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
 25static ssize_t w1_f12_read_state(
 26	struct file *filp, struct kobject *kobj,
 27	const 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	ssize_t rtnval = 1;
 33
 34	if (off != 0)
 35		return 0;
 36	if (!buf)
 37		return -EINVAL;
 38
 39	mutex_lock(&sl->master->bus_mutex);
 40
 41	if (w1_reset_select_slave(sl)) {
 42		mutex_unlock(&sl->master->bus_mutex);
 43		return -EIO;
 44	}
 45
 46	w1_write_block(sl->master, w1_buf, 3);
 47	w1_read_block(sl->master, w1_buf+3, 3);
 48	if (crc16(0, w1_buf, sizeof(w1_buf)) == 0xb001) /* good read? */
 49		*buf = ((w1_buf[3]>>5)&3)|0x30;
 50	else
 51		rtnval = -EIO;
 52
 53	mutex_unlock(&sl->master->bus_mutex);
 54
 55	return rtnval;
 56}
 57
 58static ssize_t w1_f12_write_output(
 59	struct file *filp, struct kobject *kobj,
 60	const struct bin_attribute *bin_attr,
 61	char *buf, loff_t off, size_t count)
 62{
 63	struct w1_slave *sl = kobj_to_w1_slave(kobj);
 64	u8 w1_buf[6] = {W1_F12_FUNC_WRITE_STATUS, 7, 0, 0, 0, 0};
 65	ssize_t rtnval = 1;
 66
 67	if (count != 1 || off != 0)
 68		return -EFAULT;
 69
 70	mutex_lock(&sl->master->bus_mutex);
 71
 72	if (w1_reset_select_slave(sl)) {
 73		mutex_unlock(&sl->master->bus_mutex);
 74		return -EIO;
 75	}
 76
 77	w1_buf[3] = (((*buf)&3)<<5)|0x1F;
 78	w1_write_block(sl->master, w1_buf, 4);
 79	w1_read_block(sl->master, w1_buf+4, 2);
 80	if (crc16(0, w1_buf, sizeof(w1_buf)) == 0xb001) /* good read? */
 81		w1_write_8(sl->master, 0xFF);
 82	else
 83		rtnval = -EIO;
 84
 85	mutex_unlock(&sl->master->bus_mutex);
 86	return rtnval;
 87}
 88
 89#define NB_SYSFS_BIN_FILES 2
 90static const struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
 91	{
 92		.attr = {
 93			.name = "state",
 94			.mode = 0444,
 95		},
 96		.size = 1,
 97		.read = w1_f12_read_state,
 98	},
 99	{
100		.attr = {
101			.name = "output",
102			.mode = 0664,
103		},
104		.size = 1,
105		.write = w1_f12_write_output,
106	}
107};
108
109static int w1_f12_add_slave(struct w1_slave *sl)
110{
111	int err = 0;
112	int i;
113
114	for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
115		err = sysfs_create_bin_file(
116			&sl->dev.kobj,
117			&(w1_f12_sysfs_bin_files[i]));
118	if (err)
119		while (--i >= 0)
120			sysfs_remove_bin_file(&sl->dev.kobj,
121				&(w1_f12_sysfs_bin_files[i]));
122	return err;
123}
124
125static void w1_f12_remove_slave(struct w1_slave *sl)
126{
127	int i;
128
129	for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
130		sysfs_remove_bin_file(&sl->dev.kobj,
131			&(w1_f12_sysfs_bin_files[i]));
132}
133
134static const struct w1_family_ops w1_f12_fops = {
135	.add_slave      = w1_f12_add_slave,
136	.remove_slave   = w1_f12_remove_slave,
137};
138
139static struct w1_family w1_family_12 = {
140	.fid = W1_FAMILY_DS2406,
141	.fops = &w1_f12_fops,
142};
143module_w1_family(w1_family_12);
144
145MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
146MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
147MODULE_LICENSE("GPL");