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From: Guenter Roeck <guenter.roeck-IzeFyvvaP7pWk0Htik3J/w@public.gmane.org>
To: Michael Lawnick <ml.lawnick-Mmb7MZpHnFY@public.gmane.org>
Cc: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>,
	"linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Rodolfo Giometti
	<giometti-AVVDYK/kqiJWk0Htik3J/w@public.gmane.org>
Subject: Re: Driver for pca9541 bus master selector
Date: Thu, 30 Sep 2010 00:48:47 -0700	[thread overview]
Message-ID: <20100930074847.GA17693@ericsson.com> (raw)
In-Reply-To: <4CA42750.5020500-Mmb7MZpHnFY@public.gmane.org>

On Thu, Sep 30, 2010 at 01:59:44AM -0400, Michael Lawnick wrote:
[ ... ]

> I only took a rough look, but it seemed to me that the pca is part of
> the main device.

Yes

> From abstraction side of view your problem seems a matter of
> synchronization of two independent computer systems. You will need a
> shared resource. The access to it could either be part of driver code or
> by introducing a 'one-channel multiplexer' as you did. But the sync
> needs to be done by your code via a shared data object.
> 
Actually, the pca9541 has a bit in its register set which I can use.
See NTESTON in its control register. That is visible as interrupt status
at the other master. That is all I need, and reduces complexity significantly.

Thanks,
Guenter

  parent reply	other threads:[~2010-09-30  7:48 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-28 14:33 Driver for pca9541 bus master selector Guenter Roeck
     [not found] ` <20100928143302.GA7593-IzeFyvvaP7pWk0Htik3J/w@public.gmane.org>
2010-09-28 15:16   ` Jean Delvare
     [not found]     ` <20100928171607.395f7736-R0o5gVi9kd7kN2dkZ6Wm7A@public.gmane.org>
2010-09-28 16:07       ` Guenter Roeck
     [not found]         ` <20100928160746.GB7976-IzeFyvvaP7pWk0Htik3J/w@public.gmane.org>
2010-09-28 16:42           ` Jean Delvare
     [not found]             ` <20100928184215.00f82717-R0o5gVi9kd7kN2dkZ6Wm7A@public.gmane.org>
2010-09-28 17:16               ` Guenter Roeck
     [not found]                 ` <20100928171627.GA8415-IzeFyvvaP7pWk0Htik3J/w@public.gmane.org>
2010-09-29  7:19                   ` Jean Delvare
     [not found]                     ` <20100929091928.16256bb7-R0o5gVi9kd7kN2dkZ6Wm7A@public.gmane.org>
2010-09-29 13:54                       ` Guenter Roeck
     [not found]                         ` <20100929135401.GA11771-IzeFyvvaP7pWk0Htik3J/w@public.gmane.org>
2010-09-30  5:59                           ` Michael Lawnick
     [not found]                             ` <4CA42750.5020500-Mmb7MZpHnFY@public.gmane.org>
2010-09-30  7:48                               ` Guenter Roeck [this message]
2010-10-13 16:05                           ` Guenter Roeck
2010-10-13 15:45                     ` Guenter Roeck

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