From: Sakari Ailus <sakari.ailus@iki.fi>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>,
robh+dt@kernel.org, devicetree@vger.kernel.org,
slongerbeam@gmail.com, linux-media@vger.kernel.org,
linux-renesas-soc@vger.kernel.org,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@st.com>,
"moderated list:ARM/STM32 ARCHITECTURE"
<linux-stm32@st-md-mailman.stormreply.com>
Subject: Re: [PATCH 08/13] dt-bindings: media: ov5640: Remove data-shift
Date: Sun, 26 Jul 2020 00:18:33 +0300 [thread overview]
Message-ID: <20200725211833.GE829@valkosipuli.retiisi.org.uk> (raw)
In-Reply-To: <20200723231549.GE21353@pendragon.ideasonboard.com>
Hi Laurent,
On Fri, Jul 24, 2020 at 02:15:49AM +0300, Laurent Pinchart wrote:
> Hi Sakari,
>
> On Fri, Jul 24, 2020 at 01:22:59AM +0300, Sakari Ailus wrote:
> > On Fri, Jul 17, 2020 at 11:57:22PM +0300, Laurent Pinchart wrote:
> > > Hi Jacopo,
> > >
> > > (CC'ing Sakari)
> > >
> > > Thank you for the patch.
> > >
> > > On Fri, Jul 17, 2020 at 03:28:54PM +0200, Jacopo Mondi wrote:
> > > > The value of the data-shift property solely depend on the selected
> > > > bus width and it's not freely configurable.
> > > >
> > > > Remove it from the bindings document and update its users accordingly.
> > >
> > > Hmmmm that's an interesting one. Sakari, what do you think ?
> > >
> > > > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > > > ---
> > > > Documentation/devicetree/bindings/media/i2c/ov5640.yaml | 9 ---------
> > > > arch/arm/boot/dts/stm32mp157c-ev1.dts | 1 -
> > > > 2 files changed, 10 deletions(-)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/media/i2c/ov5640.yaml b/Documentation/devicetree/bindings/media/i2c/ov5640.yaml
> > > > index 5e1662e848bd..ab700a1830aa 100644
> > > > --- a/Documentation/devicetree/bindings/media/i2c/ov5640.yaml
> > > > +++ b/Documentation/devicetree/bindings/media/i2c/ov5640.yaml
> > > > @@ -92,12 +92,6 @@ properties:
> > > > parallel bus.
> > > > enum: [8, 10]
> > > >
> > > > - data-shift:
> > > > - description: |
> > > > - Shall be set to <2> for 8 bits parallel bus (lines 9:2 are used) or
> > > > - <0> for 10 bits parallel bus.
> > > > - enum: [0, 2]
> > >
> > > Should you document in the description of bus-width that data-shift is
> > > implied ?
> >
> > The purpose of the datas-shift property is to convey how the parallel bus
> > lines are connected for a given bus width for devices where it is
> > configurable. As this device does not not support that, then indeed this
> > property is not relevant for the device IMO.
>
> Could you elaborate on this ? I believe the case that Jacopo is
> describing connects D[9:2] from the sensor to D[7:0] of the receiver
> (Jacopo, could you confirm ?). Isn't that what data-shift is for ?
Yes, it is. But in this case what data-shift configures is not configurable
as such but defined by another configuration, making the data-shift
property redundant. We generally haven't documented redundant things in DT
bindings --- for instance data-lanes is documented in bindings only if it
is configurable.
That said, it'd be nice to say which pins are used on less than full width
busses.
--
Regards,
Sakari Ailus
next prev parent reply other threads:[~2020-07-25 21:19 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-17 13:28 [PATCH 00/13] dt-bindings: media: ov5640: Convert to json-schema Jacopo Mondi
2020-07-17 13:28 ` [PATCH 01/13] " Jacopo Mondi
2020-07-17 19:28 ` Laurent Pinchart
2020-07-20 16:32 ` Rob Herring
2020-07-17 13:28 ` [PATCH 02/13] arm64: dts: qcom: apq8016-sbc: Fix CSI-2 lanes routing Jacopo Mondi
2020-07-17 19:35 ` Laurent Pinchart
2020-07-22 8:14 ` Loic Poulain
2020-07-22 8:34 ` Jacopo Mondi
2020-07-17 13:28 ` [PATCH 03/13] dt-bindings: media: ov5640: Do not limit rotation Jacopo Mondi
2020-07-17 19:38 ` Laurent Pinchart
2020-07-20 19:36 ` Rob Herring
2020-07-17 13:28 ` [PATCH 04/13] dt-bindings: media: ti,cal: Remove sensor from example Jacopo Mondi
2020-07-17 19:39 ` Laurent Pinchart
2020-07-23 20:57 ` Rob Herring
2020-07-17 13:28 ` [PATCH 05/13] dt-bindings: media: ov5640: Make bus-type mandatory Jacopo Mondi
2020-07-17 15:48 ` Fabio Estevam
2020-07-17 19:48 ` Laurent Pinchart
2020-07-20 19:45 ` Rob Herring
2020-07-17 13:28 ` [PATCH 06/13] dt-bindings: media: ov5640: Require ep properties Jacopo Mondi
2020-07-17 19:50 ` Laurent Pinchart
2020-07-17 13:28 ` [PATCH 07/13] dt-bindings: media: ov5640: Remove clock-lanes Jacopo Mondi
2020-07-17 20:48 ` Laurent Pinchart
2020-07-20 19:47 ` Rob Herring
2020-07-17 13:28 ` [PATCH 08/13] dt-bindings: media: ov5640: Remove data-shift Jacopo Mondi
2020-07-17 20:57 ` Laurent Pinchart
2020-07-23 22:22 ` Sakari Ailus
2020-07-23 23:15 ` Laurent Pinchart
2020-07-25 21:18 ` Sakari Ailus [this message]
2020-07-25 21:31 ` Laurent Pinchart
2020-07-29 14:29 ` Sakari Ailus
2020-07-29 14:46 ` Laurent Pinchart
2020-07-30 16:22 ` Sakari Ailus
2020-07-30 16:32 ` Laurent Pinchart
2020-07-30 16:43 ` Sakari Ailus
2020-07-17 13:28 ` [PATCH 09/13] dt-bindings: media: ov5640: Add default for synch signals Jacopo Mondi
2020-07-17 20:59 ` Laurent Pinchart
2020-07-20 19:50 ` Rob Herring
2020-07-17 13:28 ` [PATCH 10/13] dt-bindings: media: ov5640: Demote DVP required properties Jacopo Mondi
2020-07-17 21:00 ` Laurent Pinchart
2020-07-17 13:28 ` [PATCH 11/13] media: i2c: ov5640: Initialize DVP polarities as default Jacopo Mondi
2020-07-17 21:02 ` Laurent Pinchart
2020-07-17 13:28 ` [PATCH 12/13] MAINTAINERS: ov5640: Add bindings file Jacopo Mondi
2020-07-17 21:03 ` Laurent Pinchart
2020-07-17 13:28 ` [PATCH 13/13] dt-bindings: media: ov5640: Add myself as co-maintainer Jacopo Mondi
2020-07-17 21:03 ` Laurent Pinchart
2020-07-17 19:31 ` [PATCH 00/13] dt-bindings: media: ov5640: Convert to json-schema Laurent Pinchart
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