drivers/w1/slaves/w1_ds2406.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * w1_ds2406.c - w1 family 12 (DS2406) driver
   4  * based on w1_ds2413.c by Mariusz Bialonczyk <manio@skyboo.net>
   5  *
   6  * Copyright (c) 2014 Scott Alfter <scott@alfter.us>
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/moduleparam.h>
  12 #include <linux/device.h>
  13 #include <linux/types.h>
  14 #include <linux/delay.h>
  15 #include <linux/slab.h>
  16 #include <linux/crc16.h>
  17
  18 #include <linux/w1.h>
  19
  20 #define W1_FAMILY_DS2406        0x12
  21
  22 #define W1_F12_FUNC_READ_STATUS            0xAA
  23 #define W1_F12_FUNC_WRITE_STATUS           0x55
  24
  25 static ssize_t w1_f12_read_state(
  26         struct file *filp, struct kobject *kobj,
  27         struct bin_attribute *bin_attr,
  28         char *buf, loff_t off, size_t count)
  29 {
  30         u8 w1_buf[6]={W1_F12_FUNC_READ_STATUS, 7, 0, 0, 0, 0};
  31         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  32         u16 crc=0;
  33         int i;
  34         ssize_t rtnval=1;
  35
  36         if (off != 0)
  37                 return 0;
  38         if (!buf)
  39                 return -EINVAL;
  40
  41         mutex_lock(&sl->master->bus_mutex);
  42
  43         if (w1_reset_select_slave(sl)) {
  44                 mutex_unlock(&sl->master->bus_mutex);
  45                 return -EIO;
  46         }
  47
  48         w1_write_block(sl->master, w1_buf, 3);
  49         w1_read_block(sl->master, w1_buf+3, 3);
  50         for (i=0; i<6; i++)
  51                 crc=crc16_byte(crc, w1_buf[i]);
  52         if (crc==0xb001) /* good read? */
  53                 *buf=((w1_buf[3]>>5)&3)|0x30;
  54         else
  55                 rtnval=-EIO;
  56
  57         mutex_unlock(&sl->master->bus_mutex);
  58
  59         return rtnval;
  60 }
  61
  62 static ssize_t w1_f12_write_output(
  63         struct file *filp, struct kobject *kobj,
  64         struct bin_attribute *bin_attr,
  65         char *buf, loff_t off, size_t count)
  66 {
  67         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  68         u8 w1_buf[6]={W1_F12_FUNC_WRITE_STATUS, 7, 0, 0, 0, 0};
  69         u16 crc=0;
  70         int i;
  71         ssize_t rtnval=1;
  72
  73         if (count != 1 || off != 0)
  74                 return -EFAULT;
  75
  76         mutex_lock(&sl->master->bus_mutex);
  77
  78         if (w1_reset_select_slave(sl)) {
  79                 mutex_unlock(&sl->master->bus_mutex);
  80                 return -EIO;
  81         }
  82
  83         w1_buf[3] = (((*buf)&3)<<5)|0x1F;
  84         w1_write_block(sl->master, w1_buf, 4);
  85         w1_read_block(sl->master, w1_buf+4, 2);
  86         for (i=0; i<6; i++)
  87                 crc=crc16_byte(crc, w1_buf[i]);
  88         if (crc==0xb001) /* good read? */
  89                 w1_write_8(sl->master, 0xFF);
  90         else
  91                 rtnval=-EIO;
  92
  93         mutex_unlock(&sl->master->bus_mutex);
  94         return rtnval;
  95 }
  96
  97 #define NB_SYSFS_BIN_FILES 2
  98 static struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
  99         {
 100                 .attr = {
 101                         .name = "state",
 102                         .mode = S_IRUGO,
 103                 },
 104                 .size = 1,
 105                 .read = w1_f12_read_state,
 106         },
 107         {
 108                 .attr = {
 109                         .name = "output",
 110                         .mode = S_IRUGO | S_IWUSR | S_IWGRP,
 111                 },
 112                 .size = 1,
 113                 .write = w1_f12_write_output,
 114         }
 115 };
 116
 117 static int w1_f12_add_slave(struct w1_slave *sl)
 118 {
 119         int err = 0;
 120         int i;
 121
 122         for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
 123                 err = sysfs_create_bin_file(
 124                         &sl->dev.kobj,
 125                         &(w1_f12_sysfs_bin_files[i]));
 126         if (err)
 127                 while (--i >= 0)
 128                         sysfs_remove_bin_file(&sl->dev.kobj,
 129                                 &(w1_f12_sysfs_bin_files[i]));
 130         return err;
 131 }
 132
 133 static void w1_f12_remove_slave(struct w1_slave *sl)
 134 {
 135         int i;
 136         for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
 137                 sysfs_remove_bin_file(&sl->dev.kobj,
 138                         &(w1_f12_sysfs_bin_files[i]));
 139 }
 140
 141 static struct w1_family_ops w1_f12_fops = {
 142         .add_slave      = w1_f12_add_slave,
 143         .remove_slave   = w1_f12_remove_slave,
 144 };
 145
 146 static struct w1_family w1_family_12 = {
 147         .fid = W1_FAMILY_DS2406,
 148         .fops = &w1_f12_fops,
 149 };
 150 module_w1_family(w1_family_12);
 151
 152 MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
 153 MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
 154 MODULE_LICENSE("GPL");