[U-Boot] [PATCH 1/2] Add driver for the ST M95xxx SPI EEPROM

[Albin Tonnerre]

This chip is used in a number of boards manufactured by Calao-Systems
which should be supported soon. This driver provides the necessary
spi_read and spi_write functions necessary to communicate with the chip.

Signed-off-by: Albin Tonnerre <albin.tonnerre at free-electrons.com>
---
 drivers/spi/Makefile        |    1 +
 drivers/spi/eeprom_m95xxx.c |  115 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 116 insertions(+), 0 deletions(-)
 create mode 100644 drivers/spi/eeprom_m95xxx.c

diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index a9f67a0..35c9e02 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -33,6 +33,7 @@ COBJS-$(CONFIG_MPC52XX_SPI) += mpc52xx_spi.o
 COBJS-$(CONFIG_MPC8XXX_SPI) += mpc8xxx_spi.o
 COBJS-$(CONFIG_MXC_SPI) += mxc_spi.o
 COBJS-$(CONFIG_SOFT_SPI) += soft_spi.o
+COBJS-$(CONFIG_M95XXX_SPI) += eeprom_m95xxx.o
 
 COBJS	:= $(COBJS-y)
 SRCS	:= $(COBJS:.o=.c)
diff --git a/drivers/spi/eeprom_m95xxx.c b/drivers/spi/eeprom_m95xxx.c
new file mode 100644
index 0000000..9298c9f
--- /dev/null
+++ b/drivers/spi/eeprom_m95xxx.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2009
+ * Albin Tonnerre, Free Electrons <albin.tonnerre at free-electrons.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
+ */
+
+#include <common.h>
+#include <spi.h>
+
+#define SPI_EEPROM_WREN		0x06
+#define SPI_EEPROM_RDSR		0x05
+#define SPI_EEPROM_READ		0x03
+#define SPI_EEPROM_WRITE	0x02
+
+#ifndef CONFIG_DEFAULT_SPI_BUS
+#define CONFIG_DEFAULT_SPI_BUS 0
+#endif
+
+#ifndef CONFIG_DEFAULT_SPI_MODE
+#define CONFIG_DEFAULT_SPI_MODE SPI_MODE_0
+#endif
+
+ssize_t spi_read (uchar *addr, int alen, uchar *buffer, int len)
+{
+	struct spi_slave *slave;
+	u8 cmd = SPI_EEPROM_READ;
+
+	slave = spi_setup_slave(CONFIG_DEFAULT_SPI_BUS, 1, 1000000,
+			CONFIG_DEFAULT_SPI_MODE);
+	spi_claim_bus(slave);
+
+	/* command */
+	if(spi_xfer(slave, 8, &cmd, NULL, SPI_XFER_BEGIN))
+		return -1;
+
+	/* if alen == 3, addr[0] is the block number, we never use it here. All we
+	 * need are the lower 16 bits*/
+	if (alen == 3)
+		addr++;
+
+	/* address, and data */
+	if(spi_xfer(slave, 16, addr, NULL, 0))
+		return -1;
+	if(spi_xfer(slave, 8*len, NULL, buffer, SPI_XFER_END))
+		return -1;
+
+	spi_release_bus(slave);
+	spi_free_slave(slave);
+	return len;
+}
+
+ssize_t spi_write (uchar *addr, int alen, uchar *buffer, int len)
+{
+	struct spi_slave *slave;
+	int i;
+	char buf[3];
+
+	slave = spi_setup_slave(CONFIG_DEFAULT_SPI_BUS, 1, 1000000,
+			CONFIG_DEFAULT_SPI_MODE);
+	spi_claim_bus(slave);
+
+	buf[0] = SPI_EEPROM_WREN;
+	if(spi_xfer(slave, 8, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END))
+		return -1;
+
+	buf[0] = SPI_EEPROM_WRITE;
+
+	/* As for reading, drop addr[0] if alen is 3 */
+	if (alen == 3) {
+		alen--;
+		addr++;
+	}
+
+	memcpy(buf+1, addr, alen);
+	/* command + addr, then data */
+	if(spi_xfer(slave, 24, buf, NULL, SPI_XFER_BEGIN))
+		return -1;
+	if(spi_xfer(slave, len*8, buffer, NULL, SPI_XFER_END))
+		return -1;
+
+	for (i = 0; i < 1000; i++) {
+		buf[0] = SPI_EEPROM_RDSR;
+		buf[1] = 0;
+		spi_xfer(slave, 16, buf, buf, SPI_XFER_BEGIN | SPI_XFER_END);
+
+		if (!(buf[1] & 1)) {
+			break;
+		}
+		udelay(1000);
+	}
+	if (i >= 1000) {
+		printf ("*** spi_write: Time out while writing!\n");
+	}
+
+	spi_release_bus(slave);
+	spi_free_slave(slave);
+	return len;
+}
-- 
1.6.3.3