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

Albin Tonnerre
2009-08-05T17:16:41Z

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@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@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