drivers/w1/slaves/w1_ds2406.c

Source file repositories/reference/linux-study-clean/drivers/w1/slaves/w1_ds2406.c

File Facts

System
Linux kernel
Corpus path
drivers/w1/slaves/w1_ds2406.c
Extension
.c
Size
3285 bytes
Lines
148
Domain
Driver Families
Bucket
drivers/w1
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 * w1_ds2406.c - w1 family 12 (DS2406) driver
 * based on w1_ds2413.c by Mariusz Bialonczyk <manio@skyboo.net>
 *
 * Copyright (c) 2014 Scott Alfter <scott@alfter.us>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/crc16.h>

#include <linux/w1.h>

#define W1_FAMILY_DS2406	0x12

#define W1_F12_FUNC_READ_STATUS		   0xAA
#define W1_F12_FUNC_WRITE_STATUS	   0x55

static ssize_t w1_f12_read_state(
	struct file *filp, struct kobject *kobj,
	const struct bin_attribute *bin_attr,
	char *buf, loff_t off, size_t count)
{
	u8 w1_buf[6] = {W1_F12_FUNC_READ_STATUS, 7, 0, 0, 0, 0};
	struct w1_slave *sl = kobj_to_w1_slave(kobj);
	ssize_t rtnval = 1;

	if (off != 0)
		return 0;
	if (!buf)
		return -EINVAL;

	mutex_lock(&sl->master->bus_mutex);

	if (w1_reset_select_slave(sl)) {
		mutex_unlock(&sl->master->bus_mutex);
		return -EIO;
	}

	w1_write_block(sl->master, w1_buf, 3);
	w1_read_block(sl->master, w1_buf+3, 3);
	if (crc16(0, w1_buf, sizeof(w1_buf)) == 0xb001) /* good read? */
		*buf = ((w1_buf[3]>>5)&3)|0x30;
	else
		rtnval = -EIO;

	mutex_unlock(&sl->master->bus_mutex);

	return rtnval;
}

static ssize_t w1_f12_write_output(
	struct file *filp, struct kobject *kobj,
	const struct bin_attribute *bin_attr,
	char *buf, loff_t off, size_t count)
{
	struct w1_slave *sl = kobj_to_w1_slave(kobj);
	u8 w1_buf[6] = {W1_F12_FUNC_WRITE_STATUS, 7, 0, 0, 0, 0};
	ssize_t rtnval = 1;

	if (count != 1 || off != 0)
		return -EFAULT;

	mutex_lock(&sl->master->bus_mutex);

	if (w1_reset_select_slave(sl)) {
		mutex_unlock(&sl->master->bus_mutex);
		return -EIO;
	}

	w1_buf[3] = (((*buf)&3)<<5)|0x1F;
	w1_write_block(sl->master, w1_buf, 4);
	w1_read_block(sl->master, w1_buf+4, 2);
	if (crc16(0, w1_buf, sizeof(w1_buf)) == 0xb001) /* good read? */
		w1_write_8(sl->master, 0xFF);
	else
		rtnval = -EIO;

	mutex_unlock(&sl->master->bus_mutex);
	return rtnval;
}

#define NB_SYSFS_BIN_FILES 2
static const struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {

Annotation

Implementation Notes