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Fixed MTP to work with TWRP

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00-INDEX
- This file
slaves/
- Drivers that provide support for specific family codes.
masters/
- Individual chips providing 1-wire busses.
w1.generic
- The 1-wire (w1) bus
w1.netlink
- Userspace communication protocol over connector [1].

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00-INDEX
- This file
ds2482
- The Maxim/Dallas Semiconductor DS2482 provides 1-wire busses.
ds2490
- The Maxim/Dallas Semiconductor DS2490 builds USB <-> W1 bridges.
mxc-w1
- W1 master controller driver found on Freescale MX2/MX3 SoCs
omap-hdq
- HDQ/1-wire module of TI OMAP 2430/3430.
w1-gpio
- GPIO 1-wire bus master driver.

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Kernel driver ds2482
====================
Supported chips:
* Maxim DS2482-100, Maxim DS2482-800
Prefix: 'ds2482'
Addresses scanned: None
Datasheets:
http://datasheets.maxim-ic.com/en/ds/DS2482-100.pdf
http://datasheets.maxim-ic.com/en/ds/DS2482-800.pdf
Author: Ben Gardner <bgardner@wabtec.com>
Description
-----------
The Maxim/Dallas Semiconductor DS2482 is a I2C device that provides
one (DS2482-100) or eight (DS2482-800) 1-wire busses.
General Remarks
---------------
Valid addresses are 0x18, 0x19, 0x1a, and 0x1b.
However, the device cannot be detected without writing to the i2c bus, so no
detection is done. You should instantiate the device explicitly.
$ modprobe ds2482
$ echo ds2482 0x18 > /sys/bus/i2c/devices/i2c-0/new_device

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Kernel driver ds2490
====================
Supported chips:
* Maxim DS2490 based
Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Description
-----------
The Maxim/Dallas Semiconductor DS2490 is a chip
which allows to build USB <-> W1 bridges.
DS9490(R) is a USB <-> W1 bus master device
which has 0x81 family ID integrated chip and DS2490
low-level operational chip.
Notes and limitations.
- The weak pullup current is a minimum of 0.9mA and maximum of 6.0mA.
- The 5V strong pullup is supported with a minimum of 5.9mA and a
maximum of 30.4 mA. (From DS2490.pdf)
- The hardware will detect when devices are attached to the bus on the
next bus (reset?) operation, however only a message is printed as
the core w1 code doesn't make use of the information. Connecting
one device tends to give multiple new device notifications.
- The number of USB bus transactions could be reduced if w1_reset_send
was added to the API. The name is just a suggestion. It would take
a write buffer and a read buffer (along with sizes) as arguments.
The ds2490 block I/O command supports reset, write buffer, read
buffer, and strong pullup all in one command, instead of the current
1 reset bus, 2 write the match rom command and slave rom id, 3 block
write and read data. The write buffer needs to have the match rom
command and slave rom id prepended to the front of the requested
write buffer, both of which are known to the driver.
- The hardware supports normal, flexible, and overdrive bus
communication speeds, but only the normal is supported.
- The registered w1_bus_master functions don't define error
conditions. If a bus search is in progress and the ds2490 is
removed it can produce a good amount of error output before the bus
search finishes.
- The hardware supports detecting some error conditions, such as
short, alarming presence on reset, and no presence on reset, but the
driver doesn't query those values.
- The ds2490 specification doesn't cover short bulk in reads in
detail, but my observation is if fewer bytes are requested than are
available, the bulk read will return an error and the hardware will
clear the entire bulk in buffer. It would be possible to read the
maximum buffer size to not run into this error condition, only extra
bytes in the buffer is a logic error in the driver. The code should
should match reads and writes as well as data sizes. Reads and
writes are serialized and the status verifies that the chip is idle
(and data is available) before the read is executed, so it should
not happen.
- Running x86_64 2.6.24 UHCI under qemu 0.9.0 under x86_64 2.6.22-rc6
with a OHCI controller, ds2490 running in the guest would operate
normally the first time the module was loaded after qemu attached
the ds2490 hardware, but if the module was unloaded, then reloaded
most of the time one of the bulk out or in, and usually the bulk in
would fail. qemu sets a 50ms timeout and the bulk in would timeout
even when the status shows data available. A bulk out write would
show a successful completion, but the ds2490 status register would
show 0 bytes written. Detaching qemu from the ds2490 hardware and
reattaching would clear the problem. usbmon output in the guest and
host did not explain the problem. My guess is a bug in either qemu
or the host OS and more likely the host OS.
-- 03-06-2008 David Fries <David@Fries.net>

