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Date:   Mon, 24 Apr 2023 14:01:13 +0300
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Subject: Re: [PATCH v11 1/7] i2c: add I2C Address Translator (ATR) support
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From:   Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
To:     Wolfram Sang <wsa@kernel.org>, linux-media@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-i2c@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Luca Ceresoli <luca.ceresoli@bootlin.com>,
        Andy Shevchenko <andriy.shevchenko@intel.com>,
        Matti Vaittinen <Matti.Vaittinen@fi.rohmeurope.com>,
        Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Peter Rosin <peda@axentia.se>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Michael Tretter <m.tretter@pengutronix.de>,
        Hans Verkuil <hverkuil@xs4all.nl>,
        Mike Pagano <mpagano@gentoo.org>,
        =?UTF-8?Q?Krzysztof_Ha=c5=82asa?= <khalasa@piap.pl>,
        Marek Vasut <marex@denx.de>,
        Satish Nagireddy <satish.nagireddy@getcruise.com>,
        Luca Ceresoli <luca@lucaceresoli.net>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>
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On 24/04/2023 13:51, Tomi Valkeinen wrote:
> On 24/04/2023 13:31, Wolfram Sang wrote:
>> On Fri, Apr 21, 2023 at 01:18:27PM +0300, Tomi Valkeinen wrote:
>>> From: Luca Ceresoli <luca@lucaceresoli.net>
>>>
>>> An ATR is a device that looks similar to an i2c-mux: it has an I2C
>>> slave "upstream" port and N master "downstream" ports, and forwards
>>> transactions from upstream to the appropriate downstream port. But it
>>> is different in that the forwarded transaction has a different slave
>>> address. The address used on the upstream bus is called the "alias"
>>> and is (potentially) different from the physical slave address of the
>>> downstream chip.
>>>
>>> Add a helper file (just like i2c-mux.c for a mux or switch) to allow
>>> implementing ATR features in a device driver. The helper takes care or
>>> adapter creation/destruction and translates addresses at each 
>>> transaction.
>>>
>>> Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
>>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>>> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>>
>> This looks good to me. Dunno if the DT folks want the binding as a
>> seperate patch, but this is good to go as far as I am concerned.
> 
> Ah, right. I'll resend with the DT bindings separate.

Also, looks like I forgot to remove the namespaces for export symbols.

  Tomi