drivers/w1/slaves/w1_ds2413.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * w1_ds2413.c - w1 family 3a (DS2413) driver
   4  * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
   5  *
   6  * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
   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
  17 #include <linux/w1.h>
  18
  19 #define W1_FAMILY_DS2413        0x3A
  20
  21 #define W1_F3A_RETRIES                     3
  22 #define W1_F3A_FUNC_PIO_ACCESS_READ        0xF5
  23 #define W1_F3A_FUNC_PIO_ACCESS_WRITE       0x5A
  24 #define W1_F3A_SUCCESS_CONFIRM_BYTE        0xAA
  25
  26 static ssize_t state_read(struct file *filp, struct kobject *kobj,
  27                           struct bin_attribute *bin_attr, char *buf, loff_t off,
  28                           size_t count)
  29 {
  30         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  31         dev_dbg(&sl->dev,
  32                 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
  33                 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
  34
  35         if (off != 0)
  36                 return 0;
  37         if (!buf)
  38                 return -EINVAL;
  39
  40         mutex_lock(&sl->master->bus_mutex);
  41         dev_dbg(&sl->dev, "mutex locked");
  42
  43         if (w1_reset_select_slave(sl)) {
  44                 mutex_unlock(&sl->master->bus_mutex);
  45                 return -EIO;
  46         }
  47
  48         w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
  49         *buf = w1_read_8(sl->master);
  50
  51         mutex_unlock(&sl->master->bus_mutex);
  52         dev_dbg(&sl->dev, "mutex unlocked");
  53
  54         /* check for correct complement */
  55         if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
  56                 return -EIO;
  57         else
  58                 return 1;
  59 }
  60
  61 static BIN_ATTR_RO(state, 1);
  62
  63 static ssize_t output_write(struct file *filp, struct kobject *kobj,
  64                             struct bin_attribute *bin_attr, char *buf,
  65                             loff_t off, size_t count)
  66 {
  67         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  68         u8 w1_buf[3];
  69         unsigned int retries = W1_F3A_RETRIES;
  70
  71         if (count != 1 || off != 0)
  72                 return -EFAULT;
  73
  74         dev_dbg(&sl->dev, "locking mutex for write_output");
  75         mutex_lock(&sl->master->bus_mutex);
  76         dev_dbg(&sl->dev, "mutex locked");
  77
  78         if (w1_reset_select_slave(sl))
  79                 goto error;
  80
  81         /* according to the DS2413 datasheet the most significant 6 bits
  82            should be set to "1"s, so do it now */
  83         *buf = *buf | 0xFC;
  84
  85         while (retries--) {
  86                 w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
  87                 w1_buf[1] = *buf;
  88                 w1_buf[2] = ~(*buf);
  89                 w1_write_block(sl->master, w1_buf, 3);
  90
  91                 if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
  92                         mutex_unlock(&sl->master->bus_mutex);
  93                         dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries);
  94                         return 1;
  95                 }
  96                 if (w1_reset_resume_command(sl->master))
  97                         goto error;
  98         }
  99
 100 error:
 101         mutex_unlock(&sl->master->bus_mutex);
 102         dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
 103         return -EIO;
 104 }
 105
 106 static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
 107
 108 static struct bin_attribute *w1_f3a_bin_attrs[] = {
 109         &bin_attr_state,
 110         &bin_attr_output,
 111         NULL,
 112 };
 113
 114 static const struct attribute_group w1_f3a_group = {
 115         .bin_attrs = w1_f3a_bin_attrs,
 116 };
 117
 118 static const struct attribute_group *w1_f3a_groups[] = {
 119         &w1_f3a_group,
 120         NULL,
 121 };
 122
 123 static struct w1_family_ops w1_f3a_fops = {
 124         .groups         = w1_f3a_groups,
 125 };
 126
 127 static struct w1_family w1_family_3a = {
 128         .fid = W1_FAMILY_DS2413,
 129         .fops = &w1_f3a_fops,
 130 };
 131 module_w1_family(w1_family_3a);
 132
 133 MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
 134 MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
 135 MODULE_LICENSE("GPL");
 136 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));