c50d09a861
The state_read() was calling PIO_ACCESS_READ once and bail out if it failed for this first time. This commit is improving this to trying more times before it give up, similarly as the write call is currently doing. Signed-off-by: Mariusz Bialonczyk <manio@skyboo.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
153 lines
3.8 KiB
C
153 lines
3.8 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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unsigned int retries = W1_F3A_RETRIES;
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ssize_t bytes_read = -EIO;
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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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goto out;
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while (retries--) {
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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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/* check for correct complement */
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if ((*buf & 0x0F) == ((~*buf >> 4) & 0x0F)) {
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bytes_read = 1;
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goto out;
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}
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if (w1_reset_resume_command(sl->master))
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goto out; /* unrecoverable error */
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dev_warn(&sl->dev, "PIO_ACCESS_READ error, retries left: %d\n", retries);
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}
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out:
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mutex_unlock(&sl->master->bus_mutex);
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dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
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(bytes_read > 0) ? "succeeded" : "error", retries);
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return bytes_read;
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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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ssize_t bytes_written = -EIO;
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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 out;
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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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bytes_written = 1;
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goto out;
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}
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if (w1_reset_resume_command(sl->master))
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goto out; /* unrecoverable error */
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dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n", retries);
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}
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out:
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mutex_unlock(&sl->master->bus_mutex);
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dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
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(bytes_written > 0) ? "succeeded" : "error", retries);
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return bytes_written;
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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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