354 lines
9.1 KiB
C
354 lines
9.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* w1_ds2408.c - w1 family 29 (DS2408) driver
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*
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* Copyright (c) 2010 Jean-Francois Dagenais <dagenaisj@sonatest.com>
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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_DS2408 0x29
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#define W1_F29_RETRIES 3
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#define W1_F29_REG_LOGIG_STATE 0x88 /* R */
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#define W1_F29_REG_OUTPUT_LATCH_STATE 0x89 /* R */
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#define W1_F29_REG_ACTIVITY_LATCH_STATE 0x8A /* R */
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#define W1_F29_REG_COND_SEARCH_SELECT_MASK 0x8B /* RW */
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#define W1_F29_REG_COND_SEARCH_POL_SELECT 0x8C /* RW */
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#define W1_F29_REG_CONTROL_AND_STATUS 0x8D /* RW */
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#define W1_F29_FUNC_READ_PIO_REGS 0xF0
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#define W1_F29_FUNC_CHANN_ACCESS_READ 0xF5
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#define W1_F29_FUNC_CHANN_ACCESS_WRITE 0x5A
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/* also used to write the control/status reg (0x8D): */
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#define W1_F29_FUNC_WRITE_COND_SEARCH_REG 0xCC
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#define W1_F29_FUNC_RESET_ACTIVITY_LATCHES 0xC3
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#define W1_F29_SUCCESS_CONFIRM_BYTE 0xAA
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static int _read_reg(struct w1_slave *sl, u8 address, unsigned char* buf)
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{
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u8 wrbuf[3];
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dev_dbg(&sl->dev,
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"Reading with slave: %p, reg addr: %0#4x, buff addr: %p",
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sl, (unsigned int)address, buf);
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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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wrbuf[0] = W1_F29_FUNC_READ_PIO_REGS;
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wrbuf[1] = address;
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wrbuf[2] = 0;
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w1_write_block(sl->master, wrbuf, 3);
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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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return 1;
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}
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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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dev_dbg(&kobj_to_w1_slave(kobj)->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 (count != 1 || off != 0)
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return -EFAULT;
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return _read_reg(kobj_to_w1_slave(kobj), W1_F29_REG_LOGIG_STATE, buf);
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}
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static ssize_t output_read(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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dev_dbg(&kobj_to_w1_slave(kobj)->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 (count != 1 || off != 0)
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return -EFAULT;
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return _read_reg(kobj_to_w1_slave(kobj),
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W1_F29_REG_OUTPUT_LATCH_STATE, buf);
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}
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static ssize_t activity_read(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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dev_dbg(&kobj_to_w1_slave(kobj)->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 (count != 1 || off != 0)
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return -EFAULT;
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return _read_reg(kobj_to_w1_slave(kobj),
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W1_F29_REG_ACTIVITY_LATCH_STATE, buf);
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}
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static ssize_t cond_search_mask_read(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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dev_dbg(&kobj_to_w1_slave(kobj)->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 (count != 1 || off != 0)
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return -EFAULT;
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return _read_reg(kobj_to_w1_slave(kobj),
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W1_F29_REG_COND_SEARCH_SELECT_MASK, buf);
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}
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static ssize_t cond_search_polarity_read(struct file *filp,
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struct kobject *kobj,
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struct bin_attribute *bin_attr,
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char *buf, loff_t off, size_t count)
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{
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if (count != 1 || off != 0)
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return -EFAULT;
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return _read_reg(kobj_to_w1_slave(kobj),
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W1_F29_REG_COND_SEARCH_POL_SELECT, buf);
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}
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static ssize_t status_control_read(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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if (count != 1 || off != 0)
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return -EFAULT;
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return _read_reg(kobj_to_w1_slave(kobj),
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W1_F29_REG_CONTROL_AND_STATUS, buf);
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}
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#ifdef CONFIG_W1_SLAVE_DS2408_READBACK
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static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)
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{
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u8 w1_buf[3];
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if (w1_reset_resume_command(sl->master))
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return false;
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w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
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w1_buf[1] = W1_F29_REG_OUTPUT_LATCH_STATE;
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w1_buf[2] = 0;
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w1_write_block(sl->master, w1_buf, 3);
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return (w1_read_8(sl->master) == expected);
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}
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#else
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static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)
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{
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return true;
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}
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#endif
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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_F29_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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do {
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w1_buf[0] = W1_F29_FUNC_CHANN_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_F29_SUCCESS_CONFIRM_BYTE &&
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optional_read_back_valid(sl, *buf)) {
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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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/* try again, the slave is ready for a command */
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} while (--retries);
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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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/**
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* Writing to the activity file resets the activity latches.
