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#define W1_F3A_INVALID_PIO_STATE           0xFF
 26
 27static ssize_t state_read(struct file *filp, struct kobject *kobj,
 28			  const struct bin_attribute *bin_attr, char *buf,
 29			  loff_t off, 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 const BIN_ATTR_RO(state, 1);
 82
 83static ssize_t output_write(struct file *filp, struct kobject *kobj,
 84			    const 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	/*
103	 * according to the DS2413 datasheet the most significant 6 bits
104	 * should be set to "1"s, so do it now
105	 */
106	*buf = *buf | 0xFC;
107
108	while (retries--) {
109		w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
110		w1_buf[1] = *buf;
111		w1_buf[2] = ~(*buf);
112		w1_write_block(sl->master, w1_buf, 3);
113
114		if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
115			bytes_written = 1;
116			goto out;
117		}
118		if (w1_reset_resume_command(sl->master))
119			goto out; /* unrecoverable error */
120
121		dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n", retries);
122	}
123
124out:
125	mutex_unlock(&sl->master->bus_mutex);
126	dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
127		(bytes_written > 0) ? "succeeded" : "error", retries);
128	return bytes_written;
129}
130
131static const BIN_ATTR(output, 0664, NULL, output_write, 1);
132
133static const struct bin_attribute *const w1_f3a_bin_attrs[] = {
134	&bin_attr_state,
135	&bin_attr_output,
136	NULL,
137};
138
139static const struct attribute_group w1_f3a_group = {
140	.bin_attrs = w1_f3a_bin_attrs,
141};
142
143static const struct attribute_group *w1_f3a_groups[] = {
144	&w1_f3a_group,
145	NULL,
146};
147
148static const struct w1_family_ops w1_f3a_fops = {
149	.groups		= w1_f3a_groups,
150};
151
152static struct w1_family w1_family_3a = {
153	.fid = W1_FAMILY_DS2413,
154	.fops = &w1_f3a_fops,
155};
156module_w1_family(w1_family_3a);
157
158MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
159MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
160MODULE_LICENSE("GPL");
161MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));