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From: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
To: Alexander Kochetkov <al.kochet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Stijn Devriendt <highguy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-sh-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Magnus Damm <magnus.damm-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Simon Horman <horms-/R6kz+dDXgpPR4JQBCEnsQ@public.gmane.org>,
	Laurent Pinchart
	<laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>,
	Geert Uytterhoeven
	<geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org>,
	LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Jean Delvare <jdelvare-l3A5Bk7waGM@public.gmane.org>
Subject: Re: [PATCH 2/3] i2c: slave-eeprom: add eeprom simulator driver
Date: Wed, 26 Nov 2014 13:49:01 +0100	[thread overview]
Message-ID: <20141126124901.GB4397@katana> (raw)
In-Reply-To: <2A7C987F-15E0-46FD-A711-E7F5BA9893FC-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

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On Wed, Nov 26, 2014 at 03:25:29PM +0300, Alexander Kochetkov wrote:
> 
> 22 нояб. 2014 г., в 21:12, Wolfram Sang <wsa@the-dreams.de> написал(а):
> 
> > IMO a repeated start is to ensure that two messages arrive at the slave
> > without interruption from another master. I can't think why a slave
> > should know which type of start that was. In fact, if it does that would
> > raise an eyebrow for me. Do you have an example?
> 
> It is used to implement Device ID reading.

Yes and no, I'd say :) Technically, it needs repeated start. But really,
the hardware should handle this (and I know one IP core which has
support for it). One could try to simulate the behaviour in the bus
driver IF a second slave address AND detection of repeated start is
available, but I doubt this combination exists.

Still, all the _slave driver_ needs to handle is an
I2C_SLAVE_EVENT_DEVICE_ID which should return the apropriate value.

That being said, I have never seen querying Device ID in action.

> Not sure, that the feature is really needed for the first release.

I am sure it is not :D

Thanks,

   Wolfram


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WARNING: multiple messages have this Message-ID (diff)
From: Wolfram Sang <wsa@the-dreams.de>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/3] i2c: slave-eeprom: add eeprom simulator driver
Date: Wed, 26 Nov 2014 12:49:01 +0000	[thread overview]
Message-ID: <20141126124901.GB4397@katana> (raw)
In-Reply-To: <2A7C987F-15E0-46FD-A711-E7F5BA9893FC@gmail.com>

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On Wed, Nov 26, 2014 at 03:25:29PM +0300, Alexander Kochetkov wrote:
> 
> 22 нояб. 2014 г., в 21:12, Wolfram Sang <wsa@the-dreams.de> написал(а):
> 
> > IMO a repeated start is to ensure that two messages arrive at the slave
> > without interruption from another master. I can't think why a slave
> > should know which type of start that was. In fact, if it does that would
> > raise an eyebrow for me. Do you have an example?
> 
> It is used to implement Device ID reading.

Yes and no, I'd say :) Technically, it needs repeated start. But really,
the hardware should handle this (and I know one IP core which has
support for it). One could try to simulate the behaviour in the bus
driver IF a second slave address AND detection of repeated start is
available, but I doubt this combination exists.

Still, all the _slave driver_ needs to handle is an
I2C_SLAVE_EVENT_DEVICE_ID which should return the apropriate value.

That being said, I have never seen querying Device ID in action.

> Not sure, that the feature is really needed for the first release.

I am sure it is not :D

Thanks,

   Wolfram


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WARNING: multiple messages have this Message-ID (diff)
From: wsa@the-dreams.de (Wolfram Sang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/3] i2c: slave-eeprom: add eeprom simulator driver
Date: Wed, 26 Nov 2014 13:49:01 +0100	[thread overview]
Message-ID: <20141126124901.GB4397@katana> (raw)
In-Reply-To: <2A7C987F-15E0-46FD-A711-E7F5BA9893FC@gmail.com>

On Wed, Nov 26, 2014 at 03:25:29PM +0300, Alexander Kochetkov wrote:
> 
> 22 ????. 2014 ?., ? 21:12, Wolfram Sang <wsa@the-dreams.de> ???????(?):
> 
> > IMO a repeated start is to ensure that two messages arrive at the slave
> > without interruption from another master. I can't think why a slave
> > should know which type of start that was. In fact, if it does that would
> > raise an eyebrow for me. Do you have an example?
> 
> It is used to implement Device ID reading.

Yes and no, I'd say :) Technically, it needs repeated start. But really,
the hardware should handle this (and I know one IP core which has
support for it). One could try to simulate the behaviour in the bus
driver IF a second slave address AND detection of repeated start is
available, but I doubt this combination exists.

Still, all the _slave driver_ needs to handle is an
I2C_SLAVE_EVENT_DEVICE_ID which should return the apropriate value.

That being said, I have never seen querying Device ID in action.

> Not sure, that the feature is really needed for the first release.

I am sure it is not :D

Thanks,

   Wolfram

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WARNING: multiple messages have this Message-ID (diff)
From: Wolfram Sang <wsa@the-dreams.de>
To: Alexander Kochetkov <al.kochet@gmail.com>
Cc: Stijn Devriendt <highguy@gmail.com>,
	linux-i2c@vger.kernel.org, linux-sh@vger.kernel.org,
	Magnus Damm <magnus.damm@gmail.com>,
	Simon Horman <horms@verge.net.au>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	Jean Delvare <jdelvare@suse.de>
Subject: Re: [PATCH 2/3] i2c: slave-eeprom: add eeprom simulator driver
Date: Wed, 26 Nov 2014 13:49:01 +0100	[thread overview]
Message-ID: <20141126124901.GB4397@katana> (raw)
In-Reply-To: <2A7C987F-15E0-46FD-A711-E7F5BA9893FC@gmail.com>

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On Wed, Nov 26, 2014 at 03:25:29PM +0300, Alexander Kochetkov wrote:
> 
> 22 нояб. 2014 г., в 21:12, Wolfram Sang <wsa@the-dreams.de> написал(а):
> 
> > IMO a repeated start is to ensure that two messages arrive at the slave
> > without interruption from another master. I can't think why a slave
> > should know which type of start that was. In fact, if it does that would
> > raise an eyebrow for me. Do you have an example?
> 
> It is used to implement Device ID reading.

