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authorTimur Tabi <timur@freescale.com>2009-09-04 16:28:35 -0500
committerHeiko Schocher <hs@denx.de>2009-09-06 11:26:05 +0200
commit92477a631bbda2dc0dd2194e03f9bd3ddb8b9c21 (patch)
tree4c561c855f31f38c44f2e06175b931b12247bc9e /drivers
parent5da71efa18e8b4eac9afd8bfa13e3c7e7ddde1d0 (diff)
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fsl_i2c: increase I2C timeout values and make them configurable
The value of I2C_TIMEOUT in fsl_i2c.c has several problems. First, it is defined as CONFIG_HZ/4, but it is used as a count of microseconds, so it makes no sense to derive it from a clock rate. Second, the current value (250) is too low for some boards, so it needs to be increased. Third, the timeout necessary for multiple-master arbitration is larger than the timeout for basic read/write operations, so we shouldn't have a single constant for both timeouts. Finally, it would be nice if we could override these values on a per-board basis. Signed-off-by: Timur Tabi <timur@freescale.com> Acked-by: Wolfgang Denk <wd@denx.de> Tested-by: Peter Tyser <ptyser@xes-inc.com> Acked-by: Peter Tyser <ptyser@xes-inc.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/i2c/fsl_i2c.c24
1 files changed, 20 insertions, 4 deletions
diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c
index ce0f301..47bbf79 100644
--- a/drivers/i2c/fsl_i2c.c
+++ b/drivers/i2c/fsl_i2c.c
@@ -1,5 +1,5 @@
/*
- * Copyright 2006 Freescale Semiconductor, Inc.
+ * Copyright 2006,2009 Freescale Semiconductor, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
@@ -26,7 +26,21 @@
#include <asm/io.h>
#include <asm/fsl_i2c.h> /* HW definitions */
-#define I2C_TIMEOUT (CONFIG_SYS_HZ / 4)
+/* The maximum number of microseconds we will wait until another master has
+ * released the bus. If not defined in the board header file, then use a
+ * generic value.
+ */
+#ifndef CONFIG_I2C_MBB_TIMEOUT
+#define CONFIG_I2C_MBB_TIMEOUT 100000
+#endif
+
+/* The maximum number of microseconds we will wait for a read or write
+ * operation to complete. If not defined in the board header file, then use a
+ * generic value.
+ */
+#ifndef CONFIG_I2C_TIMEOUT
+#define CONFIG_I2C_TIMEOUT 10000
+#endif
#define I2C_READ_BIT 1
#define I2C_WRITE_BIT 0
@@ -213,9 +227,10 @@ static __inline__ int
i2c_wait4bus(void)
{
unsigned long long timeval = get_ticks();
+ const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
while (readb(&i2c_dev[i2c_bus_num]->sr) & I2C_SR_MBB) {
- if ((get_ticks() - timeval) > usec2ticks(I2C_TIMEOUT))
+ if ((get_ticks() - timeval) > timeout)
return -1;
}
@@ -227,6 +242,7 @@ i2c_wait(int write)
{
u32 csr;
unsigned long long timeval = get_ticks();
+ const unsigned long long timeout = usec2ticks(CONFIG_I2C_TIMEOUT);
do {
csr = readb(&i2c_dev[i2c_bus_num]->sr);
@@ -251,7 +267,7 @@ i2c_wait(int write)
}
return 0;
- } while ((get_ticks() - timeval) < usec2ticks(I2C_TIMEOUT));
+ } while ((get_ticks() - timeval) < timeout);
debug("i2c_wait: timed out\n");
return -1;