[U-Boot] [PATCH V3] mpc5200: reduce delays in i2c

Make the i2c delays smaller. The measured delay is 55us at 100Khz. Set the delay to 15us which should work for 400Khz. 100Khz will loop four times and get a 60us delay. Try four times at a 15us delay and then revert to the previous behavior of 1ms delays. --- cpu/mpc5xxx/i2c.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/cpu/mpc5xxx/i2c.c b/cpu/mpc5xxx/i2c.c index e2506d8..dba9071 100644 --- a/cpu/mpc5xxx/i2c.c +++ b/cpu/mpc5xxx/i2c.c @@ -39,6 +39,7 @@ DECLARE_GLOBAL_DATA_PTR; #endif

#define I2C_TIMEOUT 100 +#define I2C_TIMEOUT_QUICK 4 #define I2C_RETRIES 3

struct mpc5xxx_i2c_tap { @@ -80,7 +81,7 @@ static void mpc_reg_out(volatile u32 *reg, int val, int mask) static int wait_for_bb(void) { struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE; - int timeout = I2C_TIMEOUT; + int timeout = I2C_TIMEOUT + I2C_TIMEOUT_QUICK; int status;

status = mpc_reg_in(&regs->msr); @@ -94,7 +95,7 @@ static int wait_for_bb(void) mpc_reg_out(&regs->mcr, 0, 0); mpc_reg_out(&regs->mcr, I2C_EN, 0); #endif - udelay(1000); + timeout > I2C_TIMEOUT ? udelay(15) : udelay(1000); status = mpc_reg_in(&regs->msr); }

@@ -104,12 +105,12 @@ static int wait_for_bb(void) static int wait_for_pin(int *status) { struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE; - int timeout = I2C_TIMEOUT; + int timeout = I2C_TIMEOUT + I2C_TIMEOUT_QUICK;

*status = mpc_reg_in(&regs->msr);

while (timeout-- && !(*status & I2C_IF)) { - udelay(1000); + timeout > I2C_TIMEOUT ? udelay(15) : udelay(1000); *status = mpc_reg_in(&regs->msr); }