Re: [PATCH 1/2] i2c-core: Add gpio based bus arbitrationimplementation

From: Mark Brown
Date: Sat Jan 26 2013 - 00:00:16 EST


On Thu, Jan 24, 2013 at 12:39:48PM +0100, Wolfram Sang wrote:
> On Thu, Jan 24, 2013 at 07:18:47PM +0800, Mark Brown wrote:

> > A read is typically implemented as a write of the register address
> > followed by a read of the value, usually with the ability to free the
> > bus in between. If two devices attempt to access the register map
> > simultaneously this results in the address going wrong.

> Could happen. But in what situations will one not use repeated start
> here? Especially when designing a multi-master bus?

Well, you're depending on the specific drivers doing things that way and
it's actually quite rare for the controller drivers in Linux to support
I2C_M_NOSTART which discourages this.

Attachment: signature.asc
Description: Digital signature