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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package driver contains interfaces to be implemented by various SPI implementations.
package driver // import "golang.org/x/exp/io/spi/driver"
const (
Mode = iota
Bits
MaxSpeed
Order
Delay
CSChange
)
// Opener is an interface to be implemented by the SPI driver to open
// a connection to an SPI device.
type Opener interface {
Open() (Conn, error)
}
// Conn is a connection to an SPI device.
// TODO(jbd): Extend the interface to query configuration values.
type Conn interface {
// Configure configures the SPI device.
//
// Available configuration keys are:
// - Mode, the SPI mode (valid values are 0, 1, 2 and 3).
// - Bits, bits per word (default is 8-bit per word).
// - Speed, the max clock speed (in Hz).
// - Order, bit order to be used in transfers. Zero value represents
// the MSB-first, non-zero values represent LSB-first encoding.
// - Delay, the pause time between frames (in usecs).
// Some SPI devices require a minimum amount of wait time after
// each frame write. If set, Delay amount of usecs are inserted after
// each write.
// - CSChange, whether to leave the device's chipselect active after a Tx.
//
// SPI devices can override these values.
Configure(k, v int) error
// Tx performs a SPI transaction: w is written if not nil, the result is
// put into r if not nil. len(w) must be equal to len(r), otherwise the
// driver should return an error.
Tx(w, r []byte) error
// Close frees the underlying resources and closes the connection.
Close() error
}
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