NAME

     own, own_send_command, own_commmand_wait, own_self_command, own_acquire_bus, own crc,
     own_release_bus, OWN_ACQUIRE_BUS, OWN_CRC, OWN_RELEASE_BUS, OWN_SEND_COMMAND — Dallas
     Semiconductor 1-Wire Network and Transport Interface

SYNOPSIS

     #include <sys/bus.h>
     #include <dev/ow/own.h>

     int
     own_send_command(device_t pdev, struct ow_cmd *cmd);

     int
     own_command_wait(device_t pdev, struct ow_cmd *cmd);

     int
     own_self_command(device_t pdev, struct ow_cmd *cmd, uint8_t xpt_cmd);

     int
     own_acquire_bus(device_t pdev, int how);

     int
     own_release_bus(device_t pdev);

     int
     own_crc(device_t pdev, uint8_t *buffer, size_t len);

     int
     OWN_SEND_COMMAND(device_t ndev, device_t pdev, struct ow_cmd *cmd);

     int
     OWN_ACQUIRE_BUS(device_t ndev, device_t pdev, int how);

     void
     OWN_RELEASE_BUS(device_t ndev, device_t pdev);

     uint8_t
     OWN_CRC(device_t ndev, device_t pdev, uint8_t *buffer, size_t len);

DESCRIPTION

     The own interface defines three sets of functions for interacting with 1-Wire devices:
     sending commands, reserving the bus, and ensuring data integrity.  Wrappers are provided for
     the raw OWN kobj(9) interfaces and should be used for improved safety over the kobj(9) ones.

   Bus Commands
     The 1-Wire bus defines different layers of access to the devices on the bus.  The own
     functions provide access to the network and transport layers.  The network layer designates
     the next command as being either for all devices on the bus, or for a specific device.  The
     network layer also specifies the speed used by the link layer.

     struct ow_cmd encapsulates network access, speed, and timing information.  It specifies the
     commands to send and whether or not to read data.  Its members are:

     flags
           Flags controlling the interpretation of the structure.  These flags are defined in
           <dev/ow/ow.h>:

           OW_FLAG_OVERDRIVE
                   Send xpt_cmd bytes and read xpt_read bytes at overdrive speed.

           OW_FLAG_READ_BIT
                   Interpret xpt_read_len to be in bits to be read after xpt_cmd rather than
                   bytes.

     rom_cmd
           ROM command bytes to send.

     rom_len
           Number of ROM command bytes to send.

     rom_read_len
           Number of bytes to read after sending the ROM command.

     rom_read
           Buffer for bytes read after the ROM command.

     xpt_cmd
           Transport command to send.

     xpt_len
           Length of the transport command bytes to send.  Specify 0 for no transport command.

     xpt_read_len
           Number of bytes to read after xpt_cmd bytes are sent.  If the OW_FLAG_READ_BIT bit is
           set in flags, then it is the number of bits to read.  Bits read are packed into bytes.

     xpt_read
           Buffer for data read.

     own_command_wait() acquires the 1-Wire bus, waiting if necessary, sends the command, and
     then releases the bus.  own_send_command() sends the command without bus reservation.  pdev
     is the client device (the presentation layer device) sending the command.  The cmd argument
     describes the transaction to send to the 1-Wire bus.

     own_self_command() fills in cmd with a MATCH_ROM ROM command, the ROM address of pdev and
     the xpt_cmd as a convenient way to create directed commands.

   Bus Reservation
     The 1-Wire system includes an advisory lock for the bus that presentation layer devices can
     use to coordinate access.  Locking is purely advisory at this time.

     own_acquire_bus() reserves the bus.  It waits indefinitely if the how argument is OWN_WAIT
     and returns the error EWOULDBLOCK if passed OWN_DONTWAIT when the bus is owned by another
     client.

     own_release_bus() releases the bus.

   Data Integrity
     own_crc() computes the 1-Wire standard CRC function over the data passed in buffer and len
     and returns the result.

   Notes
     The 1-Wire standard (Maxim AN937) defines layers that are akin to ISO networking layers.
     The lowest relevant layer, the link layer, defines the polling windows and the timing of the
     signaling of different modes.  The network layer is built on top of the link layer and is
     used to address devices in a unicast or multicast manner.  The transport layer defines
     commands and responses from the devices.  The presentation layer is composed of the device
     specific commands and actions used to control the specific 1-Wire devices on bus.

     These interfaces are implemented by the ow(4) device.  Presentation layer devices (children
     of the newbus ow(4) device) should only call the functions described here.  The
     functionality provided by the owc(4) device (specifically the owll(9) interface) should only
     be called by the ow(4) driver.

SEE ALSO

     ow(4), owc(4), owll(9) https://pdfserv.maximintegrated.com/en/an/AN937.pdf

LEGAL

     1-Wire is a registered trademark of Maxim Integrated Products, Inc.

HISTORY

     The own driver first appeared in FreeBSD 11.0.

AUTHORS

     The own device driver and this manual page were written by Warner Losh.