[U-Boot] [MPC8379E-rdb] Question about master bus busy after enabling I2C.

Heiko Schocher hs at denx.de
Mon Sep 5 08:29:58 CEST 2011


Hello shawn,

shawn Bai wrote:
> Hi, here is a question about I2C initialization.
>  
> I2C driver of our own references i2c driver implemented in fsl_i2c.c
>  
> The init flow is almost the same.
>  
> After writing enable-bit MEN into i2c control register to enable I2C controler, 
>  
> sometimes, Bit 2 in i2c status, MBB bit, will be set, indicating i2c master bus busy.
>  
> And this will cause wait4bus return with failing.
>  
> Is there anyone around who used to face this question?
>  
> Or is there any suggestion or advice anyway?

Try a look in u-boot/doc/I2C_Edge_Conditions. Maybe your I2C bus
is left in a blocked state, so try to deblock it. As for an example
look in

board/keymile/common/common.c

There is a deblock sequence also for MPC83xx, maybe this helps you.

bye,
Heiko
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