15797fb67c
1. Use size_t instead of unsigned int for bytes_out and bytes_in. 2. Use const attribute for spi_slave structure passed into xfer, claim bus and release bus functions. BUG=chrome-os-partner:59832 BRANCH=None TEST=Compiles successfully Signed-off-by: Furquan Shaikh <furquan@chromium.org> Reviewed-on: https://review.coreboot.org/17682 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org> Change-Id: Ie70b3520b51c42d750f907892545510c6058f85a Reviewed-on: https://chromium-review.googlesource.com/417079 Commit-Ready: Furquan Shaikh <furquan@chromium.org> Tested-by: Furquan Shaikh <furquan@chromium.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org>
123 lines
4 KiB
C
123 lines
4 KiB
C
/*
|
|
* (C) Copyright 2001
|
|
* Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#ifndef _SPI_GENERIC_H_
|
|
#define _SPI_GENERIC_H_
|
|
|
|
#include <stdint.h>
|
|
#include <stddef.h>
|
|
|
|
/* Controller-specific definitions: */
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* Representation of a SPI slave, i.e. what we're communicating with.
|
|
*
|
|
* bus: ID of the bus that the slave is attached to.
|
|
* cs: ID of the chip select connected to the slave.
|
|
*/
|
|
struct spi_slave {
|
|
unsigned int bus;
|
|
unsigned int cs;
|
|
};
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* 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.
|
|
*
|
|
* 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);
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* 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(const 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(const struct spi_slave *slave);
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* SPI transfer
|
|
*
|
|
* spi_xfer() interface:
|
|
* slave: The SPI slave which will be sending/receiving the data.
|
|
* dout: Pointer to a string of bytes to send out.
|
|
* bytesout: How many bytes to write.
|
|
* din: Pointer to a string of bytes that will be filled in.
|
|
* bytesin: How many bytes to read.
|
|
*
|
|
* Returns: 0 on success, not 0 on failure
|
|
*/
|
|
int spi_xfer(const struct spi_slave *slave, const void *dout, size_t bytesout,
|
|
void *din, size_t bytesin);
|
|
|
|
unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len);
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* 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(const 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, 2, din, 2);
|
|
return ret < 0 ? ret : din[1];
|
|
}
|
|
|
|
#endif /* _SPI_GENERIC_H_ */
|