Date:	Thu, 28 Oct 2010 22:52:53 +0200
From:	Maciej Szmigiero <mhej@...pl>
To:	johnpol@....mipt.ru
CC:	linux-kernel@...r.kernel.org
Subject: [W1] a driver for DS2405 chip

[W1] a driver for DS2405 chip

This is a driver for DS2405 1-wire single-channel addressable switch / PIO.
DS2405 can also work as single-channel binary remote sensor.

Signed-off-by: Maciej Szmigiero <mhej@...pl>

--- a/drivers/w1/w1_family.h	2009-06-10 05:05:27.000000000 +0200
+++ b/drivers/w1/w1_family.h	2009-12-13 22:23:32.994770399 +0100
@@ -28,6 +28,7 @@
 
 #define W1_FAMILY_DEFAULT	0
 #define W1_FAMILY_SMEM_01	0x01
+#define W1_FAMILY_DS2405	0x05
 #define W1_FAMILY_SMEM_81	0x81
 #define W1_THERM_DS18S20 	0x10
 #define W1_THERM_DS1822  	0x22
--- a/drivers/w1/w1_io.c	2009-06-10 05:05:27.000000000 +0200
+++ b/drivers/w1/w1_io.c	2009-12-15 22:32:48.362801835 +0100
@@ -210,6 +210,7 @@
 		return retval;
 	}
 }
+EXPORT_SYMBOL_GPL(w1_triplet);
 
