[U-Boot] [PATCH v2 12/16] [PATCH] mgcoge, mgsuvd: add boardspecific I2C deblocking mechanism.

Heiko Schocher
2008-10-15T07:39:08Z

As Documented in doc/I2C_Edge_Conditions, adding a
boardspecific deblocking mechansim via CFG_I2C_INIT_BOARD
for the mgcoge and mgsuvd board.

This code was originally written by keymile in association
with Anatech and Atmel in 1998. The Code toggels the SCL
until the SCA line goes to High (max. 16 times).
And after this, a start Condition is send.

This is another approach to deblock the I2C Bus. The
soft I2C driver actually sends 9 clocks with SDA High,
and then a stop at the end, to deblock the I2C Bus.

Maybe we should use the approach from keymile as
the new standard?

Signed-off-by: Heiko Schocher <hs@denx.de>
---
board/keymile/common/common.c | 209 +++++++++++++++++++++++++++++++++++++++++
board/keymile/mgcoge/Makefile | 2 +-
board/keymile/mgsuvd/Makefile | 2 +-
include/configs/mgcoge.h | 1 +
include/configs/mgsuvd.h | 1 +
5 files changed, 213 insertions(+), 2 deletions(-)
create mode 100644 board/keymile/common/common.c

diff --git a/board/keymile/common/common.c b/board/keymile/common/common.c
new file mode 100644
index 0000000..13b80fe
--- /dev/null
+++ b/board/keymile/common/common.c
@@ -0,0 +1,209 @@
+/*
+ * (C) Copyright 2008
+ * Heiko Schocher, DENX Software Engineering, hs at 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 <mpc8260.h>
+#include <ioports.h>
+#include <malloc.h>
+
+#if defined(CONFIG_OF_BOARD_SETUP) && defined(CONFIG_OF_LIBFDT)
+#include <libfdt.h>
+#endif
+
+#if defined(CONFIG_HARD_I2C) || defined(CONFIG_SOFT_I2C)
+#include <i2c.h>
+#endif
+
+extern int i2c_soft_read_pin (void);
+
+#if defined(CFG_I2C_INIT_BOARD)
+#define DELAY_ABORT_SEQ 62
+#define DELAY_HALF_PERIOD (500 / (CFG_I2C_SPEED / 1000))
+
+#if defined(CONFIG_MGCOGE)
+#define SDA_MASK 0x00010000
+#define SCL_MASK 0x00020000
+static void set_pin (int state, unsigned long mask)
+{
+ volatile ioport_t *iop = ioport_addr ((immap_t *)CFG_IMMR, 3);
+
+ if (state)
+ iop->pdat |= (mask);
+ else
+ iop->pdat &= ~(mask);
+
+ iop->pdir |= (mask);
+}
+
+static int get_pin (unsigned long mask)
+{
+ volatile ioport_t *iop = ioport_addr ((immap_t *)CFG_IMMR, 3);
+
+ iop->pdir &= ~(mask);
+ return (0 != (iop->pdat & (mask)));
+}
+
+static void set_sda (int state)
+{
+ set_pin (state, SDA_MASK);
+}
+
+static void set_scl (int state)
+{
+ set_pin (state, SCL_MASK);
+}
+
+static int get_sda (void)
+{
+ return get_pin (SDA_MASK);
+}
+
+static int get_scl (void)
+{
+ return get_pin (SCL_MASK);
+}
+
+#if defined(CONFIG_HARD_I2C)
+static void setports (int gpio)
+{
+ volatile ioport_t *iop = ioport_addr ((immap_t *)CFG_IMMR, 3);
+
+ if (gpio) {
+ iop->ppar &= ~(SDA_MASK | SCL_MASK);
+ iop->podr &= ~(SDA_MASK | SCL_MASK);
+ } else {
+ iop->ppar |= (SDA_MASK | SCL_MASK);
+ iop->pdir &= ~(SDA_MASK | SCL_MASK);
+ iop->podr |= (SDA_MASK | SCL_MASK);
+ }
+}
+#endif
+#endif
+
+#if defined(CONFIG_MGSUVD)
+static void set_sda (int state)
+{
+ I2C_SDA(state);
+}
+
+static void set_scl (int state)
+{
+ I2C_SCL(state);
+}
+
+static int get_sda (void)
+{
+ return i2c_soft_read_pin ();
+}
+
+static int get_scl (void)
+{
+ int val;
+
+ *(unsigned short *)(I2C_BASE_DIR) &= ~SCL_CONF;
+ udelay (1);
+ val = *(unsigned char *)(I2C_BASE_PORT);
+
+ return ((val & SCL_BIT) == SCL_BIT);
+}
+
+#endif
+
+static void writeStartSeq (void)
+{
+ set_sda (1);
+ udelay (DELAY_HALF_PERIOD);
+ set_scl (1);
+ udelay (DELAY_HALF_PERIOD);
+ set_sda (0);
+ udelay (DELAY_HALF_PERIOD);
+ set_scl (0);
+ udelay (DELAY_HALF_PERIOD);
+}
+
+/* I2C is a synchronous protocol and resets of the processor in the middle
+ of an access can block the I2C Bus until a powerdown of the full unit is
+ done. This function toggles the SCL until the SCL and SCA line are
+ released, but max. 16 times, after this a I2C start-sequence is sent.
+ This I2C Deblocking mechanism was developed by Keymile in association
+ with Anatech and Atmel in 1998.
+ */
+static int i2c_make_abort (void)
+{
+ int scl_state = 0;
+ int sda_state = 0;
+ int i = 0;
+ int ret = 0;
+
+ if (!get_sda ()) {
+ ret = -1;
+ while (i < 16) {
+ i++;
+ set_scl (0);
+ udelay (DELAY_ABORT_SEQ);
+ set_scl (1);
+ udelay (DELAY_ABORT_SEQ);
+ scl_state = get_scl ();
+ sda_state = get_sda ();
+ if (scl_state && sda_state) {
+ ret = 0;
+ break;
+ }
+ }
+ }
+ if (ret == 0) {
+ for (i =0; i < 5; i++) {
+ writeStartSeq ();
+ }
+ }
+ get_sda ();
+ return ret;
+}
+
+/**
+ * i2c_init_board - reset i2c bus. When the board is powercycled during a
+ * bus transfer it might hang; for details see doc/I2C_Edge_Conditions.
+ */
+void i2c_init_board(void)
+{
+#if defined(CONFIG_HARD_I2C)
+ volatile immap_t *immap = (immap_t *)CFG_IMMR ;
+ volatile i2c8260_t *i2c = (i2c8260_t *)&immap->im_i2c;
+
+ /* disable I2C controller first, otherwhise it thinks we want to */
+ /* talk to the slave port... */
+ i2c->i2c_i2mod &= ~0x01;
+
+ /* Set the PortPins to GPIO */
+ setports (1);
+#endif
+
+ /* Now run the AbortSequence() */
+ i2c_make_abort ();
+
+#if defined(CONFIG_HARD_I2C)
+ /* Set the PortPins back to use for I2C */
+ setports (0);
+#endif
+}
+#endif
diff --git a/board/keymile/mgcoge/Makefile b/board/keymile/mgcoge/Makefile
index d4087cc..cbf7129 100644
--- a/board/keymile/mgcoge/Makefile
+++ b/board/keymile/mgcoge/Makefile
@@ -25,7 +25,7 @@ include $(TOPDIR)/config.mk

