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+/*
+ * (C) Copyright 2001
+ * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _SPI_H_
+#define _SPI_H_
+
+#include <stdint.h>
+
+/* Controller-specific definitions: */
+
+/* SPI mode flags */
+#define SPI_CPHA 0x01 /* clock phase */
+#define SPI_CPOL 0x02 /* clock polarity */
+#define SPI_MODE_0 (0|0) /* (original MicroWire) */
+#define SPI_MODE_1 (0|SPI_CPHA)
+#define SPI_MODE_2 (SPI_CPOL|0)
+#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
+#define SPI_CS_HIGH 0x04 /* CS active high */
+#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
+#define SPI_3WIRE 0x10 /* SI/SO signals shared */
+#define SPI_LOOP 0x20 /* loopback mode */
+
+/* SPI transfer flags */
+#define SPI_XFER_BEGIN 0x01 /* Assert CS before transfer */
+#define SPI_XFER_END 0x02 /* Deassert CS after transfer */
+
+/* SPI opcodes */
+#define SPI_OPCODE_WREN 0x06
+#define SPI_OPCODE_FAST_READ 0x0b
+
+#define SPI_READ_FLAG 0x01
+#define SPI_WRITE_FLAG 0x02
+
+/*-----------------------------------------------------------------------
+ * Representation of a SPI slave, i.e. what we're communicating with.
+ *
+ * Drivers are expected to extend this with controller-specific data.
+ *
+ * bus: ID of the bus that the slave is attached to.
+ * cs: ID of the chip select connected to the slave.
+ * rw: Read or Write flag
+ */
+struct spi_slave {
+ unsigned int bus;
+ unsigned int cs;
+ unsigned int rw;
+};
+
+/*-----------------------------------------------------------------------
+ * Initialization, must be called once on start up.
+ *
+ */
+void spi_init(void);
+
+/*-----------------------------------------------------------------------
+ * Set up communications parameters for a SPI slave.
+ *
+ * This must be called once for each slave. Note that this function
+ * usually doesn't touch any actual hardware, it only initializes the
+ * contents of spi_slave so that the hardware can be easily
+ * initialized later.
+ *
+ * bus: Bus ID of the slave chip.
+ * cs: Chip select ID of the slave chip on the specified bus.
+ * max_hz: Maximum SCK rate in Hz.
+ * mode: Clock polarity, clock phase and other parameters.
+ *
+ * Returns: A spi_slave reference that can be used in subsequent SPI
+ * calls, or NULL if one or more of the parameters are not supported.
+ */
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+ unsigned int max_hz, unsigned int mode);
+
+/*-----------------------------------------------------------------------
+ * Claim the bus and prepare it for communication with a given slave.
+ *
+ * This must be called before doing any transfers with a SPI slave. It
+ * will enable and initialize any SPI hardware as necessary, and make
+ * sure that the SCK line is in the correct idle state. It is not
+ * allowed to claim the same bus for several slaves without releasing
+ * the bus in between.
+ *
+ * slave: The SPI slave
+ *
+ * Returns: 0 if the bus was claimed successfully, or a negative value
+ * if it wasn't.
+ */
+int spi_claim_bus(struct spi_slave *slave);
+
+/*-----------------------------------------------------------------------
+ * Release the SPI bus
+ *
+ * This must be called once for every call to spi_claim_bus() after
+ * all transfers have finished. It may disable any SPI hardware as
+ * appropriate.
+ *
+ * slave: The SPI slave
+ */
+void spi_release_bus(struct spi_slave *slave);
+
+/*-----------------------------------------------------------------------
+ * SPI transfer
+ *
+ * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
+ * "bitlen" bits in the SPI MISO port. That's just the way SPI works.
+ *
+ * The source of the outgoing bits is the "dout" parameter and the
+ * destination of the input bits is the "din" parameter. Note that "dout"
+ * and "din" can point to the same memory location, in which case the
+ * input data overwrites the output data (since both are buffered by
+ * temporary variables, this is OK).
+ *
+ * spi_xfer() interface:
+ * slave: The SPI slave which will be sending/receiving the data.
+ * dout: Pointer to a string of bits to send out. The bits are
+ * held in a byte array and are sent MSB first.
+ * bitsout: How many bits to write.
+ * din: Pointer to a string of bits that will be filled in.
+ * bitsin: How many bits to read.
+ *
+ * Returns: 0 on success, not 0 on failure
+ */
+int spi_xfer(struct spi_slave *slave, const void *dout, unsigned int bitsout,
+ void *din, unsigned int bitsin);
+
+/*-----------------------------------------------------------------------
+ * Determine if a SPI chipselect is valid.
+ * This function is provided by the board if the low-level SPI driver
+ * needs it to determine if a given chipselect is actually valid.
+ *
+ * Returns: 1 if bus:cs identifies a valid chip on this board, 0
+ * otherwise.
+ */
+int spi_cs_is_valid(unsigned int bus, unsigned int cs);
+
+/*-----------------------------------------------------------------------
+ * Activate a SPI chipselect.
+ * This function is provided by the board code when using a driver
+ * that can't control its chipselects automatically (e.g.
+ * common/soft_spi.c). When called, it should activate the chip select
+ * to the device identified by "slave".
+ */
+void spi_cs_activate(struct spi_slave *slave);
+
+/*-----------------------------------------------------------------------
+ * Deactivate a SPI chipselect.
+ * This function is provided by the board code when using a driver
+ * that can't control its chipselects automatically (e.g.
+ * common/soft_spi.c). When called, it should deactivate the chip
+ * select to the device identified by "slave".
+ */
+void spi_cs_deactivate(struct spi_slave *slave);
+
+/*-----------------------------------------------------------------------
+ * Set transfer speed.
+ * This sets a new speed to be applied for next spi_xfer().
+ * slave: The SPI slave
+ * hz: The transfer speed
+ */
+void spi_set_speed(struct spi_slave *slave, uint32_t hz);
+
+/*-----------------------------------------------------------------------
+ * Write 8 bits, then read 8 bits.
+ * slave: The SPI slave we're communicating with
+ * byte: Byte to be written
+ *
+ * Returns: The value that was read, or a negative value on error.
+ *
+ * TODO: This function probably shouldn't be inlined.
+ */
+static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte)
+{
+ unsigned char dout[2];
+ unsigned char din[2];
+ int ret;
+
+ dout[0] = byte;
+ dout[1] = 0;
+
+ ret = spi_xfer(slave, dout, 16, din, 16);
+ return ret < 0 ? ret : din[1];
+}
+
+#endif /* _SPI_H_ */