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*/
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static ssize_t activity_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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unsigned int retries = W1_F29_RETRIES;
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if (count != 1 || off != 0)
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return -EFAULT;
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mutex_lock(&sl->master->bus_mutex);
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if (w1_reset_select_slave(sl))
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goto error;
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while (retries--) {
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w1_write_8(sl->master, W1_F29_FUNC_RESET_ACTIVITY_LATCHES);
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if (w1_read_8(sl->master) == W1_F29_SUCCESS_CONFIRM_BYTE) {
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mutex_unlock(&sl->master->bus_mutex);
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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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return -EIO;
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}
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static ssize_t status_control_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[4];
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unsigned int retries = W1_F29_RETRIES;
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if (count != 1 || off != 0)
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return -EFAULT;
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mutex_lock(&sl->master->bus_mutex);
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if (w1_reset_select_slave(sl))
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goto error;
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while (retries--) {
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w1_buf[0] = W1_F29_FUNC_WRITE_COND_SEARCH_REG;
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w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS;
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w1_buf[2] = 0;
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w1_buf[3] = *buf;
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w1_write_block(sl->master, w1_buf, 4);
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if (w1_reset_resume_command(sl->master))
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goto error;
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w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
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w1_buf[1] = W1_F29_REG_CONTROL_AND_STATUS;
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w1_buf[2] = 0;
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w1_write_block(sl->master, w1_buf, 3);
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if (w1_read_8(sl->master) == *buf) {
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/* success! */
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mutex_unlock(&sl->master->bus_mutex);
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return 1;
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}
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}
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error:
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mutex_unlock(&sl->master->bus_mutex);
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return -EIO;
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}
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/*
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* This is a special sequence we must do to ensure the P0 output is not stuck
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* in test mode. This is described in rev 2 of the ds2408's datasheet
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* (http://datasheets.maximintegrated.com/en/ds/DS2408.pdf) under
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* "APPLICATION INFORMATION/Power-up timing".
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*/
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static int w1_f29_disable_test_mode(struct w1_slave *sl)
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{
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int res;
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u8 magic[10] = {0x96, };
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u64 rn = le64_to_cpu(*((u64*)&sl->reg_num));
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memcpy(&magic[1], &rn, 8);
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magic[9] = 0x3C;
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mutex_lock(&sl->master->bus_mutex);
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res = w1_reset_bus(sl->master);
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if (res)
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goto out;
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w1_write_block(sl->master, magic, ARRAY_SIZE(magic));
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res = w1_reset_bus(sl->master);
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out:
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mutex_unlock(&sl->master->bus_mutex);
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return res;
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}
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static BIN_ATTR_RO(state, 1);
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static BIN_ATTR_RW(output, 1);
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static BIN_ATTR_RW(activity, 1);
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static BIN_ATTR_RO(cond_search_mask, 1);
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static BIN_ATTR_RO(cond_search_polarity, 1);
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static BIN_ATTR_RW(status_control, 1);
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static struct bin_attribute *w1_f29_bin_attrs[] = {
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&bin_attr_state,
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&bin_attr_output,
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&bin_attr_activity,
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&bin_attr_cond_search_mask,
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&bin_attr_cond_search_polarity,
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&bin_attr_status_control,
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NULL,
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};
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static const struct attribute_group w1_f29_group = {
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.bin_attrs = w1_f29_bin_attrs,
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};
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static const struct attribute_group *w1_f29_groups[] = {
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&w1_f29_group,
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NULL,
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};
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static const struct w1_family_ops w1_f29_fops = {
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.add_slave = w1_f29_disable_test_mode,
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.groups = w1_f29_groups,
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};
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static struct w1_family w1_family_29 = {
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.fid = W1_FAMILY_DS2408,
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.fops = &w1_f29_fops,
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};
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module_w1_family(w1_family_29);
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MODULE_AUTHOR("Jean-Francois Dagenais <dagenaisj@sonatest.com>");
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MODULE_DESCRIPTION("w1 family 29 driver for DS2408 8 Pin IO");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2408));
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