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 <linux/w1.h>
  21
  22 #define W1_FAMILY_DS2406        0x12
  23
  24 #define W1_F12_FUNC_READ_STATUS            0xAA
  25 #define W1_F12_FUNC_WRITE_STATUS           0x55
  26
  27 static ssize_t w1_f12_read_state(
  28         struct file *filp, struct kobject *kobj,
  29         struct bin_attribute *bin_attr,
  30         char *buf, loff_t off, size_t count)
  31 {
  32         u8 w1_buf[6]={W1_F12_FUNC_READ_STATUS, 7, 0, 0, 0, 0};
  33         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  34         u16 crc=0;
  35         int i;
  36         ssize_t rtnval=1;
  37
  38         if (off != 0)
  39                 return 0;
  40         if (!buf)
  41                 return -EINVAL;
  42
  43         mutex_lock(&sl->master->bus_mutex);
  44
  45         if (w1_reset_select_slave(sl)) {
  46                 mutex_unlock(&sl->master->bus_mutex);
  47                 return -EIO;
  48         }
  49
  50         w1_write_block(sl->master, w1_buf, 3);
  51         w1_read_block(sl->master, w1_buf+3, 3);
  52         for (i=0; i<6; i++)
  53                 crc=crc16_byte(crc, w1_buf[i]);
  54         if (crc==0xb001) /* good read? */
  55                 *buf=((w1_buf[3]>>5)&3)|0x30;
  56         else
  57                 rtnval=-EIO;
  58
  59         mutex_unlock(&sl->master->bus_mutex);
  60
  61         return rtnval;
  62 }
  63
  64 static ssize_t w1_f12_write_output(
  65         struct file *filp, struct kobject *kobj,
  66         struct bin_attribute *bin_attr,
  67         char *buf, loff_t off, size_t count)
  68 {
  69         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  70         u8 w1_buf[6]={W1_F12_FUNC_WRITE_STATUS, 7, 0, 0, 0, 0};
  71         u16 crc=0;
  72         int i;
  73         ssize_t rtnval=1;
  74
  75         if (count != 1 || off != 0)
  76                 return -EFAULT;
  77
  78         mutex_lock(&sl->master->bus_mutex);
  79
  80         if (w1_reset_select_slave(sl)) {
  81                 mutex_unlock(&sl->master->bus_mutex);
  82                 return -EIO;
  83         }
  84
  85         w1_buf[3] = (((*buf)&3)<<5)|0x1F;
  86         w1_write_block(sl->master, w1_buf, 4);
  87         w1_read_block(sl->master, w1_buf+4, 2);
  88         for (i=0; i<6; i++)
  89                 crc=crc16_byte(crc, w1_buf[i]);
  90         if (crc==0xb001) /* good read? */
  91                 w1_write_8(sl->master, 0xFF);
  92         else
  93                 rtnval=-EIO;
  94
  95         mutex_unlock(&sl->master->bus_mutex);
  96         return rtnval;
  97 }
  98
  99 #define NB_SYSFS_BIN_FILES 2
 100 static struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
 101         {
 102                 .attr = {
 103                         .name = "state",
 104                         .mode = S_IRUGO,
 105                 },
 106                 .size = 1,
 107                 .read = w1_f12_read_state,
 108         },
 109         {
 110                 .attr = {
 111                         .name = "output",
 112                         .mode = S_IRUGO | S_IWUSR | S_IWGRP,
 113                 },
 114                 .size = 1,
 115                 .write = w1_f12_write_output,
 116         }
 117 };
 118
 119 static int w1_f12_add_slave(struct w1_slave *sl)
 120 {
 121         int err = 0;
 122         int i;
 123
 124         for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
 125                 err = sysfs_create_bin_file(
 126                         &sl->dev.kobj,
 127                         &(w1_f12_sysfs_bin_files[i]));
 128         if (err)
 129                 while (--i >= 0)
 130                         sysfs_remove_bin_file(&sl->dev.kobj,
 131                                 &(w1_f12_sysfs_bin_files[i]));
 132         return err;
 133 }
 134
 135 static void w1_f12_remove_slave(struct w1_slave *sl)
 136 {
 137         int i;
 138         for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
 139                 sysfs_remove_bin_file(&sl->dev.kobj,
 140                         &(w1_f12_sysfs_bin_files[i]));
 141 }
 142
 143 static struct w1_family_ops w1_f12_fops = {
 144         .add_slave      = w1_f12_add_slave,
 145         .remove_slave   = w1_f12_remove_slave,
 146 };
 147
 148 static struct w1_family w1_family_12 = {
 149         .fid = W1_FAMILY_DS2406,
 150         .fops = &w1_f12_fops,
 151 };
 152 module_w1_family(w1_family_12);
 153
 154 MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
 155 MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
 156 MODULE_LICENSE("GPL");