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Kernel driver mxc_w1
====================
Supported chips:
* Freescale MX27, MX31 and probably other i.MX SoCs
Datasheets:
http://www.freescale.com/files/32bit/doc/data_sheet/MCIMX31.pdf?fpsp=1
http://cache.freescale.com/files/dsp/doc/archive/MCIMX27.pdf?fsrch=1&WT_TYPE=
Data%20Sheets&WT_VENDOR=FREESCALE&WT_FILE_FORMAT=pdf&WT_ASSET=Documentation
Author: Originally based on Freescale code, prepared for mainline by
Sascha Hauer <s.hauer@pengutronix.de>

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Kernel driver for omap HDQ/1-wire module.
========================================
Supported chips:
================
HDQ/1-wire controller on the TI OMAP 2430/3430 platforms.
A useful link about HDQ basics:
===============================
http://focus.ti.com/lit/an/slua408a/slua408a.pdf
Description:
============
The HDQ/1-Wire module of TI OMAP2430/3430 platforms implement the hardware
protocol of the master functions of the Benchmark HDQ and the Dallas
Semiconductor 1-Wire protocols. These protocols use a single wire for
communication between the master (HDQ/1-Wire controller) and the slave
(HDQ/1-Wire external compliant device).
A typical application of the HDQ/1-Wire module is the communication with battery
monitor (gas gauge) integrated circuits.
The controller supports operation in both HDQ and 1-wire mode. The essential
difference between the HDQ and 1-wire mode is how the slave device responds to
initialization pulse.In HDQ mode, the firmware does not require the host to
create an initialization pulse to the slave.However, the slave can be reset by
using an initialization pulse (also referred to as a break pulse).The slave
does not respond with a presence pulse as it does in the 1-Wire protocol.
Remarks:
========
The driver (drivers/w1/masters/omap_hdq.c) supports the HDQ mode of the
controller. In this mode, as we can not read the ID which obeys the W1
spec(family:id:crc), a module parameter can be passed to the driver which will
be used to calculate the CRC and pass back an appropriate slave ID to the W1
core.
By default the master driver and the BQ slave i/f
driver(drivers/w1/slaves/w1_bq27000.c) sets the ID to 1.
Please note to load both the modules with a different ID if required, but note
that the ID used should be same for both master and slave driver loading.
e.g:
insmod omap_hdq.ko W1_ID=2
inamod w1_bq27000.ko F_ID=2

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Kernel driver w1-gpio
=====================
Author: Ville Syrjala <syrjala@sci.fi>
Description
-----------
GPIO 1-wire bus master driver. The driver uses the GPIO API to control the
wire and the GPIO pin can be specified using platform data.
Example (mach-at91)
-------------------
#include <linux/w1-gpio.h>
static struct w1_gpio_platform_data foo_w1_gpio_pdata = {
.pin = AT91_PIN_PB20,
.is_open_drain = 1,
};
static struct platform_device foo_w1_device = {
.name = "w1-gpio",
.id = -1,
.dev.platform_data = &foo_w1_gpio_pdata,
};
...
at91_set_GPIO_periph(foo_w1_gpio_pdata.pin, 1);
at91_set_multi_drive(foo_w1_gpio_pdata.pin, 1);
platform_device_register(&foo_w1_device);

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00-INDEX
- This file
w1_therm
- The Maxim/Dallas Semiconductor ds18*20 temperature sensor.
w1_ds2423
- The Maxim/Dallas Semiconductor ds2423 counter device.
w1_ds28e04
- The Maxim/Dallas Semiconductor ds28e04 eeprom.

