From: Wolfram Sang <wsa@kernel.org>
To: Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: kernel@axis.com, linux-i2c@vger.kernel.org,
devicetree@vger.kernel.org, krzk+dt@kernel.org,
robh+dt@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] dt-bindings: i2c: add property to avoid device detection
Date: Sat, 14 May 2022 16:26:16 +0200 [thread overview]
Message-ID: <Yn+8CJ3j2SY2+Mq+@shikoro> (raw)
In-Reply-To: <20220412085046.1110127-2-vincent.whitchurch@axis.com>
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On Tue, Apr 12, 2022 at 10:50:45AM +0200, Vincent Whitchurch wrote:
> When drivers with ->detect callbacks are loaded, the I2C core does a
> bunch of transactions to try to probe for these devices, regardless of
> whether they are specified in the devicetree or not. (This only happens
> on I2C controllers whose drivers enable the I2C_CLASS* flags, but this
> is the case for generic drivers like i2c-gpio.)
>
> These kinds of transactions are unnecessary on systems where the
> devicetree specifies all the devices on the I2C bus, so add a property
> to indicate that the devicetree description of the hardware is complete
> and thus allow this discovery to be disabled.
Hmm, I don't think the name is fitting. "no-detect" is the desired
behaviour but a proper description is more like "bus-complete" or
something?
That aside, I am not sure we should handle this at DT level. Maybe we
should better change the GPIO driver to not populate a class if we have
a firmware node?
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next prev parent reply other threads:[~2022-05-14 14:26 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-12 8:50 [PATCH v2 0/2] i2c: Allow disabling auto detection via devicetree Vincent Whitchurch
2022-04-12 8:50 ` [PATCH v2 1/2] dt-bindings: i2c: add property to avoid device detection Vincent Whitchurch
2022-04-12 8:52 ` Krzysztof Kozlowski
2022-04-12 21:22 ` Rob Herring
2022-04-14 8:55 ` Vincent Whitchurch
2022-04-14 19:40 ` Rob Herring
2022-05-14 14:26 ` Wolfram Sang [this message]
2022-05-16 6:43 ` Vincent Whitchurch
2022-05-16 7:12 ` Wolfram Sang
2022-05-16 7:57 ` Peter Rosin
2022-05-16 8:07 ` Peter Rosin
2022-05-18 16:09 ` Luca Ceresoli
2022-04-12 8:50 ` [PATCH v2 2/2] i2c: core: support no-detect property Vincent Whitchurch
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