401 lines
9.6 KiB
C
401 lines
9.6 KiB
C
/*
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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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* 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 "../w1.h"
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#include "../w1_int.h"
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#include "../w1_family.h"
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MODULE_LICENSE("GPL");
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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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#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 w1_f29_read_state(
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struct file *filp, 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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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 w1_f29_read_output(
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struct file *filp, 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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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 w1_f29_read_activity(
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struct file *filp, 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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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 w1_f29_read_cond_search_mask(
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struct file *filp, 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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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 w1_f29_read_cond_search_polarity(
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struct file *filp, 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 w1_f29_read_status_control(
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struct file *filp, 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_CONTROL_AND_STATUS, buf);
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}
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static ssize_t w1_f29_write_output(
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struct file *filp, 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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struct w1_slave *sl = kobj_to_w1_slave(kobj);
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u8 w1_buf[3];
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u8 readBack;
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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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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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while (retries--) {
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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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readBack = w1_read_8(sl->master);
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/* here the master could read another byte which
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would be the PIO reg (the actual pin logic state)
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since in this driver we don't know which pins are
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in and outs, there's no value to read the state and
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compare. with (*buf) so end this command abruptly: */
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if (w1_reset_resume_command(sl->master))
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goto error;
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if (readBack != 0xAA) {
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/* try again, the slave is ready for a command */
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continue;
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}
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/* go read back the output latches */
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/* (the direct effect of the write above) */
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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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/* read the result of the READ_PIO_REGS command */
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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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dev_dbg(&sl->dev,
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"mutex unlocked, retries:%d", retries);
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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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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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/**
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* Writing to the activity file resets the activity latches.
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*/
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static ssize_t w1_f29_write_activity(
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struct file *filp, 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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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 w1_f29_write_status_control(
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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,
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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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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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#define NB_SYSFS_BIN_FILES 6
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static struct bin_attribute w1_f29_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
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{
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.attr = {
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.name = "state",
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.mode = S_IRUGO,
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},
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.size = 1,
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.read = w1_f29_read_state,
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},
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{
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.attr = {
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.name = "output",
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.mode = S_IRUGO | S_IWUSR | S_IWGRP,
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},
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.size = 1,
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.read = w1_f29_read_output,
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.write = w1_f29_write_output,
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},
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{
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.attr = {
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.name = "activity",
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.mode = S_IRUGO,
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},
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.size = 1,
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.read = w1_f29_read_activity,
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.write = w1_f29_write_activity,
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},
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{
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.attr = {
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.name = "cond_search_mask",
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.mode = S_IRUGO,
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},
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.size = 1,
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.read = w1_f29_read_cond_search_mask,
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},
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{
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.attr = {
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.name = "cond_search_polarity",
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.mode = S_IRUGO,
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},
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.size = 1,
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.read = w1_f29_read_cond_search_polarity,
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},
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{
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.attr = {
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.name = "status_control",
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.mode = S_IRUGO | S_IWUSR | S_IWGRP,
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},
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.size = 1,
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.read = w1_f29_read_status_control,
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.write = w1_f29_write_status_control,
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}
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};
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static int w1_f29_add_slave(struct w1_slave *sl)
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{
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int err = 0;
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int i;
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for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
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err = sysfs_create_bin_file(
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&sl->dev.kobj,
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&(w1_f29_sysfs_bin_files[i]));
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if (err)
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while (--i >= 0)
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sysfs_remove_bin_file(&sl->dev.kobj,
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&(w1_f29_sysfs_bin_files[i]));
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return err;
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}
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static void w1_f29_remove_slave(struct w1_slave *sl)
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{
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int i;
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for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
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sysfs_remove_bin_file(&sl->dev.kobj,
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&(w1_f29_sysfs_bin_files[i]));
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}
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static struct w1_family_ops w1_f29_fops = {
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.add_slave = w1_f29_add_slave,
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.remove_slave = w1_f29_remove_slave,
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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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static int __init w1_f29_init(void)
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{
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return w1_register_family(&w1_family_29);
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}
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static void __exit w1_f29_exit(void)
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{
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w1_unregister_family(&w1_family_29);
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}
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module_init(w1_f29_init);
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module_exit(w1_f29_exit);
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