From: Damien Hedde <damien.hedde@greensocs.com>
To: Klaus Jensen <its@irrelevant.dk>, Corey Minyard <minyard@acm.org>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
"Arun Kumar Kashinath Agasar" <arun.kka@samsung.com>,
"Corey Minyard" <cminyard@mvista.com>,
"Andrew Jeffery" <andrew@aj.id.au>,
"Klaus Jensen" <k.jensen@samsung.com>,
qemu-devel@nongnu.org, "Joel Stanley" <joel@jms.id.au>,
qemu-arm@nongnu.org, "Jeremy Kerr" <jk@ozlabs.org>,
"Padmakar Kalghatgi" <p.kalghatgi@samsung.com>,
"Matt Johnston" <matt@codeconstruct.com.au>,
"Cédric Le Goater" <clg@kaod.org>
Subject: Re: [RFC PATCH 0/4] hw/i2c: i2c slave mode support
Date: Fri, 1 Apr 2022 10:58:24 +0200 [thread overview]
Message-ID: <f3c78b1a-bc5c-928c-8986-ad447470b78f@greensocs.com> (raw)
In-Reply-To: <Ykabr0wQe9VLISu2@apples>
On 4/1/22 08:29, Klaus Jensen wrote:
> On Mar 31 15:32, Corey Minyard wrote:
>> On Thu, Mar 31, 2022 at 06:57:33PM +0200, Klaus Jensen wrote:
>>> From: Klaus Jensen <k.jensen@samsung.com>
>>>
>>> Hi all,
>>>
>>> This RFC series adds I2C "slave mode" support for the Aspeed I2C
>>> controller as well as the necessary infrastructure in the i2c core to
>>> support this.
>>
>> I've been wondering when this would happen :). I had put some thought
>> into how this would work, but hadn't come up with anything good.
>>
>> The big disadvantage of this is you are adding an interface that is
>> incompatible with the current masters and slaves. So you are using the
>> same I2C bus, but slaves written this way cannot talk to existing
>> masters, and masters written this way cannot talk to existing slave.
>> You could adapt the masters to be able to work either way, and I suppose
>> some slaves that could do it could have both an async send and a normal
>> send.
>
> Would it make sense to introduce a QOM Interface to differentiate
> between the slave/master types?
>
Probably.
I expect a normal slave-only I2C device will be compatible with any
master (having or having not this feature) in real life ?
It would be great if the compatibility between "a I2C slave requiring
the slave-mode from the bus" and the bus could be checked during the
device plug.
--
Damien
next prev parent reply other threads:[~2022-04-01 9:21 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-31 16:57 [RFC PATCH 0/4] hw/i2c: i2c slave mode support Klaus Jensen
2022-03-31 16:57 ` [RFC PATCH 1/4] hw/i2c: support multiple masters Klaus Jensen
2022-03-31 16:57 ` [RFC PATCH 2/4] hw/i2c: add async send Klaus Jensen
2022-03-31 16:57 ` [RFC PATCH 3/4] hw/i2c: add slave mode for aspeed_i2c Klaus Jensen
2022-03-31 20:44 ` Philippe Mathieu-Daudé
2022-04-01 6:30 ` Klaus Jensen
2022-04-06 6:14 ` Cédric Le Goater
2022-04-06 7:40 ` Klaus Jensen
2022-04-06 8:52 ` Cédric Le Goater
2022-04-06 9:16 ` Klaus Jensen
2022-04-06 9:44 ` Cédric Le Goater
2022-03-31 16:57 ` [RFC PATCH 4/4] hw/misc: add a toy i2c echo device Klaus Jensen
2022-03-31 20:32 ` [RFC PATCH 0/4] hw/i2c: i2c slave mode support Corey Minyard
2022-04-01 6:29 ` Klaus Jensen
2022-04-01 8:58 ` Damien Hedde [this message]
2022-04-01 9:05 ` Klaus Jensen
2022-04-01 13:06 ` Corey Minyard
2022-04-05 20:52 ` Peter Delevoryas
2022-04-06 6:07 ` Klaus Jensen
2022-04-06 17:03 ` Peter Delevoryas
2022-04-06 18:41 ` Klaus Jensen
2022-04-06 22:06 ` Peter Delevoryas
2022-05-06 14:07 ` Jonathan Cameron via
2022-05-06 16:49 ` Cédric Le Goater
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