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w1_ds2406 kernel driver
=======================
Supported chips:
* Maxim DS2406 (and other family 0x12) addressable switches
Author: Scott Alfter <scott@alfter.us>
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.

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Kernel driver w1_ds2423
=======================
Supported chips:
* Maxim DS2423 based counter devices.
supported family codes:
W1_THERM_DS2423 0x1D
Author: Mika Laitio <lamikr@pilppa.org>
Description
-----------
Support is provided through the sysfs w1_slave file. Each opening and
read sequence of w1_slave file initiates the read of counters and ram
available in DS2423 pages 12 - 15.
Result of each page is provided as an ASCII output where each counter
value and associated ram buffer is outpputed to own line.
Each lines will contain the values of 42 bytes read from the counter and
memory page along the crc=YES or NO for indicating whether the read operation
was successful and CRC matched.
If the operation was successful, there is also in the end of each line
a counter value expressed as an integer after c=
Meaning of 42 bytes represented is following:
- 1 byte from ram page
- 4 bytes for the counter value
- 4 zero bytes
- 2 bytes for crc16 which was calculated from the data read since the previous crc bytes
- 31 remaining bytes from the ram page
- crc=YES/NO indicating whether read was ok and crc matched
- c=<int> current counter value
example from the successful read:
00 02 00 00 00 00 00 00 00 6d 38 00 ff ff 00 00 fe ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2
00 02 00 00 00 00 00 00 00 e0 1f 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2
00 29 c6 5d 18 00 00 00 00 04 37 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=408798761
00 05 00 00 00 00 00 00 00 8d 39 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff crc=YES c=5
example from the read with crc errors:
00 02 00 00 00 00 00 00 00 6d 38 00 ff ff 00 00 fe ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2
00 02 00 00 22 00 00 00 00 e0 1f 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=NO
00 e1 61 5d 19 00 00 00 00 df 0b 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=NO
00 05 00 00 20 00 00 00 00 8d 39 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff crc=NO

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Kernel driver w1_ds28e04
========================
Supported chips:
* Maxim DS28E04-100 4096-Bit Addressable 1-Wire EEPROM with PIO
supported family codes:
W1_FAMILY_DS28E04 0x1C
Author: Markus Franke, <franke.m@sebakmt.com> <franm@hrz.tu-chemnitz.de>
Description
-----------
Support is provided through the sysfs files "eeprom" and "pio". CRC checking
during memory accesses can optionally be enabled/disabled via the device
attribute "crccheck". The strong pull-up can optionally be enabled/disabled
via the module parameter "w1_strong_pullup".
Memory Access
A read operation on the "eeprom" file reads the given amount of bytes
from the EEPROM of the DS28E04.
A write operation on the "eeprom" file writes the given byte sequence
to the EEPROM of the DS28E04. If CRC checking mode is enabled only
fully aligned blocks of 32 bytes with valid CRC16 values (in bytes 30
and 31) are allowed to be written.
PIO Access
The 2 PIOs of the DS28E04-100 are accessible via the "pio" sysfs file.
The current status of the PIO's is returned as an 8 bit value. Bit 0/1
represent the state of PIO_0/PIO_1. Bits 2..7 do not care. The PIO's are
driven low-active, i.e. the driver delivers/expects low-active values.

