Add SPI-MEM framework
This framework supports SPI operations using a common
spi_mem_op structure:
- command
- addr
- dummy
- data
The framework manages SPI bus configuration:
- speed
- bus width (Up to quad mode)
- chip select
Change-Id: Idc2736c59bfc5ac6e55429eba5d385275ea3fbde
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Christophe Kerello <christophe.kerello@st.com>
diff --git a/include/drivers/spi_mem.h b/include/drivers/spi_mem.h
new file mode 100644
index 0000000..d1953ac
--- /dev/null
+++ b/include/drivers/spi_mem.h
@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2019, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef DRIVERS_SPI_MEM_H
+#define DRIVERS_SPI_MEM_H
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#define SPI_MEM_BUSWIDTH_1_LINE 1U
+#define SPI_MEM_BUSWIDTH_2_LINE 2U
+#define SPI_MEM_BUSWIDTH_4_LINE 4U
+
+/*
+ * enum spi_mem_data_dir - Describes the direction of a SPI memory data
+ * transfer from the controller perspective.
+ * @SPI_MEM_DATA_IN: data coming from the SPI memory.
+ * @SPI_MEM_DATA_OUT: data sent to the SPI memory.
+ */
+enum spi_mem_data_dir {
+ SPI_MEM_DATA_IN,
+ SPI_MEM_DATA_OUT,
+};
+
+/*
+ * struct spi_mem_op - Describes a SPI memory operation.
+ *
+ * @cmd.buswidth: Number of IO lines used to transmit the command.
+ * @cmd.opcode: Operation opcode.
+ * @addr.nbytes: Number of address bytes to send. Can be zero if the operation
+ * does not need to send an address.
+ * @addr.buswidth: Number of IO lines used to transmit the address.
+ * @addr.val: Address value. This value is always sent MSB first on the bus.
+ * Note that only @addr.nbytes are taken into account in this
+ * address value, so users should make sure the value fits in the
+ * assigned number of bytes.
+ * @dummy.nbytes: Number of dummy bytes to send after an opcode or address. Can
+ * be zero if the operation does not require dummy bytes.
+ * @dummy.buswidth: Number of IO lines used to transmit the dummy bytes.
+ * @data.buswidth: Number of IO lines used to send/receive the data.
+ * @data.dir: Direction of the transfer.
+ * @data.nbytes: Number of data bytes to transfer.
+ * @data.buf: Input or output data buffer depending on data::dir.
+ */
+struct spi_mem_op {
+ struct {
+ uint8_t buswidth;
+ uint8_t opcode;
+ } cmd;
+
+ struct {
+ uint8_t nbytes;
+ uint8_t buswidth;
+ uint64_t val;
+ } addr;
+
+ struct {
+ uint8_t nbytes;
+ uint8_t buswidth;
+ } dummy;
+
+ struct {
+ uint8_t buswidth;
+ enum spi_mem_data_dir dir;
+ unsigned int nbytes;
+ void *buf;
+ } data;
+};
+
+/* SPI mode flags */
+#define SPI_CPHA BIT(0) /* clock phase */
+#define SPI_CPOL BIT(1) /* clock polarity */
+#define SPI_CS_HIGH BIT(2) /* CS active high */
+#define SPI_LSB_FIRST BIT(3) /* per-word bits-on-wire */
+#define SPI_3WIRE BIT(4) /* SI/SO signals shared */
+#define SPI_PREAMBLE BIT(5) /* Skip preamble bytes */
+#define SPI_TX_DUAL BIT(6) /* transmit with 2 wires */
+#define SPI_TX_QUAD BIT(7) /* transmit with 4 wires */
+#define SPI_RX_DUAL BIT(8) /* receive with 2 wires */
+#define SPI_RX_QUAD BIT(9) /* receive with 4 wires */
+
+struct spi_bus_ops {
+ /*
+ * Claim the bus and prepare it for communication.
+ *
+ * @cs: The chip select.
+ * Returns: 0 if the bus was claimed successfully, or a negative value
+ * if it wasn't.
+ */
+ int (*claim_bus)(unsigned int cs);
+
+ /*
+ * Release the SPI bus.
+ */
+ void (*release_bus)(void);
+
+ /*
+ * Set transfer speed.
+ *
+ * @hz: The transfer speed in Hertz.
+ * Returns: 0 on success, a negative error code otherwise.
+ */
+ int (*set_speed)(unsigned int hz);
+
+ /*
+ * Set the SPI mode/flags.
+ *
+ * @mode: Requested SPI mode (SPI_... flags).
+ * Returns: 0 on success, a negative error code otherwise.
+ */
+ int (*set_mode)(unsigned int mode);
+
+ /*
+ * Execute a SPI memory operation.
+ *
+ * @op: The memory operation to execute.
+ * Returns: 0 on success, a negative error code otherwise.
+ */
+ int (*exec_op)(const struct spi_mem_op *op);
+};
+
+int spi_mem_exec_op(const struct spi_mem_op *op);
+int spi_mem_init_slave(void *fdt, int bus_node,
+ const struct spi_bus_ops *ops);
+
+#endif /* DRIVERS_SPI_MEM_H */