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34 .Nd driver for PCA9548A I2C switch
36 To compile this driver into the kernel,
37 place the following line in your
38 kernel configuration file:
39 .Bd -ragged -offset indent
45 Alternatively, to load the driver as a
46 module at boot time, place the following line in
48 .Bd -literal -offset indent
54 driver supports the PCA9548A I2C bus switch and compatible chips such as
56 It automatically connects an upstream I2C bus to one of several downstream
57 buses as needed when slave devices on the downstream buses initiate I/O.
58 More information on the automatic switching behavior is available in
65 device node is defined as a child node of its upstream I2C bus.
68 node are additional I2C buses, which will have their own I2C slave
69 devices described in their child nodes.
73 driver attaches to nodes where the
75 property is set to one of
83 driver supports the following optional properties in addition to the standard
85 .Bl -tag -width i2c-mux-idle-disconnect
86 .It Va i2c-mux-idle-disconnect
87 if defined, forces the switch to disconnect all children in idle state.
89 .Sh HINTS CONFIGURATION
92 based system, these values are configurable for
94 .Bl -tag -width hint.pca954x.<unit>.chip_type
95 .It Va hint.pca954x.<unit>.at
100 instance is attached to.
101 .It Va hint.pca954x.<unit>.chip_type
102 The type of the chip.
108 When configured via hints, the driver automatically adds an
110 instance for every downstream bus supported by the chip.
111 There is currently no way to indicate used versus unused channels.
118 driver and this manual page was written by
119 .An Andriy Gapon Aq Mt avg@FreeBSD.org .