Yes and no, I'd say :) Technically, it needs repeated start. But really,
the hardware should handle this (and I know one IP core which has
support for it). One could try to simulate the behaviour in the bus
driver IF a second slave address AND detection of repeated start is
available, but I doubt this combination exists.

Still, all the _slave driver_ needs to handle is an
I2C_SLAVE_EVENT_DEVICE_ID which should return the apropriate value.

That being said, I have never seen querying Device ID in action.

> Not sure, that the feature is really needed for the first release.

I am sure it is not :D

Thanks,

   Wolfram


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  parent reply	other threads:[~2014-11-26 12:49 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-18 16:04 [PATCH 0/3] i2c: slave support framework for Linux devices Wolfram Sang
2014-11-18 16:04 ` Wolfram Sang
2014-11-18 16:04 ` Wolfram Sang
2014-11-18 16:04 ` Wolfram Sang
     [not found] ` <1416326695-13083-1-git-send-email-wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
2014-11-18 16:04   ` [PATCH 1/3] i2c: core changes for slave support Wolfram Sang
2014-11-18 16:04     ` Wolfram Sang
2014-11-18 16:04     ` Wolfram Sang
2014-11-18 16:04     ` Wolfram Sang
2014-11-18 16:04   ` [PATCH 3/3] i2c: rcar: add " Wolfram Sang
2014-11-18 16:04     ` Wolfram Sang
2014-11-18 16:04     ` Wolfram Sang
2014-11-18 16:04     ` Wolfram Sang
2014-11-18 16:04 ` [PATCH 2/3] i2c: slave-eeprom: add eeprom simulator driver Wolfram Sang
2014-11-18 16:04   ` Wolfram Sang
2014-11-18 16:04   ` Wolfram Sang
2014-11-20 22:39   ` Stijn Devriendt
2014-11-20 22:39     ` Stijn Devriendt
2014-11-20 22:39     ` Stijn Devriendt
2014-11-22 18:12     ` Wolfram Sang
2014-11-22 18:12       ` Wolfram Sang
2014-11-22 18:12       ` Wolfram Sang
2014-11-25 22:07       ` Stijn Devriendt
2014-11-25 22:07         ` Stijn Devriendt
2014-11-25 22:07         ` Stijn Devriendt
2014-11-25 22:07         ` Stijn Devriendt
2014-11-26 12:22         ` Wolfram Sang
2014-11-26 12:22           ` Wolfram Sang
2014-11-26 12:22           ` Wolfram Sang
2014-11-26 12:25       ` Alexander Kochetkov
2014-11-26 12:25         ` Alexander Kochetkov
2014-11-26 12:25         ` Alexander Kochetkov
     [not found]         ` <2A7C987F-15E0-46FD-A711-E7F5BA9893FC-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-11-26 12:49           ` Wolfram Sang [this message]
2014-11-26 12:49             ` Wolfram Sang
2014-11-26 12:49             ` Wolfram Sang
2014-11-26 12:49             ` Wolfram Sang
2014-11-21  7:19   ` Uwe Kleine-König
2014-11-21  7:19     ` Uwe Kleine-König
2014-11-21  7:19     ` Uwe Kleine-König
     [not found]     ` <20141121071941.GK27002-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2014-11-21 14:16       ` Uwe Kleine-König
2014-11-21 14:16         ` Uwe Kleine-König
2014-11-21 14:16         ` Uwe Kleine-König
2014-11-21 14:16         ` Uwe Kleine-König
2014-11-22 18:14         ` Wolfram Sang
2014-11-22 18:14           ` Wolfram Sang
2014-11-22 18:14           ` Wolfram Sang
2014-11-23 18:52           ` Uwe Kleine-König
2014-11-23 18:52             ` Uwe Kleine-König
2014-11-23 18:52             ` Uwe Kleine-König
2014-11-23 18:52             ` Uwe Kleine-König
2014-11-22 18:26       ` Wolfram Sang
2014-11-22 18:26         ` Wolfram Sang
2014-11-22 18:26         ` Wolfram Sang
2014-11-22 18:26         ` Wolfram Sang
2014-11-23 20:20         ` Uwe Kleine-König
2014-11-23 20:20           ` Uwe Kleine-König
2014-11-23 20:20           ` Uwe Kleine-König
2014-11-23 20:20           ` Uwe Kleine-König
     [not found]           ` <20141123202008.GE4431-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2014-11-24 20:40             ` Wolfram Sang
2014-11-24 20:40               ` Wolfram Sang
2014-11-24 20:40               ` Wolfram Sang
2014-11-24 20:40               ` Wolfram Sang
2014-12-11 21:26 ` [PATCH 0/3] i2c: slave support framework for Linux devices Wolfram Sang
2014-12-11 21:26   ` Wolfram Sang
2014-12-11 21:26   ` Wolfram Sang
2014-12-11 21:26   ` Wolfram Sang

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