From: "Krzysztof Hałasa" <khalasa@piap.pl>
To: Jacopo Mondi <jacopo@jmondi.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
devicetree@vger.kernel.org, linux-media@vger.kernel.org,
linux-kernel@vger.kernel.org,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Sakari Ailus <sakari.ailus@iki.fi>, Joe Perches <joe@perches.com>
Subject: Re: [PATCH v7 2/2] Driver for ON Semi AR0521 camera sensor
Date: Tue, 01 Mar 2022 13:19:20 +0100 [thread overview]
Message-ID: <m3czj57tmf.fsf@t19.piap.pl> (raw)
In-Reply-To: <20220301090132.g5xsodoeotcm6h2q@uno.localdomain> (Jacopo Mondi's message of "Tue, 1 Mar 2022 10:01:32 +0100")
Jacopo Mondi <jacopo@jmondi.org> writes:
>> They can. It appears, though, that clusters aren't about controls which
>> can't change independently. Both of the two are written to the hardware
>> at the same time, which appears to be a valid reason to combine them
>> into a cluster.
>
> Is there a reason to write them to hw at the same time ? :)
Sure, they are written in a single merged burst on I2C.
> As it doesn't seem to me you access registers during probe (to
> identify the sensor in example) there's no need to power up the device
> during probe, but should be enough to let runtime_pm do so when
> requested.
Yes, in fact I never try to read anything from the sensor :-)
Unfortunately I'm not sure how to initialize the (possibly nonexistent)
PM without powering it up, cleanly, in all kernel configs. I mean, I can
check if PM failed and power it up "by hand", but it's a bit messy.
Suggestions are welcome, though.
--
Krzysztof "Chris" Hałasa
Sieć Badawcza Łukasiewicz
Przemysłowy Instytut Automatyki i Pomiarów PIAP
Al. Jerozolimskie 202, 02-486 Warszawa
prev parent reply other threads:[~2022-03-01 12:19 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-03 13:29 [PATCH v7 0/2] On Semi AR0521 sensor driver Krzysztof Hałasa
2022-01-03 13:32 ` [PATCH v7 1/2] dt-binding: media: document ON Semi AR0521 sensor bindings Krzysztof Hałasa
2022-01-03 13:36 ` [PATCH v7 2/2] Driver for ON Semi AR0521 camera sensor Krzysztof Hałasa
2022-01-09 15:34 ` Jacopo Mondi
2022-01-09 19:01 ` Joe Perches
2022-02-25 12:15 ` Krzysztof Hałasa
2022-02-25 13:18 ` Sakari Ailus
2022-02-28 7:48 ` Krzysztof Hałasa
2022-03-01 9:01 ` Jacopo Mondi
2022-03-01 12:19 ` Krzysztof Hałasa [this message]
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