android-things: Prep for peripheralmanager support

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

include/peripheralmanager/spi_device.h

@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SYSTEM_PERIPHERALMANAGER_SPI_DEVICE_H_
+#define SYSTEM_PERIPHERALMANAGER_SPI_DEVICE_H_
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+__BEGIN_DECLS
+
+/// @defgroup Spi Spi device interface
+/// @brief Functions to control an SPI device.
+///
+/// These functions can be used to control an SPI device.
+/// @{
+
+/// Endianness.
+enum {
+  SPI_LSB_FIRST,  /**< Least significant bits first */
+  SPI_MSB_FIRST  /**< Most significant bits first */
+};
+
+/// SPI phase modes.
+enum {
+  SPI_CPHA = 0x01,  /**< Clock phase */
+  SPI_CPOL = 0x02  /**< Clock polarity */
+};
+
+/// SPI modes (similar to the Linux kernel's modes).
+enum {
+  SPI_MODE0 = 0,  /**< CPHA=0, CPOL=0 */
+  SPI_MODE1 = SPI_CPHA,  /**< CPHA=1, CPOL=0 */
+  SPI_MODE2 = SPI_CPOL,  /**< CPHA=0, CPOL=1 */
+  SPI_MODE3 = SPI_CPHA + SPI_CPOL  /**< CPHA=1, CPOL=1 */
+};
+
+typedef struct BSpiDevice BSpiDevice;
+
+/// Writes a buffer to the device.
+/// @param device Pointer to the BSpiDevice struct.
+/// @param data Buffer to write.
+/// @param len Length of the buffer.
+/// @return 0 on success, errno on error.
+int BSpiDevice_writeBuffer(const BSpiDevice* device,
+                           const void* data,
+                           size_t len);
+
+/// Reads a buffer from the device.
+/// @param device Pointer to the BSpiDevice struct.
+/// @param data Buffer to read into.
+/// @param len Length of the buffer.
+/// @return 0 on success, errno on error.
+int BSpiDevice_readBuffer(const BSpiDevice* device,
+                          void* data,
+                          size_t len);
+
+/// Transfer data to the device.
+/// @param device Pointer to the BSpiDevice struct.
+/// @param tx_data Buffer to write.
+/// @param rx_data Buffer to read data in. If NULL, no data will be read.
+/// @param len Length of the buffers.
+/// @return 0 on success, errno on error.
+int BSpiDevice_transfer(const BSpiDevice* device,
+                        const void* tx_data,
+                        void* rx_data,
+                        size_t len);
+
+/// Sets the frequency in Hertz.
+/// @param device Pointer to the BSpiDevice struct.
+/// @param freq_hz Frequency to set.
+/// @return 0 on success, errno on error.
+int BSpiDevice_setFrequency(const BSpiDevice* device, uint32_t freq_hz);
+
+/// Sets the SPI mode.
+/// @param device Pointer to the BSpiDevice struct.
+/// @param mode Mode to use. One of SPI_MODE0, SPI_MODE1, SPI_MODE2, SPI_MODE3.
+/// @return 0 on success, errno on error.
+int BSpiDevice_setMode(const BSpiDevice* device, int mode);
+
+/// Sets the bit justification.
+/// @param device Pointer to the BSpiDevice struct.
+/// @param bit_justification One of SPI_LSB_FIRST OR SPI_MSB_FIRST.
+/// @return 0 on success, errno on error.
+int BSpiDevice_setBitJustification(const BSpiDevice* device,
+                                   int bit_justification);
+
+/// Sets the number of bits per words.
+/// @param device Pointer to the BSpiDevice struct.
+/// @param bits_per_word Number of bits per word.
+/// @return 0 on success, errno on error.
+int BSpiDevice_setBitsPerWord(const BSpiDevice* device, uint8_t bits_per_word);
+
+/// Sets the delay to wait after each transfer.
+/// @param device Pointer to the BSpiDevice struct.
+/// @param delay_usecs Delay in microseconds.
+/// @return 0 on success, errno on error.
+int BSpiDevice_setDelay(const BSpiDevice* device, uint16_t delay_usecs);
+
+/// Sets the chip select behavior after each transfer.
+/// @param device Pointer to the BSpiDevice struct.
+/// @param change If set, cs will be active between transfers.
+/// @return 0 on success, errno on error.
+int BSpiDevice_setCsChange(const BSpiDevice* device, int change);
+
+/// Destroys a BSpiDevice struct.
+/// @param device Pointer to the BSpiDevice struct.
+void BSpiDevice_delete(BSpiDevice* device);
+
+/// @}
+
+__END_DECLS
+
+#endif  // SYSTEM_PERIPHERALMANAGER_SPI_DEVICE_H_