mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-25 04:23:46 +00:00
200 lines
7 KiB
C
200 lines
7 KiB
C
/*
|
|
* (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_
|
|
|
|
/* Controller-specific definitions: */
|
|
|
|
/* CONFIG_HARD_SPI triggers SPI bus initialization in PowerPC */
|
|
#ifdef CONFIG_MPC8XXX_SPI
|
|
# ifndef CONFIG_HARD_SPI
|
|
# define CONFIG_HARD_SPI
|
|
# endif
|
|
#endif
|
|
|
|
/* 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 */
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* 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.
|
|
*/
|
|
struct spi_slave {
|
|
unsigned int bus;
|
|
unsigned int cs;
|
|
};
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* Initialization, must be called once on start up.
|
|
*
|
|
* TODO: I don't think we really need this.
|
|
*/
|
|
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);
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* Free any memory associated with a SPI slave.
|
|
*
|
|
* slave: The SPI slave
|
|
*/
|
|
void spi_free_slave(struct spi_slave *slave);
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* 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.
|
|
* bitlen: How many bits to write and read.
|
|
* dout: Pointer to a string of bits to send out. The bits are
|
|
* held in a byte array and are sent MSB first.
|
|
* din: Pointer to a string of bits that will be filled in.
|
|
* flags: A bitwise combination of SPI_XFER_* flags.
|
|
*
|
|
* Returns: 0 on success, not 0 on failure
|
|
*/
|
|
int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
|
|
void *din, unsigned long flags);
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* 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);
|
|
|
|
/*-----------------------------------------------------------------------
|
|
* 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, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
|
|
return ret < 0 ? ret : din[1];
|
|
}
|
|
|
|
#endif /* _SPI_H_ */
|