NAME

       ltc430x — driver for LTC4305 and LTC4306 I2C mux chips

SYNOPSIS

       To compile this driver into the kernel, place the following line in your kernel configuration file:

             device ltc430x

       Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

             ltc430x_load="YES"

DESCRIPTION

       The  ltc430x  driver  supports the LTC4305 and LTC4306 I2C bus multiplexer (mux) chips.  It automatically
       connects an upstream I2C bus to one of several downstream buses as  needed  when  slave  devices  on  the
       downstream  buses  initiate  I/O.   More  information on the automatic switching behavior is available in
       iicmux(4).

FDT CONFIGURATION

       On an fdt(4) based system, an ltc430x device node is defined as a child node of  its  upstream  i2c  bus.
       The  children  of  the ltc430x node are additional i2c buses, which will have their own i2c slave devices
       described in their child nodes.

       The ltc430x driver conforms to the standard i2c/i2c-mux-ltc4306.txt bindings document,  except  that  the
       following optional properties are not currently supported and will be ignored if present:
             •   enable-gpios
             •   gpio-controller
             •   #gpio-cells
             •   ltc,downstream-accelerators-enable
             •   ltc,upstream-accelerators-enable

HINTS CONFIGURATION

       On a device.hints(5) based system, these values are configurable for ltc430x:

       hint.ltc430x.<unit>.at
               The upstream iicbus(4) the ltc430x instance is attached to.

       When  configured  via  hints,  the  driver automatically adds an iicbus instance for every downstream bus
       supported by the chip.  There is currently no way to indicate used versus unused channels.

SEE ALSO

       iicbus(4), iicmux(4),

HISTORY

       The ltc430x driver first appeared in FreeBSD 13.0.

Debian                                           January 1, 2020                                      LTC430X(4)