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-rw-r--r--drivers/spi/soft_spi.c193
1 files changed, 193 insertions, 0 deletions
diff --git a/drivers/spi/soft_spi.c b/drivers/spi/soft_spi.c
new file mode 100644
index 0000000..25b589a
--- /dev/null
+++ b/drivers/spi/soft_spi.c
@@ -0,0 +1,193 @@
+/*
+ * (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>
+
+#include <malloc.h>
+
+/*-----------------------------------------------------------------------
+ * Definitions
+ */
+
+#ifdef DEBUG_SPI
+#define PRINTD(fmt,args...) printf (fmt ,##args)
+#else
+#define PRINTD(fmt,args...)
+#endif
+
+struct soft_spi_slave {
+ struct spi_slave slave;
+ unsigned int mode;
+};
+
+static inline struct soft_spi_slave *to_soft_spi(struct spi_slave *slave)
+{
+ return container_of(slave, struct soft_spi_slave, slave);
+}
+
+/*=====================================================================*/
+/* Public Functions */
+/*=====================================================================*/
+
+/*-----------------------------------------------------------------------
+ * Initialization
+ */
+void spi_init (void)
+{
+#ifdef SPI_INIT
+ volatile immap_t *immr = (immap_t *)CFG_IMMR;
+
+ SPI_INIT;
+#endif
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+ unsigned int max_hz, unsigned int mode)
+{
+ struct soft_spi_slave *ss;
+
+ if (!spi_cs_is_valid(bus, cs))
+ return NULL;
+
+ ss = malloc(sizeof(struct soft_spi_slave));
+ if (!ss)
+ return NULL;
+
+ ss->slave.bus = bus;
+ ss->slave.cs = cs;
+ ss->mode = mode;
+
+ /* TODO: Use max_hz to limit the SCK rate */
+
+ return &ss->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+ struct soft_spi_slave *ss = to_soft_spi(slave);
+
+ free(ss);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+#ifdef CFG_IMMR
+ volatile immap_t *immr = (immap_t *)CFG_IMMR;
+#endif
+ struct soft_spi_slave *ss = to_soft_spi(slave);
+
+ /*
+ * Make sure the SPI clock is in idle state as defined for
+ * this slave.
+ */
+ if (ss->mode & SPI_CPOL)
+ SPI_SCL(1);
+ else
+ SPI_SCL(0);
+
+ return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+ /* Nothing to do */
+}
+
+/*-----------------------------------------------------------------------
+ * 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).
+ */
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
+ const void *dout, void *din, unsigned long flags)
+{
+#ifdef CFG_IMMR
+ volatile immap_t *immr = (immap_t *)CFG_IMMR;
+#endif
+ struct soft_spi_slave *ss = to_soft_spi(slave);
+ uchar tmpdin = 0;
+ uchar tmpdout = 0;
+ const u8 *txd = dout;
+ u8 *rxd = din;
+ int cpol = ss->mode & SPI_CPOL;
+ int cpha = ss->mode & SPI_CPHA;
+ unsigned int j;
+
+ PRINTD("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
+ slave->bus, slave->cs, *(uint *)txd, *(uint *)rxd, bitlen);
+
+ if (flags & SPI_XFER_BEGIN)
+ spi_cs_activate(slave);
+
+ for(j = 0; j < bitlen; j++) {
+ /*
+ * Check if it is time to work on a new byte.
+ */
+ if((j % 8) == 0) {
+ tmpdout = *txd++;
+ if(j != 0) {
+ *rxd++ = tmpdin;
+ }
+ tmpdin = 0;
+ }
+
+ if (!cpha)
+ SPI_SCL(!cpol);
+ SPI_SDA(tmpdout & 0x80);
+ SPI_DELAY;
+ if (cpha)
+ SPI_SCL(!cpol);
+ else
+ SPI_SCL(cpol);
+ tmpdin <<= 1;
+ tmpdin |= SPI_READ;
+ tmpdout <<= 1;
+ SPI_DELAY;
+ if (cpha)
+ SPI_SCL(cpol);
+ }
+ /*
+ * 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);
+ *rxd++ = tmpdin;
+
+ if (flags & SPI_XFER_END)
+ spi_cs_deactivate(slave);
+
+ return(0);
+}