[PATCH 1/2] i2c-core: Add gpio based bus arbitration implementation

Mark Brown broonie at opensource.wolfsonmicro.com
Sat Jan 26 16:00:06 EST 2013


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.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: Digital signature
URL: <http://lists.ozlabs.org/pipermail/devicetree-discuss/attachments/20130126/390a9c21/attachment.sig>


More information about the devicetree-discuss mailing list