize_t w1_f12_read_state(
  32         struct file *filp, struct kobject *kobj,
  33         struct bin_attribute *bin_attr,
  34         char *buf, loff_t off, size_t count)
  35 {
  36         u8 w1_buf[6]={W1_F12_FUNC_READ_STATUS, 7, 0, 0, 0, 0};
  37         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  38         u16 crc=0;
  39         int i;
  40         ssize_t rtnval=1;
  41
  42         if (off != 0)
  43                 return 0;
  44         if (!buf)
  45                 return -EINVAL;
  46
  47         mutex_lock(&sl->master->bus_mutex);
  48
  49         if (w1_reset_select_slave(sl)) {
  50                 mutex_unlock(&sl->master->bus_mutex);
  51                 return -EIO;
  52         }
  53
  54         w1_write_block(sl->master, w1_buf, 3);
  55         w1_read_block(sl->master, w1_buf+3, 3);
  56         for (i=0; i<6; i++)
  57                 crc=crc16_byte(crc, w1_buf[i]);
  58         if (crc==0xb001) /* good read? */
  59                 *buf=((w1_buf[3]>>5)&3)|0x30;
  60         else
  61                 rtnval=-EIO;
  62
  63         mutex_unlock(&sl->master->bus_mutex);
  64
  65         return rtnval;
  66 }
  67
  68 static ssize_t w1_f12_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[6]={W1_F12_FUNC_WRITE_STATUS, 7, 0, 0, 0, 0};
  75         u16 crc=0;
  76         int i;
  77         ssize_t rtnval=1;
  78
  79         if (count != 1 || off != 0)
  80                 return -EFAULT;
  81
  82         mutex_lock(&sl->master->bus_mutex);
  83
  84         if (w1_reset_select_slave(sl)) {
  85                 mutex_unlock(&sl->master->bus_mutex);
  86                 return -EIO;
  87         }
  88
  89         w1_buf[3] = (((*buf)&3)<<5)|0x1F;
  90         w1_write_block(sl->master, w1_buf, 4);
  91         w1_read_block(sl->master, w1_buf+4, 2);
  92         for (i=0; i<6; i++)
  93                 crc=crc16_byte(crc, w1_buf[i]);
  94         if (crc==0xb001) /* good read? */
  95                 w1_write_8(sl->master, 0xFF);
  96         else
  97                 rtnval=-EIO;
  98
  99         mutex_unlock(&sl->master->bus_mutex);
 100         return rtnval;
 101 }
 102
 103 #define NB_SYSFS_BIN_FILES 2
 104 static struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
 105         {
 106                 .attr = {
 107                         .name = "state",
 108                         .mode = S_IRUGO,
 109                 },
 110                 .size = 1,
 111                 .read = w1_f12_read_state,
 112         },
 113         {
 114                 .attr = {
 115                         .name = "output",
 116                         .mode = S_IRUGO | S_IWUSR | S_IWGRP,
 117                 },
 118                 .size = 1,
 119                 .write = w1_f12_write_output,
 120         }
 121 };
 122
 123 static int w1_f12_add_slave(struct w1_slave *sl)
 124 {
 125         int err = 0;
 126         int i;
 127
 128         for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
 129                 err = sysfs_create_bin_file(
 130                         &sl->dev.kobj,
 131                         &(w1_f12_sysfs_bin_files[i]));
 132         if (err)
 133                 while (--i >= 0)
 134                         sysfs_remove_bin_file(&sl->dev.kobj,
 135                                 &(w1_f12_sysfs_bin_files[i]));
 136         return err;
 137 }
 138
 139 static void w1_f12_remove_slave(struct w1_slave *sl)
 140 {
 141         int i;
 142         for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
 143                 sysfs_remove_bin_file(&sl->dev.kobj,
 144                         &(w1_f12_sysfs_bin_files[i]));
 145 }
 146
 147 static struct w1_family_ops w1_f12_fops = {
 148         .add_slave      = w1_f12_add_slave,
 149         .remove_slave   = w1_f12_remove_slave,
 150 };
 151
 152 static struct w1_family w1_family_12 = {
 153         .fid = W1_FAMILY_DS2406,
 154         .fops = &w1_f12_fops,
 155 };
 156
 157 static int __init w1_f12_init(void)
 158 {
 159         return w1_register_family(&w1_family_12);
 160 }
 161
 162 static void __exit w1_f12_exit(void)
 163 {
 164         w1_unregister_family(&w1_family_12);
 165 }
 166
 167 module_init(w1_f12_init);
 168 module_exit(w1_f12_exit);