mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-12 16:07:30 +00:00
59 lines
1.9 KiB
C
59 lines
1.9 KiB
C
|
/*
|
||
|
|
* Simulate a SPI port and clients (see README.sandbox for details)
|
||
|
|
*
|
||
|
|
* Copyright (c) 2011-2013 The Chromium OS Authors.
|
||
|
|
* See file CREDITS for list of people who contributed to this
|
||
|
|
* project.
|
||
|
|
*
|
||
|
|
* Licensed under the GPL-2 or later.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef __ASM_SPI_H__
|
||
|
|
#define __ASM_SPI_H__
|
||
|
|
|
||
|
|
#include <linux/types.h>
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The interface between the SPI bus and the SPI client. The bus will
|
||
|
|
* instantiate a client, and that then call into it via these entry
|
||
|
|
* points. These should be enough for the client to emulate the SPI
|
||
|
|
* device just like the real hardware.
|
||
|
|
*/
|
||
|
|
struct sandbox_spi_emu_ops {
|
||
|
|
/* The bus wants to instantiate a new client, so setup everything */
|
||
|
|
int (*setup)(void **priv, const char *spec);
|
||
|
|
/* The bus is done with us, so break things down */
|
||
|
|
void (*free)(void *priv);
|
||
|
|
/* The CS has been "activated" -- we won't worry about low/high */
|
||
|
|
void (*cs_activate)(void *priv);
|
||
|
|
/* The CS has been "deactivated" -- we won't worry about low/high */
|
||
|
|
void (*cs_deactivate)(void *priv);
|
||
|
|
/* The client is rx-ing bytes from the bus, so it should tx some */
|
||
|
|
int (*xfer)(void *priv, const u8 *rx, u8 *tx, uint bytes);
|
||
|
|
};
|
||
|
|
|
||
|
|
/*
|
||
|
|
* There are times when the data lines are allowed to tristate. What
|
||
|
|
* is actually sensed on the line depends on the hardware. It could
|
||
|
|
* always be 0xFF/0x00 (if there are pull ups/downs), or things could
|
||
|
|
* float and so we'd get garbage back. This func encapsulates that
|
||
|
|
* scenario so we can worry about the details here.
|
||
|
|
*/
|
||
|
|
static inline void sandbox_spi_tristate(u8 *buf, uint len)
|
||
|
|
{
|
||
|
|
/* XXX: make this into a user config option ? */
|
||
|
|
memset(buf, 0xff, len);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Extract the bus/cs from the spi spec and return the start of the spi
|
||
|
|
* client spec. If the bus/cs are invalid for the current config, then
|
||
|
|
* it returns NULL.
|
||
|
|
*
|
||
|
|
* Example: arg="0:1:foo" will set bus to 0, cs to 1, and return "foo"
|
||
|
|
*/
|
||
|
|
const char *sandbox_spi_parse_spec(const char *arg, unsigned long *bus,
|
||
|
|
unsigned long *cs);
|
||
|
|
|
||
|
|
#endif
|