w1: new w1_ds2406 driver
Some preliminary work at making use of this driver led me to implement
CRC-16 checks on read and write to deal with the occasional glitchiness of
the 1-Wire bus. The revised driver (attached) returns an I/O error if the
CRC check fails. When reading the chip's state, either you get a valid
indication or you get an I/O error. When changing its state, either the
change is successful or an I/O error is returned.
Signed-off-by: Scott Alfter <scott@alfter.us>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index 1cdce80..fd31d2f 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -38,6 +38,13 @@
Say Y here if you want to use a 1-wire
DS2413 Dual Channel Addressable Switch device support
+config W1_SLAVE_DS2406
+ tristate "Dual Channel Addressable Switch 0x12 family support (DS2406)"
+ help
+ Say Y or M here if you want to use a 1-wire
+ DS2406 Dual Channel Addressable Switch. EPROM read/write
+ support for these devices is not implemented.
+
config W1_SLAVE_DS2423
tristate "Counter 1-wire device (DS2423)"
select CRC16
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index 06529f3..1e9989a 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -6,6 +6,7 @@
obj-$(CONFIG_W1_SLAVE_SMEM) += w1_smem.o
obj-$(CONFIG_W1_SLAVE_DS2408) += w1_ds2408.o
obj-$(CONFIG_W1_SLAVE_DS2413) += w1_ds2413.o
+obj-$(CONFIG_W1_SLAVE_DS2406) += w1_ds2406.o
obj-$(CONFIG_W1_SLAVE_DS2423) += w1_ds2423.o
obj-$(CONFIG_W1_SLAVE_DS2431) += w1_ds2431.o
obj-$(CONFIG_W1_SLAVE_DS2433) += w1_ds2433.o
diff --git a/drivers/w1/slaves/w1_ds2406.c b/drivers/w1/slaves/w1_ds2406.c
new file mode 100644
index 0000000..d488961
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds2406.c
@@ -0,0 +1,168 @@
+/*
+ * w1_ds2406.c - w1 family 12 (DS2406) driver
+ * based on w1_ds2413.c by Mariusz Bialonczyk <manio@skyboo.net>
+ *
+ * Copyright (c) 2014 Scott Alfter <scott@alfter.us>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/crc16.h>
+
+#include "../w1.h"
+#include "../w1_int.h"
+#include "../w1_family.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
+MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
+
+#define W1_F12_FUNC_READ_STATUS 0xAA
+#define W1_F12_FUNC_WRITE_STATUS 0x55
+
+static ssize_t w1_f12_read_state(
+ struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ u8 w1_buf[6]={W1_F12_FUNC_READ_STATUS, 7, 0, 0, 0, 0};
+ struct w1_slave *sl = kobj_to_w1_slave(kobj);
+ u16 crc=0;
+ int i;
+ ssize_t rtnval=1;
+
+ if (off != 0)
+ return 0;
+ if (!buf)
+ return -EINVAL;
+
+ mutex_lock(&sl->master->bus_mutex);
+
+ if (w1_reset_select_slave(sl)) {
+ mutex_unlock(&sl->master->bus_mutex);
+ return -EIO;
+ }
+
+ w1_write_block(sl->master, w1_buf, 3);
+ w1_read_block(sl->master, w1_buf+3, 3);
+ for (i=0; i<6; i++)
+ crc=crc16_byte(crc, w1_buf[i]);
+ if (crc==0xb001) /* good read? */
+ *buf=((w1_buf[3]>>5)&3)|0x30;
+ else
+ rtnval=-EIO;
+
+ mutex_unlock(&sl->master->bus_mutex);
+
+ return rtnval;
+}
+
+static ssize_t w1_f12_write_output(
+ struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct w1_slave *sl = kobj_to_w1_slave(kobj);
+ u8 w1_buf[6]={W1_F12_FUNC_WRITE_STATUS, 7, 0, 0, 0, 0};
+ u16 crc=0;
+ int i;
+ ssize_t rtnval=1;
+
+ if (count != 1 || off != 0)
+ return -EFAULT;
+
+ mutex_lock(&sl->master->bus_mutex);
+
+ if (w1_reset_select_slave(sl)) {
+ mutex_unlock(&sl->master->bus_mutex);
+ return -EIO;
+ }
+
+ w1_buf[3] = (((*buf)&3)<<5)|0x1F;
+ w1_write_block(sl->master, w1_buf, 4);
+ w1_read_block(sl->master, w1_buf+4, 2);
+ for (i=0; i<6; i++)
+ crc=crc16_byte(crc, w1_buf[i]);
+ if (crc==0xb001) /* good read? */
+ w1_write_8(sl->master, 0xFF);
+ else
+ rtnval=-EIO;
+
+ mutex_unlock(&sl->master->bus_mutex);
+ return rtnval;
+}
+
+#define NB_SYSFS_BIN_FILES 2
+static struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
+ {
+ .attr = {
+ .name = "state",
+ .mode = S_IRUGO,
+ },
+ .size = 1,
+ .read = w1_f12_read_state,
+ },
+ {
+ .attr = {
+ .name = "output",
+ .mode = S_IRUGO | S_IWUSR | S_IWGRP,
+ },
+ .size = 1,
+ .write = w1_f12_write_output,
+ }
+};
+
+static int w1_f12_add_slave(struct w1_slave *sl)
+{
+ int err = 0;
+ int i;
+
+ for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
+ err = sysfs_create_bin_file(
+ &sl->dev.kobj,
+ &(w1_f12_sysfs_bin_files[i]));
+ if (err)
+ while (--i >= 0)
+ sysfs_remove_bin_file(&sl->dev.kobj,
+ &(w1_f12_sysfs_bin_files[i]));
+ return err;
+}
+
+static void w1_f12_remove_slave(struct w1_slave *sl)
+{
+ int i;
+ for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
+ sysfs_remove_bin_file(&sl->dev.kobj,
+ &(w1_f12_sysfs_bin_files[i]));
+}
+
+static struct w1_family_ops w1_f12_fops = {
+ .add_slave = w1_f12_add_slave,
+ .remove_slave = w1_f12_remove_slave,
+};
+
+static struct w1_family w1_family_12 = {
+ .fid = W1_FAMILY_DS2406,
+ .fops = &w1_f12_fops,
+};
+
+static int __init w1_f12_init(void)
+{
+ return w1_register_family(&w1_family_12);
+}
+
+static void __exit w1_f12_exit(void)
+{
+ w1_unregister_family(&w1_family_12);
+}
+
+module_init(w1_f12_init);
+module_exit(w1_f12_exit);
diff --git a/drivers/w1/w1_family.h b/drivers/w1/w1_family.h
index 26ca134..0d18365 100644
--- a/drivers/w1/w1_family.h
+++ b/drivers/w1/w1_family.h
@@ -40,6 +40,7 @@
#define W1_FAMILY_DS2760 0x30
#define W1_FAMILY_DS2780 0x32
#define W1_FAMILY_DS2413 0x3A
+#define W1_FAMILY_DS2406 0x12
#define W1_THERM_DS1825 0x3B
#define W1_FAMILY_DS2781 0x3D
#define W1_THERM_DS28EA00 0x42