LIB = $(obj)lib$(BOARD).a

-COBJS := $(BOARD).o
+COBJS := $(BOARD).o ../common/common.o

SRCS := $(SOBJS:.o=.S) $(COBJS:.o=.c)
OBJS := $(addprefix $(obj),$(COBJS))
diff --git a/board/keymile/mgsuvd/Makefile b/board/keymile/mgsuvd/Makefile
index af0d400..0326608 100644
--- a/board/keymile/mgsuvd/Makefile
+++ b/board/keymile/mgsuvd/Makefile
@@ -25,7 +25,7 @@ include $(TOPDIR)/config.mk

LIB = $(obj)lib$(BOARD).a

-COBJS = $(BOARD).o
+COBJS = $(BOARD).o ../common/common.o

SRCS := $(SOBJS:.o=.S) $(COBJS:.o=.c)
OBJS := $(addprefix $(obj),$(COBJS))
diff --git a/include/configs/mgcoge.h b/include/configs/mgcoge.h
index bfbbd45..398e092 100644
--- a/include/configs/mgcoge.h
+++ b/include/configs/mgcoge.h
@@ -202,6 +202,7 @@
#define CONFIG_I2C_MULTI_BUS 1
#define CONFIG_I2C_CMD_TREE 1
#define CFG_MAX_I2C_BUS 2
+#define CFG_I2C_INIT_BOARD 1

/* EEprom support */
#define CFG_I2C_EEPROM_ADDR_LEN 1
diff --git a/include/configs/mgsuvd.h b/include/configs/mgsuvd.h
index c569c81..2048575 100644
--- a/include/configs/mgsuvd.h
+++ b/include/configs/mgsuvd.h
@@ -373,6 +373,7 @@
#define CONFIG_I2C_MULTI_BUS 1
#define CONFIG_I2C_CMD_TREE 1
#define CFG_MAX_I2C_BUS 2
+#define CFG_I2C_INIT_BOARD 1

/* EEprom support */
#define CFG_I2C_EEPROM_ADDR_LEN 1
--
1.5.6.1

--
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