Hi Sakari, On Fri, Jun 09, 2023 at 09:44:18AM +0000, Sakari Ailus wrote: > Hi Tommaso, > > On Fri, Jun 09, 2023 at 11:41:16AM +0200, Tommaso Merciai wrote: > > Hi Sakari, > > Thanks for your feedback. > > > > On Fri, Jun 09, 2023 at 08:35:20AM +0000, Sakari Ailus wrote: > > > Hi Tommaso, > > > > > > On Thu, Jun 08, 2023 at 10:31:15AM +0200, Tommaso Merciai wrote: > > > > Add documentation of device tree in YAML schema for the ALVIUM > > > > Camera from Allied Vision Inc. > > > > > > > > References: > > > > - https://www.alliedvision.com/en/products/embedded-vision-solutions > > > > > > > > Signed-off-by: Tommaso Merciai <tomm.merciai@xxxxxxxxx> > > > > Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > > > --- > > > > Changes since v1: > > > > - Fixed build error as suggested by RHerring bot > > > > > > > > Changes since v2: > > > > - Fixed License as suggested by KKozlowski/CDooley > > > > - Removed rotation property as suggested by CDooley/LPinchart > > > > - Fixed example node name as suggested by CDooley > > > > - Fixed title as suggested by LPinchart > > > > - Fixed compatible name as suggested by LPinchart > > > > - Removed clock as suggested by LPinchart > > > > - Removed gpios not as suggested by LPinchart > > > > - Renamed property name streamon-delay into alliedvision,lp2hs-delay-us > > > > - Fixed vendor prefix, unit append as suggested by KKozlowski > > > > - Fixed data-lanes > > > > - Fixed blank space + example indentation (from 6 -> 4 space) as suggested by KKozlowski > > > > - Dropped status into example as suggested by KKozlowski > > > > - Added vcc-ext-in supply as suggested by LPinchart > > > > - Dropped pinctrl into example as suggested by LPinchart > > > > > > > > Changes since v3: > > > > - Fixed vcc-ext-in-supply description as suggested by LPinchart > > > > - Fixed alliedvision,lp2hs-delay-us description as suggested by LPinchart > > > > - Added maximum to alliedvision,lp2hs-delay-us as suggested by LPinchart > > > > - Collected Reviewed-by tag from LPinchart > > > > > > > > Changes since v4: > > > > - Fixed id as reported by RHerring bot and LPinchart > > > > - Add minimum into alliedvision,lp2hs-delay-us as suggested by CDooley > > > > - Tested using make dt_binding_check DT_SCHEMA_FILES=alliedvision,alvium-csi2.yaml > > > > > > > > .../media/i2c/alliedvision,alvium-csi2.yaml | 97 +++++++++++++++++++ > > > > 1 file changed, 97 insertions(+) > > > > create mode 100644 Documentation/devicetree/bindings/media/i2c/alliedvision,alvium-csi2.yaml > > > > > > > > diff --git a/Documentation/devicetree/bindings/media/i2c/alliedvision,alvium-csi2.yaml b/Documentation/devicetree/bindings/media/i2c/alliedvision,alvium-csi2.yaml > > > > new file mode 100644 > > > > index 000000000000..c771e5039641 > > > > --- /dev/null > > > > +++ b/Documentation/devicetree/bindings/media/i2c/alliedvision,alvium-csi2.yaml > > > > @@ -0,0 +1,97 @@ > > > > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause > > > > +%YAML 1.2 > > > > +--- > > > > +$id: http://devicetree.org/schemas/media/i2c/alliedvision,alvium-csi2.yaml# > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > > > + > > > > +title: Allied Vision Alvium Camera > > > > + > > > > +maintainers: > > > > + - Tommaso Merciai <tomm.merciai@xxxxxxxxx> > > > > + - Martin Hecht <martin.hecht@xxxxxxxx> > > > > + > > > > +allOf: > > > > + - $ref: /schemas/media/video-interface-devices.yaml# > > > > + > > > > +properties: > > > > + compatible: > > > > + const: alliedvision,alvium-csi2 > > > > + > > > > + reg: > > > > + maxItems: 1 > > > > + > > > > + vcc-ext-in-supply: > > > > + description: | > > > > + The regulator that supplies power to the VCC_EXT_IN pins. > > > > + > > > > + alliedvision,lp2hs-delay-us: > > > > + minimum: 1 > > > > + maximum: 150000 > > > > + description: | > > > > + Low power to high speed delay time. > > > > + > > > > + If the value is larger than 0, the camera forces a reset of all > > > > + D-PHY lanes for the duration specified by this property. All lanes > > > > + will transition to the low-power state and back to the high-speed > > > > + state after the delay. Otherwise the lanes will transition to and > > > > + remain in the high-speed state immediately after power on. > > > > + > > > > + This is meant to help CSI-2 receivers synchronizing their D-PHY > > > > + RX. > > > > > > Why do you need this? D-PHY TX is obviously controlled by the driver. > > > Explicit control of PHY initialisation is of course best option when > > > combined with some receivers, done via driver's pre_streamon and s_stream > > > callbacks. Can't your hardware do that? > > > > You mean calculate this time in some dynamical way and program this > > during pre_streamon or s_stream? > > > > If yes, unfortunately hw can't do this. > > This shouldn't be based on timing but rather progress of the bus > initialisation sequence. That's how it works on most sensors nowadays. Just to clarify, this is not a sensor: "The Alvium camera is shipped with sensor + isp in the same housing. The camera can be equipped with one out of various sensor and abstract the user from this. Camera is connected via MIPI CSI-2." > > The description is also lacking details on what delay this exactly is. What > is the bus state during that delay? Previously we have a brief thread with Laurent about the behaviour of this reg/property, I repost here: "Thanks to Martin Hecht I'm able to provide you a clearer description: Alvium normally delivers a continous clock even when it is not streaming. The purpose of this reg is force a DPhy reset for the period described by the us on the reg before it starts streaming. To be clear, with that value bigger than 0 the Alvium forces a dphy-reset on all lanes for that period. That means all lanes go up into low power state. This may help a csi2 rx ip to reset if that IP can't deal with a continous clock." Hope these infos can clarify. Let me know. Thanks, Tommaso > > -- > Regards, > > Sakari Ailus