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Kernel driver w1_therm
====================
Supported chips:
* Maxim ds18*20 based temperature sensors.
* Maxim ds1825 based temperature sensors.
Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Description
-----------
w1_therm provides basic temperature conversion for ds18*20 devices.
supported family codes:
W1_THERM_DS18S20 0x10
W1_THERM_DS1822 0x22
W1_THERM_DS18B20 0x28
W1_THERM_DS1825 0x3B
Support is provided through the sysfs w1_slave file. Each open and
read sequence will initiate a temperature conversion then provide two
lines of ASCII output. The first line contains the nine hex bytes
read along with a calculated crc value and YES or NO if it matched.
If the crc matched the returned values are retained. The second line
displays the retained values along with a temperature in millidegrees
Centigrade after t=.
Parasite powered devices are limited to one slave performing a
temperature conversion at a time. If none of the devices are parasite
powered it would be possible to convert all the devices at the same
time and then go back to read individual sensors. That isn't
currently supported. The driver also doesn't support reduced
precision (which would also reduce the conversion time).
The module parameter strong_pullup can be set to 0 to disable the
strong pullup, 1 to enable autodetection or 2 to force strong pullup.
In case of autodetection, the driver will use the "READ POWER SUPPLY"
command to check if there are pariste powered devices on the bus.
If so, it will activate the master's strong pullup.
In case the detection of parasite devices using this command fails
(seems to be the case with some DS18S20) the strong pullup can
be force-enabled.
If the strong pullup is enabled, the master's strong pullup will be
driven when the conversion is taking place, provided the master driver
does support the strong pullup (or it falls back to a pullup
resistor). The DS18b20 temperature sensor specification lists a
maximum current draw of 1.5mA and that a 5k pullup resistor is not
sufficient. The strong pullup is designed to provide the additional
current required.

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The 1-wire (w1) subsystem
------------------------------------------------------------------
The 1-wire bus is a simple master-slave bus that communicates via a single
signal wire (plus ground, so two wires).
Devices communicate on the bus by pulling the signal to ground via an open
drain output and by sampling the logic level of the signal line.
The w1 subsystem provides the framework for managing w1 masters and
communication with slaves.
All w1 slave devices must be connected to a w1 bus master device.
Example w1 master devices:
DS9490 usb device
W1-over-GPIO
DS2482 (i2c to w1 bridge)
Emulated devices, such as a RS232 converter, parallel port adapter, etc
What does the w1 subsystem do?
------------------------------------------------------------------
When a w1 master driver registers with the w1 subsystem, the following occurs:
- sysfs entries for that w1 master are created
- the w1 bus is periodically searched for new slave devices
When a device is found on the bus, w1 core tries to load the driver for its family
and check if it is loaded. If so, the family driver is attached to the slave.
If there is no driver for the family, default one is assigned, which allows to perform
almost any kind of operations. Each logical operation is a transaction
in nature, which can contain several (two or one) low-level operations.
Let's see how one can read EEPROM context:
1. one must write control buffer, i.e. buffer containing command byte
and two byte address. At this step bus is reset and appropriate device
is selected using either W1_SKIP_ROM or W1_MATCH_ROM command.
Then provided control buffer is being written to the wire.
2. reading. This will issue reading eeprom response.
It is possible that between 1. and 2. w1 master thread will reset bus for searching
and slave device will be even removed, but in this case 0xff will
be read, since no device was selected.
W1 device families
------------------------------------------------------------------
Slave devices are handled by a driver written for a family of w1 devices.
A family driver populates a struct w1_family_ops (see w1_family.h) and
registers with the w1 subsystem.
Current family drivers:
w1_therm - (ds18?20 thermal sensor family driver)
provides temperature reading function which is bound to ->rbin() method
of the above w1_family_ops structure.
w1_smem - driver for simple 64bit memory cell provides ID reading method.
You can call above methods by reading appropriate sysfs files.
What does a w1 master driver need to implement?
------------------------------------------------------------------
The driver for w1 bus master must provide at minimum two functions.
Emulated devices must provide the ability to set the output signal level
(write_bit) and sample the signal level (read_bit).
Devices that support the 1-wire natively must provide the ability to write and
sample a bit (touch_bit) and reset the bus (reset_bus).
Most hardware provides higher-level functions that offload w1 handling.
See struct w1_bus_master definition in w1.h for details.
w1 master sysfs interface
------------------------------------------------------------------
<xx-xxxxxxxxxxxxx> - a directory for a found device. The format is family-serial
bus - (standard) symlink to the w1 bus
driver - (standard) symlink to the w1 driver
w1_master_add - Manually register a slave device
w1_master_attempts - the number of times a search was attempted
w1_master_max_slave_count
- maximum number of slaves to search for at a time
w1_master_name - the name of the device (w1_bus_masterX)
w1_master_pullup - 5V strong pullup 0 enabled, 1 disabled
w1_master_remove - Manually remove a slave device
w1_master_search - the number of searches left to do, -1=continual (default)
w1_master_slave_count
- the number of slaves found
w1_master_slaves - the names of the slaves, one per line
w1_master_timeout - the delay in seconds between searches
If you have a w1 bus that never changes (you don't add or remove devices),
you can set the module parameter search_count to a small positive number
for an initially small number of bus searches. Alternatively it could be
set to zero, then manually add the slave device serial numbers by
w1_master_add device file. The w1_master_add and w1_master_remove files
generally only make sense when searching is disabled, as a search will
redetect manually removed devices that are present and timeout manually
added devices that aren't on the bus.
w1 slave sysfs interface
------------------------------------------------------------------
bus - (standard) symlink to the w1 bus
driver - (standard) symlink to the w1 driver
name - the device name, usually the same as the directory name
w1_slave - (optional) a binary file whose meaning depends on the
family driver
rw - (optional) created for slave devices which do not have
appropriate family driver. Allows to read/write binary data.

