From 94859308a21b2bbf3d7c48789513c0c4a9ea7de1 Mon Sep 17 00:00:00 2001 From: Scott Alfter Date: Tue, 17 Jun 2014 20:42:05 +0000 Subject: [PATCH] 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 Acked-by: Evgeniy Polyakov Signed-off-by: Greg Kroah-Hartman --- Documentation/w1/slaves/w1_ds2406 | 25 +++++ drivers/w1/slaves/Kconfig | 7 ++ drivers/w1/slaves/Makefile | 1 + drivers/w1/slaves/w1_ds2406.c | 168 ++++++++++++++++++++++++++++++ drivers/w1/w1_family.h | 1 + 5 files changed, 202 insertions(+) create mode 100644 Documentation/w1/slaves/w1_ds2406 create mode 100644 drivers/w1/slaves/w1_ds2406.c diff --git a/Documentation/w1/slaves/w1_ds2406 b/Documentation/w1/slaves/w1_ds2406 new file mode 100644 index 000000000000..8137fe6f6c3d --- /dev/null +++ b/Documentation/w1/slaves/w1_ds2406 @@ -0,0 +1,25 @@ +w1_ds2406 kernel driver +======================= + +Supported chips: + * Maxim DS2406 (and other family 0x12) addressable switches + +Author: Scott Alfter + +Description +----------- + +The w1_ds2406 driver allows connected devices to be switched on and off. +These chips also provide 128 bytes of OTP EPROM, but reading/writing it is +not supported. In TSOC-6 form, the DS2406 provides two switch outputs and +can be provided with power on a dedicated input. In TO-92 form, it provides +one output and uses parasitic power only. + +The driver provides two sysfs files. state is readable; it gives the +current state of each switch, with PIO A in bit 0 and PIO B in bit 1. The +driver ORs this state with 0x30, so shell scripts get an ASCII 0/1/2/3 to +work with. output is writable; bits 0 and 1 control PIO A and B, +respectively. Bits 2-7 are ignored, so it's safe to write ASCII data. + +CRCs are checked on read and write. Failed checks cause an I/O error to be +returned. On a failed write, the switch status is not changed. diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig index 1cdce80b6abf..fd31d2f32c48 100644 --- a/drivers/w1/slaves/Kconfig +++ b/drivers/w1/slaves/Kconfig @@ -38,6 +38,13 @@ config W1_SLAVE_DS2413 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 06529f3157ab..1e9989afe7bf 100644 --- a/drivers/w1/slaves/Makefile +++ b/drivers/w1/slaves/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_W1_SLAVE_THERM) += w1_therm.o obj-$(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 000000000000..d488961a8c90 --- /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 + * + * Copyright (c) 2014 Scott Alfter + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../w1.h" +#include "../w1_int.h" +#include "../w1_family.h" + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Scott Alfter "); +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 26ca1343055b..0d18365b61ad 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 -- 2.20.1