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microchip,mcp23s17 (on spi bus)

Vendor: Microchip Technology Inc.

Description

This is a representation of the Microchip MCP23S17 SPI Gpio Expander.

Properties

Top level properties

These property descriptions apply to “microchip,mcp23s17” nodes themselves. This page also describes child node properties in the following sections.

Properties not inherited from the base binding file.

Name

Type

Details

#gpio-cells

int

Number of items to expect in a GPIO specifier

This property is required.

Constant value: 2

ngpios

int

Number of gpios supported

This property is required.

Default value: 32

Constant value: 16

gpio-controller

boolean

Convey's this node is a GPIO controller

This property is required.

gpio-reserved-ranges

array

If not all the GPIOs at offsets 0...N-1 are usable for ngpios = <N>, then
this property contains an additional set of tuples which specify which GPIOs
are unusable. This property indicates the start and size of the GPIOs
that can't be used.

For example, setting "gpio-reserved-ranges = <3 2>, <10 1>;" means that
GPIO offsets 3, 4, and 10 are not usable, even if ngpios = <18>.

gpio-line-names

string-array

This is an array of strings defining the names of the GPIO lines
going out of the GPIO controller

spi-max-frequency

int

Maximum clock frequency of device's SPI interface in Hz

This property is required.

duplex

int

Duplex mode, full or half. By default it's always full duplex thus 0
as this is, by far, the most common mode.
Use the macros not the actual enum value, here is the concordance
list (see dt-bindings/spi/spi.h)
  0    SPI_FULL_DUPLEX
  2048 SPI_HALF_DUPLEX

Legal values: 0, 2048

frame-format

int

Motorola or TI frame format. By default it's always Motorola's,
thus 0 as this is, by far, the most common format.
Use the macros not the actual enum value, here is the concordance
list (see dt-bindings/spi/spi.h)
  0     SPI_FRAME_FORMAT_MOTOROLA
  32768 SPI_FRAME_FORMAT_TI

Legal values: 0, 32768

spi-cpol

boolean

SPI clock polarity which indicates the clock idle state.
If it is used, the clock idle state is logic high; otherwise, low.

spi-cpha

boolean

SPI clock phase that indicates on which edge data is sampled.
If it is used, data is sampled on the second edge; otherwise, on the first edge.

spi-hold-cs

boolean

In some cases, it is necessary for the master to manage SPI chip select
under software control, so that multiple spi transactions can be performed
without releasing it. A typical use case is variable length SPI packets
where the first spi transaction reads the length and the second spi transaction
reads length bytes.

supply-gpios

phandle-array

GPIO specifier that controls power to the device.

This property should be provided when the device has a dedicated
switch that controls power to the device.  The supply state is
entirely the responsibility of the device driver.

Contrast with vin-supply.

vin-supply

phandle

Reference to the regulator that controls power to the device.
The referenced devicetree node must have a regulator compatible.

This property should be provided when device power is supplied
by a shared regulator.  The supply state is dependent on the
request status of all devices fed by the regulator.

Contrast with supply-gpios.  If both properties are provided
then the regulator must be requested before the supply GPIOS is
set to an active state, and the supply GPIOS must be set to an
inactive state before releasing the regulator.

Child node properties

Name

Type

Details

gpio-hog

boolean

Conveys this node is a GPIO hog.

This property is required.

gpios

array

This is an array of GPIO specifiers (e.g. pin, flags) to be hogged. The number of array
entries must be an integer multiple of the number of GPIO specifier cells for the parent
GPIO controller.

This property is required.

input

boolean

If this property is set, the GPIO is configured as an input. This property takes
precedence over the output-low and output-high properties.

output-low

boolean

If this property is set, the GPIO is configured as an output set to logical low. This
property takes precedence over the output-high property.

output-high

boolean

If this property is set, the GPIO is configured as an output set to logical high.

line-name

string

Optional GPIO line name.

Specifier cell names

  • gpio cells: pin, flags