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Userspace communication protocol over connector [1].
Message types.
=============
There are three types of messages between w1 core and userspace:
1. Events. They are generated each time a new master or slave device
is found either due to automatic or requested search.
2. Userspace commands.
3. Replies to userspace commands.
Protocol.
========
[struct cn_msg] - connector header.
Its length field is equal to size of the attached data
[struct w1_netlink_msg] - w1 netlink header.
__u8 type - message type.
W1_LIST_MASTERS
list current bus masters
W1_SLAVE_ADD/W1_SLAVE_REMOVE
slave add/remove events
W1_MASTER_ADD/W1_MASTER_REMOVE
master add/remove events
W1_MASTER_CMD
userspace command for bus master
device (search/alarm search)
W1_SLAVE_CMD
userspace command for slave device
(read/write/touch)
__u8 status - error indication from kernel
__u16 len - size of data attached to this header data
union {
__u8 id[8]; - slave unique device id
struct w1_mst {
__u32 id; - master's id
__u32 res; - reserved
} mst;
} id;
[struct w1_netlink_cmd] - command for given master or slave device.
__u8 cmd - command opcode.
W1_CMD_READ - read command
W1_CMD_WRITE - write command
W1_CMD_SEARCH - search command
W1_CMD_ALARM_SEARCH - alarm search command
W1_CMD_TOUCH - touch command
(write and sample data back to userspace)
W1_CMD_RESET - send bus reset
W1_CMD_SLAVE_ADD - add slave to kernel list
W1_CMD_SLAVE_REMOVE - remove slave from kernel list
W1_CMD_LIST_SLAVES - get slaves list from kernel
__u8 res - reserved
__u16 len - length of data for this command
For read command data must be allocated like for write command
__u8 data[0] - data for this command
Each connector message can include one or more w1_netlink_msg with
zero or more attached w1_netlink_cmd messages.
For event messages there are no w1_netlink_cmd embedded structures,
only connector header and w1_netlink_msg strucutre with "len" field
being zero and filled type (one of event types) and id:
either 8 bytes of slave unique id in host order,
or master's id, which is assigned to bus master device
when it is added to w1 core.
Currently replies to userspace commands are only generated for read
command request. One reply is generated exactly for one w1_netlink_cmd
read request. Replies are not combined when sent - i.e. typical reply
messages looks like the following:
[cn_msg][w1_netlink_msg][w1_netlink_cmd]
cn_msg.len = sizeof(struct w1_netlink_msg) +
sizeof(struct w1_netlink_cmd) +
cmd->len;
w1_netlink_msg.len = sizeof(struct w1_netlink_cmd) + cmd->len;
w1_netlink_cmd.len = cmd->len;
Replies to W1_LIST_MASTERS should send a message back to the userspace
which will contain list of all registered master ids in the following
format:
cn_msg (CN_W1_IDX.CN_W1_VAL as id, len is equal to sizeof(struct
w1_netlink_msg) plus number of masters multiplied by 4)
w1_netlink_msg (type: W1_LIST_MASTERS, len is equal to
number of masters multiplied by 4 (u32 size))
id0 ... idN
Each message is at most 4k in size, so if number of master devices
exceeds this, it will be split into several messages.
W1 search and alarm search commands.
request:
[cn_msg]
[w1_netlink_msg type = W1_MASTER_CMD
id is equal to the bus master id to use for searching]
[w1_netlink_cmd cmd = W1_CMD_SEARCH or W1_CMD_ALARM_SEARCH]
reply:
[cn_msg, ack = 1 and increasing, 0 means the last message,
seq is equal to the request seq]
[w1_netlink_msg type = W1_MASTER_CMD]
