[people/ms/u-boot.git] / common / soft_spi.c

/*
 * (C) Copyright 2002
 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
 *
 * Influenced by code from:
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * 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
 */

#include <common.h>
#include <spi.h>

#if defined(CONFIG_SOFT_SPI)

/*-----------------------------------------------------------------------
 * Definitions
 */

#ifdef DEBUG_SPI
#define PRINTD(fmt,args...)	printf (fmt ,##args)
#else
#define PRINTD(fmt,args...)
#endif


/*=====================================================================*/
/*                         Public Functions                            */
/*=====================================================================*/

/*-----------------------------------------------------------------------
 * Initialization
 */
void spi_init (void)
{
#ifdef	SPI_INIT
	volatile immap_t *immr = (immap_t *)CFG_IMMR;

	SPI_INIT;
#endif
}


/*-----------------------------------------------------------------------
 * 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).
 *
 * If the chipsel() function is not NULL, it is called with a parameter
 * of '1' (chip select active) at the start of the transfer and again with
 * a parameter of '0' at the end of the transfer.
 *
 * If the chipsel() function _is_ NULL, it the responsibility of the
 * caller to make the appropriate chip select active before calling
 * spi_xfer() and making it inactive after spi_xfer() returns.
 */
int  spi_xfer(spi_chipsel_type chipsel, int bitlen, uchar *dout, uchar *din)
{
	volatile immap_t *immr = (immap_t *)CFG_IMMR;
	uchar tmpdin  = 0;
	uchar tmpdout = 0;
	int   j;

	PRINTD("spi_xfer: chipsel %08X dout %08X din %08X bitlen %d\n",
		(int)chipsel, *(uint *)dout, *(uint *)din, bitlen);

	if(chipsel != NULL) {
		(*chipsel)(1);	/* select the target chip */
	}

	for(j = 0; j < bitlen; j++) {
		/*
		 * Check if it is time to work on a new byte.
		 */
		if((j % 8) == 0) {
			tmpdout = *dout++;
			if(j != 0) {
				*din++ = tmpdin;
			}
			tmpdin  = 0;
		}
		SPI_SCL(0);
		SPI_SDA(tmpdout & 0x80);
		SPI_DELAY;
		SPI_SCL(1);
		SPI_DELAY;
		tmpdin  <<= 1;
		tmpdin   |= SPI_READ;
		tmpdout <<= 1;
	}
	/*
	 * If the number of bits isn't a multiple of 8, shift the last
	 * bits over to left-justify them.  Then store the last byte
	 * read in.
	 */
	if((bitlen % 8) != 0)
		tmpdin <<= 8 - (bitlen % 8);
	*din++ = tmpdin;

	SPI_SCL(0);		/* SPI wants the clock left low for idle */

	if(chipsel != NULL) {
		(*chipsel)(0);	/* deselect the target chip */

	}

	return(0);
}

#endif	/* CONFIG_SOFT_SPI */
Commit	Line	Data
e3093091 WD	1	/*
	2	* (C) Copyright 2002
	3	* Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
	4	*
	5	* Influenced by code from:
	6	* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
	7	*
	8	* See file CREDITS for list of people who contributed to this
	9	* project.
	10	*
	11	* This program is free software; you can redistribute it and/or
	12	* modify it under the terms of the GNU General Public License as
	13	* published by the Free Software Foundation; either version 2 of
	14	* the License, or (at your option) any later version.
	15	*
	16	* This program is distributed in the hope that it will be useful,
	17	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	* GNU General Public License for more details.
	20	*
	21	* You should have received a copy of the GNU General Public License
	22	* along with this program; if not, write to the Free Software
	23	* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
	24	* MA 02111-1307 USA
	25	*/
	26
	27	#include <common.h>
	28	#include <spi.h>
	29
	30	#if defined(CONFIG_SOFT_SPI)
	31
e3093091 WD	32	/*-----------------------------------------------------------------------
	33	* Definitions
	34	*/
	35
	36	#ifdef DEBUG_SPI
	37	#define PRINTD(fmt,args...) printf (fmt ,##args)
	38	#else
	39	#define PRINTD(fmt,args...)
	40	#endif
	41
	42
e3093091 WD	43	/=====================================================================/
	44	/* Public Functions */
	45	/=====================================================================/
	46
	47	/*-----------------------------------------------------------------------
	48	* Initialization
	49	*/
	50	void spi_init (void)
	51	{
	52	#ifdef SPI_INIT
	53	volatile immap_t immr = (immap_t )CFG_IMMR;
	54
	55	SPI_INIT;
	56	#endif
	57	}
	58
	59
	60	/*-----------------------------------------------------------------------
	61	* SPI transfer
	62	*
	63	* This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
	64	* "bitlen" bits in the SPI MISO port. That's just the way SPI works.
	65	*
	66	* The source of the outgoing bits is the "dout" parameter and the
	67	* destination of the input bits is the "din" parameter. Note that "dout"
	68	* and "din" can point to the same memory location, in which case the
	69	* input data overwrites the output data (since both are buffered by
	70	* temporary variables, this is OK).
	71	*
	72	* If the chipsel() function is not NULL, it is called with a parameter
	73	* of '1' (chip select active) at the start of the transfer and again with
	74	* a parameter of '0' at the end of the transfer.
	75	*
	76	* If the chipsel() function _is_ NULL, it the responsibility of the
	77	* caller to make the appropriate chip select active before calling
	78	* spi_xfer() and making it inactive after spi_xfer() returns.
	79	*/
	80	int spi_xfer(spi_chipsel_type chipsel, int bitlen, uchar dout, uchar din)
	81	{
	82	volatile immap_t immr = (immap_t )CFG_IMMR;
	83	uchar tmpdin = 0;
	84	uchar tmpdout = 0;
	85	int j;
	86
	87	PRINTD("spi_xfer: chipsel %08X dout %08X din %08X bitlen %d\n",
	88	(int)chipsel, (uint )dout, (uint )din, bitlen);
	89
	90	if(chipsel != NULL) {
	91	(chipsel)(1); / select the target chip */
	92	}
	93
	94	for(j = 0; j < bitlen; j++) {
	95	/*
	96	* Check if it is time to work on a new byte.
	97	*/
	98	if((j % 8) == 0) {
	99	tmpdout = *dout++;
	100	if(j != 0) {
	101	*din++ = tmpdin;
	102	}
	103	tmpdin = 0;
	104	}
	105	SPI_SCL(0);
	106	SPI_SDA(tmpdout & 0x80);
107	SPI_DELAY;
108	SPI_SCL(1);
109	SPI_DELAY;
110	tmpdin <<= 1;
111	tmpdin \|= SPI_READ;
112	tmpdout <<= 1;
113	}
114	/*
115	* If the number of bits isn't a multiple of 8, shift the last
116	* bits over to left-justify them. Then store the last byte
117	* read in.
118	*/
119	if((bitlen % 8) != 0)
120	tmpdin <<= 8 - (bitlen % 8);
121	*din++ = tmpdin;
122
123	SPI_SCL(0); /* SPI wants the clock left low for idle */
124
125	if(chipsel != NULL) {
126	(chipsel)(0); / deselect the target chip */
127
128	}
129
130	return(0);
131	}
132
133	#endif /* CONFIG_SOFT_SPI */