LXR linux/drivers/w1/slaves/w1

   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
  27static 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
  64static 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
 100static 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
 119static 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
 135static 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
 143static struct w1_family_ops w1_f12_fops = {
 144        .add_slave      = w1_f12_add_slave,
 145        .remove_slave   = w1_f12_remove_slave,
 146};
 147
 148static struct w1_family w1_family_12 = {
 149        .fid = W1_FAMILY_DS2406,
 150        .fops = &w1_f12_fops,
 151};
 152module_w1_family(w1_family_12);
 153
 154MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
 155MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
 156MODULE_LICENSE("GPL");
 157