 /**
  * Reads 8 bits.
--- /dev/null	2010-10-28 22:18:50.899999998 +0200
+++ b/drivers/w1/slaves/w1_ds2405.c	2010-10-28 22:42:13.000000000 +0200
@@ -0,0 +1,251 @@
+/*
+ *	w1_ds2405.c
+ *
+ * Copyright (c) 2009 Maciej Szmigiero <mhej@...pl>
+ * Based on w1_therm.c copyright (c) 2004 Evgeniy Polyakov <johnpol@....mipt.ru>
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the therms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/sched.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+
+#include "../w1.h"
+#include "../w1_int.h"
+#include "../w1_family.h"
+
+static int w1_ds2405_select(struct w1_slave *sl, int only_active)
+{
+	struct w1_master *dev = sl->master;
+	int ret;
+
+	if (w1_reset_bus(dev) != 0)
+		return 0;
+
+	/* We cannot use normal Match ROM command */
+	/* since doing so would toggle PIO state */
+	w1_write_8(dev, only_active ? W1_ALARM_SEARCH : W1_SEARCH);
+
+	do {
+		u64 dev_addr = cpu_to_le64(((u64)sl->reg_num.crc<<(8+48))
+					| ((u64)sl->reg_num.id<<8)
+					| sl->reg_num.family);
+		u8 bit_ctr;
+
+		for (bit_ctr = 0; bit_ctr < 64; bit_ctr++) {
+			int bit2send = !!(dev_addr & 1LL<<bit_ctr);
+			ret = w1_triplet(dev, bit2send);
+
+			if ((ret & 3) == 3) /* no devices found */
+				return 0;
+
+			if ((!!(ret & 4)) != bit2send)
+				/* wrong direction taken - no such device */
+				return 0;
+		}
+	} while (0);
+
+	return 1;
+}
+
+static int w1_ds2405_read_pio(struct w1_slave *sl)
+{
+	if (w1_ds2405_select(sl, 1))
+		return 0; /* "active" means PIO is low */
+
+	if (w1_ds2405_select(sl, 0))
+		return 1;
+	else
+		return -ENODEV;
+}
+
+static ssize_t w1_ds2405_read_sensed_file(struct device *device,
+	struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+	struct w1_master *dev = sl->master;
+
+	int ret;
+	ssize_t f_retval;
+	u8 state;
+
+	ret = mutex_lock_interruptible(&dev->mutex);
+	if (ret)
+		return ret;
+
+	if (!w1_ds2405_select(sl, 0)) {
+		f_retval = -ENODEV;
+		goto out_unlock;
+	}
+
+	state = w1_read_8(dev);
+
+	f_retval = snprintf(buf, PAGE_SIZE, "%u\n", !!(state));
+
+out_unlock:
+	w1_reset_bus(dev);
+	mutex_unlock(&dev->mutex);
+
+	return f_retval;
+}
+
+static ssize_t w1_ds2405_read_pio_file(struct device *device,
+	struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+	struct w1_master *dev = sl->master;
+
+	int ret;
+	ssize_t f_retval;
+
+	ret = mutex_lock_interruptible(&dev->mutex);
+	if (ret)
+		return ret;
+
+	ret = w1_ds2405_read_pio(sl);
+	if (ret < 0) {
+		f_retval = ret;
+		goto out_unlock;
+	}
+
+	f_retval = snprintf(buf, PAGE_SIZE, "%d\n", ret);
+
+out_unlock:
+	w1_reset_bus(dev);
+	mutex_unlock(&dev->mutex);
+
+	return f_retval;
+}
+
+static ssize_t w1_ds2405_write_pio_file(struct device *device,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+	struct w1_master *dev = sl->master;
+
+	int ret, current_pio;
+	unsigned int val;
+	ssize_t f_retval;
+
+	if (count < 1)
+		return -EINVAL;
+
+	/* fill_write_buffer() in fs/sysfs/file.c */
+	/* keeps the buffer null-terminated */
+	if (sscanf(buf, " %u%n", &val, &ret) < 1)
+		return -EINVAL;
+
+	if ((val != 0) && (val != 1))
+		return -EINVAL;
+
+	f_retval = ret;
+
+	ret = mutex_lock_interruptible(&dev->mutex);
+	if (ret)
+		return ret;
+
+	current_pio = w1_ds2405_read_pio(sl);
+	if (current_pio < 0) {
+		f_retval = current_pio;
+		goto out_unlock;
+	}
+
+	if (current_pio == val)
+		goto out_unlock;
+
+	if (w1_reset_bus(dev) != 0) {
+		f_retval = -ENODEV;
+		goto out_unlock;
+	}
+
+	do {
+		u64 dev_addr = cpu_to_le64(((u64)sl->reg_num.crc<<(8+48))
+			     | ((u64)sl->reg_num.id<<8) | sl->reg_num.family);
+
+		w1_write_8(dev, W1_MATCH_ROM);
+		w1_write_block(dev, (u8 *)&dev_addr, 8);
+	} while (0);
+
+out_unlock:
+	w1_reset_bus(dev);
+	mutex_unlock(&dev->mutex);
+
+	return f_retval;
+}
+
+static DEVICE_ATTR(sensed, S_IRUSR | S_IRGRP, w1_ds2405_read_sensed_file, NULL);
+static DEVICE_ATTR(PIO, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP,
+		    w1_ds2405_read_pio_file, w1_ds2405_write_pio_file);
+
+static int w1_ds2405_add_slave(struct w1_slave *sl)
+{
+	int err;
+
+	err = device_create_file(&sl->dev, &dev_attr_sensed);
+	if (err)
+		return err;
+
+	err = device_create_file(&sl->dev, &dev_attr_PIO);
+	if (err) {
+		device_remove_file(&sl->dev, &dev_attr_sensed);
+		return err;
+	}
+
+	return 0;
+}
+
+static void w1_ds2405_remove_slave(struct w1_slave *sl)
+{
+	device_remove_file(&sl->dev, &dev_attr_sensed);
+	device_remove_file(&sl->dev, &dev_attr_PIO);
+}
+
+
+static struct w1_family_ops w1_ds2405_fops = {
+	.add_slave	= w1_ds2405_add_slave,
+	.remove_slave	= w1_ds2405_remove_slave,
+};
+
+
+static struct w1_family w1_family_ds2405 = {
+	.fid = W1_FAMILY_DS2405,
+	.fops = &w1_ds2405_fops,
+};
+
+static int __init w1_ds2405_init(void)
+{
+	return w1_register_family(&w1_family_ds2405);
+}
+
+static void __exit w1_ds2405_fini(void)
+{
+
+	w1_unregister_family(&w1_family_ds2405);
+}
+
+module_init(w1_ds2405_init);
+module_exit(w1_ds2405_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Maciej Szmigiero <mhej@...pl>");
+MODULE_DESCRIPTION("Driver for 1-wire Dallas DS2405 PIO");
--- a/drivers/w1/slaves/Makefile	2010-08-02 00:11:14.000000000 +0200
+++ b/drivers/w1/slaves/Makefile	2010-10-28 22:39:13.000000000 +0200
@@ -4,6 +4,7 @@
 
 obj-$(CONFIG_W1_SLAVE_THERM)	+= w1_therm.o
 obj-$(CONFIG_W1_SLAVE_SMEM)	+= w1_smem.o
+obj-$(CONFIG_W1_SLAVE_DS2405)	+= w1_ds2405.o
 obj-$(CONFIG_W1_SLAVE_DS2431)	+= w1_ds2431.o
 obj-$(CONFIG_W1_SLAVE_DS2433)	+= w1_ds2433.o
 obj-$(CONFIG_W1_SLAVE_DS2760)	+= w1_ds2760.o
--- a/drivers/w1/slaves/Kconfig	2010-08-02 00:11:14.000000000 +0200
+++ b/drivers/w1/slaves/Kconfig	2010-10-28 22:37:55.000000000 +0200
@@ -16,6 +16,14 @@
 	  Say Y here if you want to connect 1-wire
 	  simple 64bit memory rom(ds2401/ds2411/ds1990*) to your wire.
 
+config W1_SLAVE_DS2405
+	tristate "DS2405 Addressable Switch / PIO"
+	help
+	  Say Y here if you want to build driver for 1-wire
+	  single-channel addressable switch / PIO.
+	  This device can also work as single-channel
+	  binary remote sensor.
+
 config W1_SLAVE_DS2431
 	tristate "1kb EEPROM family support (DS2431)"
 	help


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