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Date:   Mon, 24 Apr 2023 12:31:26 +0200
From:   Wolfram Sang <wsa@kernel.org>
To:     Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Cc:     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>,
        Krzysztof =?utf-8?Q?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>
Subject: Re: [PATCH v11 1/7] i2c: add I2C Address Translator (ATR) support
Message-ID: <ZEZafj6j+EurGWJ7@sai>
Mail-Followup-To: Wolfram Sang <wsa@kernel.org>,
        Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>,
        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>,
        Krzysztof =?utf-8?Q?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>
References: <20230421101833.345984-1-tomi.valkeinen@ideasonboard.com>
 <20230421101833.345984-2-tomi.valkeinen@ideasonboard.com>
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On Fri, Apr 21, 2023 at 01:18:27PM +0300, Tomi Valkeinen wrote:
> From: Luca Ceresoli <luca@lucaceresoli.net>
>=20
> 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.
>=20
> 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.
>=20
> 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.
Everything else can be fixed incrementally, I think. Also, this can go
in via the media-tree, there shouldn't be any conflicts.

Acked-by: Wolfram Sang <wsa@kernel.org>

Thanks for keeping at it!


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