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fsl_i2c: increase I2C timeout values and make them configurable

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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>
This commit is contained in:
Timur Tabi 2009-09-04 16:28:35 -05:00 committed by Heiko Schocher
parent 5da71efa18
commit 92477a631b
1 changed files with 20 additions and 4 deletions
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24
drivers/i2c/fsl_i2c.c
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@ -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;