bsps/xilinx_zynq: Add SPI driver for cadence-spi

Updates #4320

bsps/include/dev/spi/cadence-spi.h

@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/*
+ * Copyright (C) 2021 Jan Sommer, German Aerospace Center (DLR)
+ *
+ * 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.
+ *
+ * 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 OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED 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.
+ */
+
+#ifndef LIBBSP_ARM_XILINX_ZYNQ_CADENCE_SPI_H
+#define LIBBSP_ARM_XILINX_ZYNQ_CADENCE_SPI_H
+
+#include <rtems.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/**
+ * Register the cadence-spi device with rtems
+ *
+ * @param bus_path path of the new device (e.g. /dev/spi0)
+ * @register_base Address of the first (i.e. config) register
+ * @input_clock Configured frequency of the input clock
+ *
+ * @return RTEMS_SUCCESSFUL on success, negative number on failure
+ *
+ * Note: The spi frequencies the cadence spi device can achieve
+ *       are the @p input_clock divided by a power of 2 between
+ *       4 and 256.
+ *       The driver tries to find a divider which yields a spi
+ *       frequency equal to or lower than the desired bus frequency.
+ */
+int spi_bus_register_cadence(
+  const char *bus_path,
+  uintptr_t register_base,
+  uint32_t input_clock,
+  rtems_vector_number irq
+);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* LIBBSP_ARM_XILINX_ZYNQ_CADENCE_SPI_H */