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 --- drivers/i2c/fsl_i2c.c | 24 ++++++++++++++++++++---- 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;