linux-kernel - Re: [PATCH v3 1/2] dt-bindings: i2c: add binding for i2c-hotplug-gpio

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Message-ID: <ZNvZd2sOK+WMN4XN@shikoro>
Date:   Tue, 15 Aug 2023 22:00:55 +0200
From:   Wolfram Sang <wsa@...nel.org>
To:     Michał Mirosław <mirq-linux@...e.qmqm.pl>
Cc:     Rob Herring <robh@...nel.org>,
        Svyatoslav Ryhel <clamor95@...il.com>,
        Andi Shyti <andi.shyti@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>, linux-i2c@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/2] dt-bindings: i2c: add binding for i2c-hotplug-gpio

> Not a driver but a group of devices (possibly discovered dynamically)
> behind a passive gate (like e.g. PCA9517A with EN tied to a connector pin).
> It's not much different to a I2C gate or mux with a single child bus
> (i2c-mux-gpio that has only a single child).

I agree. To prevent the the bus from spikes when connecting /
disconnecting something like PCA9517A should be in place. And this one
can be considered a 1:1 mux. Just with the exception that Linux cannot
control the gate, but can only react to changes to the enable pin.

Can't we have a driver for the PCA9517 which gets interrupts when the
enable pin changes and then adds / removes the child i2c adapter?

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