From e3093091a9d0e7a0709ee79390414b5a5ca69f88 Mon Sep 17 00:00:00 2001
From: wdenk <wdenk>
Date: Tue, 1 Oct 2002 01:07:28 +0000
Subject: Initial revision

---
 common/soft_spi.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 common/soft_spi.c

(limited to 'common/soft_spi.c')

diff --git a/common/soft_spi.c b/common/soft_spi.c
new file mode 100644
index 0000000..a5b62f2
--- /dev/null
+++ b/common/soft_spi.c
@@ -0,0 +1,138 @@
+/*
+ * (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)
+
+#define DEBUG_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 */
+
-- 
cgit v1.1