[w1_netlink_cmd cmd = W1_CMD_SEARCH or W1_CMD_ALARM_SEARCH
len is equal to number of IDs multiplied by 8]
[64bit-id0 ... 64bit-idN]
Length in each header corresponds to the size of the data behind it, so
w1_netlink_cmd->len = N * 8; where N is number of IDs in this message.
Can be zero.
w1_netlink_msg->len = sizeof(struct w1_netlink_cmd) + N * 8;
cn_msg->len = sizeof(struct w1_netlink_msg) +
sizeof(struct w1_netlink_cmd) +
N*8;
W1 reset command.
[cn_msg]
[w1_netlink_msg type = W1_MASTER_CMD
id is equal to the bus master id to use for searching]
[w1_netlink_cmd cmd = W1_CMD_RESET]
Command status replies.
======================
Each command (either root, master or slave with or without w1_netlink_cmd
structure) will be 'acked' by the w1 core. Format of the reply is the same
as request message except that length parameters do not account for data
requested by the user, i.e. read/write/touch IO requests will not contain
data, so w1_netlink_cmd.len will be 0, w1_netlink_msg.len will be size
of the w1_netlink_cmd structure and cn_msg.len will be equal to the sum
of the sizeof(struct w1_netlink_msg) and sizeof(struct w1_netlink_cmd).
If reply is generated for master or root command (which do not have
w1_netlink_cmd attached), reply will contain only cn_msg and w1_netlink_msg
structures.
w1_netlink_msg.status field will carry positive error value
(EINVAL for example) or zero in case of success.
All other fields in every structure will mirror the same parameters in the
request message (except lengths as described above).
Status reply is generated for every w1_netlink_cmd embedded in the
w1_netlink_msg, if there are no w1_netlink_cmd structures,
reply will be generated for the w1_netlink_msg.
All w1_netlink_cmd command structures are handled in every w1_netlink_msg,
even if there were errors, only length mismatch interrupts message processing.
Operation steps in w1 core when new command is received.
=======================================================
When new message (w1_netlink_msg) is received w1 core detects if it is
master or slave request, according to w1_netlink_msg.type field.
Then master or slave device is searched for.
When found, master device (requested or those one on where slave device
is found) is locked. If slave command is requested, then reset/select
procedure is started to select given device.
Then all requested in w1_netlink_msg operations are performed one by one.
If command requires reply (like read command) it is sent on command completion.
When all commands (w1_netlink_cmd) are processed master device is unlocked
and next w1_netlink_msg header processing started.
Connector [1] specific documentation.
====================================
Each connector message includes two u32 fields as "address".
w1 uses CN_W1_IDX and CN_W1_VAL defined in include/linux/connector.h header.
Each message also includes sequence and acknowledge numbers.
Sequence number for event messages is appropriate bus master sequence number
increased with each event message sent "through" this master.
Sequence number for userspace requests is set by userspace application.
Sequence number for reply is the same as was in request, and
acknowledge number is set to seq+1.
Additional documantion, source code examples.
============================================
1. Documentation/connector
2. http://www.ioremap.net/archive/w1
This archive includes userspace application w1d.c which uses
read/write/search commands for all master/slave devices found on the bus.