From: Sakari Ailus <sakari.ailus@linux.intel.com>
To: Krzysztof Kozlowski <krzk@kernel.org>
Cc: devicetree@vger.kernel.org, Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Rob Herring <robh+dt@kernel.org>,
NXP Linux Team <linux-imx@nxp.com>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Fabio Estevam <festevam@gmail.com>,
linux-arm-kernel@lists.infradead.org,
linux-media@vger.kernel.org
Subject: Re: [PATCH v4 1/4] dt-bindings: media: imx258: add bindings for IMX258 sensor
Date: Tue, 29 Sep 2020 14:02:55 +0300 [thread overview]
Message-ID: <20200929110255.GJ26842@paasikivi.fi.intel.com> (raw)
In-Reply-To: <20200929094636.GA11333@kozik-lap>
On Tue, Sep 29, 2020 at 11:46:36AM +0200, Krzysztof Kozlowski wrote:
> On Tue, Sep 29, 2020 at 12:40:46PM +0300, Sakari Ailus wrote:
> > On Tue, Sep 29, 2020 at 11:18:46AM +0200, Krzysztof Kozlowski wrote:
> > > On Tue, 29 Sep 2020 at 11:15, Sakari Ailus <sakari.ailus@linux.intel.com> wrote:
> > > >
> > > > Hi Krzysztof,
> > > >
> > > > On Wed, Sep 23, 2020 at 05:21:26PM +0200, Krzysztof Kozlowski wrote:
> > > > > Add bindings for the IMX258 camera sensor. The bindings, just like the
> > > > > driver, are quite limited, e.g. do not support regulator supplies.
> > > > >
> > > > > Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> > > > >
> > > > > ---
> > > > >
> > > > > Changes since v3:
> > > > > 1. Document also two lane setup.
> > > > >
> > > > > Changes since v2:
> > > > > 1. Remove clock-frequency, add reset GPIOs, add supplies.
> > > >
> > > > Oops. I missed this one.
> > > >
> > > > How does the driver know the appropriate clock frequency for the platform
> > > > if it's not in DT? The sensor supports a range of frequencies, not a single
> > > > frequency.
> > > >
> > > > Could you add clock-frequency back?
> > >
> > > Not really, it was removed on Rob's request. The bindings do not
> > > describe driver's behavior so how the driver gets frequency should not
> > > be part of the bindings. Also it's not a real problem - the driver
> > > just calls clk_get_rate().
> >
> > How is the rate determined? I mean, many ISPs or CSI-2 receivers that
> > provide the clock are also capable of using a variety of frequencies. But
> > only one can be used on the platform in general.
>
> Having "clock-frequency" property in DTS did not solve that. It has no
> effect on actual frequency.
It's up to the driver to do what's needed, yes.
Please see examples in e.g. drivers/media/i2c/ov8856.c and
Documentation/devicetree/bindings/media/i2c/ov8856.yaml .
--
Sakari Ailus
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next prev parent reply other threads:[~2020-09-29 11:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-23 15:21 [PATCH v4 1/4] dt-bindings: media: imx258: add bindings for IMX258 sensor Krzysztof Kozlowski
2020-09-23 15:21 ` [PATCH v4 2/4] media: i2c: imx258: add support for binding via device tree Krzysztof Kozlowski
2020-09-23 15:21 ` [PATCH v4 3/4] media: i2c: imx258: simplify getting state container Krzysztof Kozlowski
2020-09-23 15:21 ` [PATCH v4 4/4] media: i2c: imx258: get clock from device properties and enable it via runtime PM Krzysztof Kozlowski
2020-09-29 9:17 ` Sakari Ailus
2020-09-29 9:24 ` Krzysztof Kozlowski
2020-09-28 18:46 ` [PATCH v4 1/4] dt-bindings: media: imx258: add bindings for IMX258 sensor Rob Herring
2020-09-29 9:15 ` Sakari Ailus
2020-09-29 9:18 ` Krzysztof Kozlowski
2020-09-29 9:40 ` Sakari Ailus
2020-09-29 9:46 ` Krzysztof Kozlowski
2020-09-29 11:02 ` Sakari Ailus [this message]
2020-10-02 12:15 ` Krzysztof Kozlowski
2020-09-29 9:43 ` Sakari Ailus
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