/****************************************************************************
*
* Copyright (C) 2012 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file spi.h
*
* Base class for devices connected via SPI.
*/
#ifndef _DEVICE_SPI_H
#define _DEVICE_SPI_H
#include "device.h"
#include <nuttx/spi.h>
namespace device __EXPORT
{
/**
* Abstract class for character device on SPI
*/
class __EXPORT SPI : public CDev
{
protected:
/**
* Constructor
*
* @param name Driver name
* @param devname Device node name
* @param bus SPI bus on which the device lives
* @param device Device handle (used by SPI_SELECT)
* @param mode SPI clock/data mode
* @param frequency SPI clock frequency
* @param irq Interrupt assigned to the device (or zero if none)
*/
SPI(const char *name,
const char *devname,
int bus,
enum spi_dev_e device,
enum spi_mode_e mode,
uint32_t frequency,
int irq = 0);
virtual ~SPI();
virtual int init();
/**
* Check for the presence of the device on the bus.
*/
virtual int probe();
/**
* Perform a SPI transfer.
*
* If called from interrupt context, this interface does not lock
* the bus and may interfere with non-interrupt-context callers.
*
* Clients in a mixed interrupt/non-interrupt configuration must
* ensure appropriate interlocking.
*
* At least one of send or recv must be non-null.
*
* @param send Bytes to send to the device, or nullptr if
* no data is to be sent.
* @param recv Buffer for receiving bytes from the device,
* or nullptr if no bytes are to be received.
* @param len Number of bytes to transfer.
* @return OK if the exchange was successful, -errno
* otherwise.
*/
int transfer(uint8_t *send, uint8_t *recv, unsigned len);
/**
* Set the SPI bus frequency
* This is used to change frequency on the fly. Some sensors
* (such as the MPU6000) need a lower frequency for setup
* registers and can handle higher frequency for sensor
* value registers
*
* @param frequency Frequency to set (Hz)
*/
void set_frequency(uint32_t frequency);
/**
* Locking modes supported by the driver.
*/
enum LockMode {
LOCK_PREEMPTION, /**< the default; lock against all forms of preemption. */
LOCK_THREADS, /**< lock only against other threads, using SPI_LOCK */
LOCK_NONE /**< perform no locking, only safe if the bus is entirely private */
};
LockMode locking_mode; /**< selected locking mode */
private:
int _bus;
enum spi_dev_e _device;
enum spi_mode_e _mode;
uint32_t _frequency;
struct spi_dev_s *_dev;
int _transfer(uint8_t *send, uint8_t *recv, unsigned len);
};
} // namespace device
#endif /* _DEVICE_SPI_H */
