The zephyr-serial w1 driver introduced in this commit implements
all routines for the w1 api on top of the zephyr serial driver.
W1 bit read, write, and reset operations are executed by issuing
polling zephyr serial byte read and write operations.
The driver should be usable on most platforms in zephyr that have
implemented support for the polling procedures of the serial driver.
As not all serial drivers are implemented exactly the same minor
additional quirks may be needed on some platforms.
The most notable difference of polling serial driver implementations
seems to be that some return immediately from poll_out after the
transmission was started(e.g. STM32) and others wait until
the transmission was completed before returning from poll_out
(e.g. NRF). While this has influence on the timeout, both types
are supported by this driver because the driver waits for a
configurable time period until it terminates the read.
The driver needs an appropriate open drain interface to be able
to communicate with slaves.
In the simpliest case this might be achived by configuring the mcu pins
in open-drain configuration with a (sufficiently small) pull-up to 3V3/5V.
Otherwise an external circuit needs to provide this interface.
Overdrive and Standard Speed modes are supported by this driver.
Signed-off-by: Thomas Stranger <thomas.stranger@outlook.com>
This commit introduces a new api for the net layer of Dallas
1-wire protocol.
For single drop configurations w1_read_rom, and w1_skip_rom commands are
provided.
For multidrop configurations w1_match_rom, w1_resume_command,
w1_search_rom, and w1_search_alarm routines are provided as well.
Additionally, the reset_select routine, conditionally depending on the
bus configuration, either executes a match_rom, or a skip rom command.
A w1_write_read command simplifies the typical scenario of addressing
a device, writing a few bytes to the device and reading back the answer.
Additionally w1_crc8, and w1_crc16 are added as wrappers around the
zephyr in-tree crc8 and crc16_reflect implementations.
The former may be used to verify the validity of the rom id, while the
latter is used for integrity checking of many eeprom, and authenticator
commands.
The general search command does not support filtering on
the family code.
Signed-off-by: Thomas Stranger <thomas.stranger@outlook.com>
This commit introduces a new api for the Dallas 1-wire protocol.
The api includes link functions for read and write operations on
bit, byte, and block level, as well as functions to reset and
lock the bus.
The bus configuration is derived from the device tree and can be
queried using w1_slave_count routine.
Signed-off-by: Thomas Stranger <thomas.stranger@outlook.com>
Thomas Stranger