139 lines
3.4 KiB
C
139 lines
3.4 KiB
C
/*
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* w1_ds2413.c - w1 family 3a (DS2413) driver
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* based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
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*
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* Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/device.h>
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#include <linux/types.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/w1.h>
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#define W1_FAMILY_DS2413 0x3A
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#define W1_F3A_RETRIES 3
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#define W1_F3A_FUNC_PIO_ACCESS_READ 0xF5
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#define W1_F3A_FUNC_PIO_ACCESS_WRITE 0x5A
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#define W1_F3A_SUCCESS_CONFIRM_BYTE 0xAA
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static ssize_t state_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf, loff_t off,
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size_t count)
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{
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struct w1_slave *sl = kobj_to_w1_slave(kobj);
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dev_dbg(&sl->dev,
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"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
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bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
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if (off != 0)
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return 0;
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if (!buf)
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return -EINVAL;
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mutex_lock(&sl->master->bus_mutex);
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dev_dbg(&sl->dev, "mutex locked");
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if (w1_reset_select_slave(sl)) {
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mutex_unlock(&sl->master->bus_mutex);
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return -EIO;
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}
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w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
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*buf = w1_read_8(sl->master);
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mutex_unlock(&sl->master->bus_mutex);
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dev_dbg(&sl->dev, "mutex unlocked");
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/* check for correct complement */
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if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
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return -EIO;
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else
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return 1;
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}
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static BIN_ATTR_RO(state, 1);
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static ssize_t output_write(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf,
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loff_t off, size_t count)
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{
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struct w1_slave *sl = kobj_to_w1_slave(kobj);
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u8 w1_buf[3];
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unsigned int retries = W1_F3A_RETRIES;
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if (count != 1 || off != 0)
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return -EFAULT;
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dev_dbg(&sl->dev, "locking mutex for write_output");
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mutex_lock(&sl->master->bus_mutex);
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dev_dbg(&sl->dev, "mutex locked");
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if (w1_reset_select_slave(sl))
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goto error;
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/* according to the DS2413 datasheet the most significant 6 bits
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should be set to "1"s, so do it now */
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*buf = *buf | 0xFC;
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while (retries--) {
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w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
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w1_buf[1] = *buf;
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w1_buf[2] = ~(*buf);
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w1_write_block(sl->master, w1_buf, 3);
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if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
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mutex_unlock(&sl->master->bus_mutex);
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dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries);
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return 1;
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}
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if (w1_reset_resume_command(sl->master))
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goto error;
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}
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error:
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mutex_unlock(&sl->master->bus_mutex);
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dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
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return -EIO;
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}
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static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
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static struct bin_attribute *w1_f3a_bin_attrs[] = {
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&bin_attr_state,
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&bin_attr_output,
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NULL,
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};
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static const struct attribute_group w1_f3a_group = {
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.bin_attrs = w1_f3a_bin_attrs,
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};
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static const struct attribute_group *w1_f3a_groups[] = {
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&w1_f3a_group,
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NULL,
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};
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static struct w1_family_ops w1_f3a_fops = {
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.groups = w1_f3a_groups,
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};
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static struct w1_family w1_family_3a = {
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.fid = W1_FAMILY_DS2413,
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.fops = &w1_f3a_fops,
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};
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module_w1_family(w1_family_3a);
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MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
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MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));
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