LXR linux/drivers/w1/slaves/w1

   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#define W1_F3A_INVALID_PIO_STATE           0xFF
  26
  27static ssize_t state_read(struct file *filp, struct kobject *kobj,
  28                          struct bin_attribute *bin_attr, char *buf, loff_t off,
  29                          size_t count)
  30{
  31        struct w1_slave *sl = kobj_to_w1_slave(kobj);
  32        unsigned int retries = W1_F3A_RETRIES;
  33        ssize_t bytes_read = -EIO;
  34        u8 state;
  35
  36        dev_dbg(&sl->dev,
  37                "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
  38                bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
  39
  40        if (off != 0)
  41                return 0;
  42        if (!buf)
  43                return -EINVAL;
  44
  45        mutex_lock(&sl->master->bus_mutex);
  46        dev_dbg(&sl->dev, "mutex locked");
  47
  48next:
  49        if (w1_reset_select_slave(sl))
  50                goto out;
  51
  52        while (retries--) {
  53                w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
  54
  55                state = w1_read_8(sl->master);
  56                if ((state & 0x0F) == ((~state >> 4) & 0x0F)) {
  57                        /* complement is correct */
  58                        *buf = state;
  59                        bytes_read = 1;
  60                        goto out;
  61                } else if (state == W1_F3A_INVALID_PIO_STATE) {
  62                        /* slave didn't respond, try to select it again */
  63                        dev_warn(&sl->dev, "slave device did not respond to PIO_ACCESS_READ, " \
  64                                            "reselecting, retries left: %d\n", retries);
  65                        goto next;
  66                }
  67
  68                if (w1_reset_resume_command(sl->master))
  69                        goto out; /* unrecoverable error */
  70
  71                dev_warn(&sl->dev, "PIO_ACCESS_READ error, retries left: %d\n", retries);
  72        }
  73
  74out:
  75        mutex_unlock(&sl->master->bus_mutex);
  76        dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
  77                (bytes_read > 0) ? "succeeded" : "error", retries);
  78        return bytes_read;
  79}
  80
  81static BIN_ATTR_RO(state, 1);
  82
  83static ssize_t output_write(struct file *filp, struct kobject *kobj,
  84                            struct bin_attribute *bin_attr, char *buf,
  85                            loff_t off, size_t count)
  86{
  87        struct w1_slave *sl = kobj_to_w1_slave(kobj);
  88        u8 w1_buf[3];
  89        unsigned int retries = W1_F3A_RETRIES;
  90        ssize_t bytes_written = -EIO;
  91
  92        if (count != 1 || off != 0)
  93                return -EFAULT;
  94
  95        dev_dbg(&sl->dev, "locking mutex for write_output");
  96        mutex_lock(&sl->master->bus_mutex);
  97        dev_dbg(&sl->dev, "mutex locked");
  98
  99        if (w1_reset_select_slave(sl))
 100                goto out;
 101
 102        /* according to the DS2413 datasheet the most significant 6 bits
 103           should be set to "1"s, so do it now */
 104        *buf = *buf | 0xFC;
 105
 106        while (retries--) {
 107                w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
 108                w1_buf[1] = *buf;
 109                w1_buf[2] = ~(*buf);
 110                w1_write_block(sl->master, w1_buf, 3);
 111
 112                if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
 113                        bytes_written = 1;
 114                        goto out;
 115                }
 116                if (w1_reset_resume_command(sl->master))
 117                        goto out; /* unrecoverable error */
 118
 119                dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n", retries);
 120        }
 121
 122out:
 123        mutex_unlock(&sl->master->bus_mutex);
 124        dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
 125                (bytes_written > 0) ? "succeeded" : "error", retries);
 126        return bytes_written;
 127}
 128
 129static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
 130
 131static struct bin_attribute *w1_f3a_bin_attrs[] = {
 132        &bin_attr_state,
 133        &bin_attr_output,
 134        NULL,
 135};
 136
 137static const struct attribute_group w1_f3a_group = {
 138        .bin_attrs = w1_f3a_bin_attrs,
 139};
 140
 141static const struct attribute_group *w1_f3a_groups[] = {
 142        &w1_f3a_group,
 143        NULL,
 144};
 145
 146static struct w1_family_ops w1_f3a_fops = {
 147        .groups         = w1_f3a_groups,
 148};
 149
 150static struct w1_family w1_family_3a = {
 151        .fid = W1_FAMILY_DS2413,
 152        .fops = &w1_f3a_fops,
 153};
 154module_w1_family(w1_family_3a);
 155
 156MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
 157MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
 158MODULE_LICENSE("GPL");
 159MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));
 160