Hi Sakari, On Wed, Dec 02, 2020 at 11:20:31PM +0200, Sakari Ailus wrote: > Hi Jacopo, > > On Tue, Nov 10, 2020 at 06:40:33PM +0100, Jacopo Mondi wrote: > > From: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx> > > > > Document the DT bindings for the CSI2/CCP2 receiver peripheral (known as > > Unicam) on BCM283x SoCs. > > > > Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx> > > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > Signed-off-by: Jacopo Mondi <jacopo@xxxxxxxxxx> > > --- > > .../bindings/media/brcm,bcm2835-unicam.yaml | 155 ++++++++++++++++++ > > 1 file changed, 155 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml > > > > diff --git a/Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml b/Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml > > new file mode 100644 > > index 0000000000000..6ffc900e8ae8f > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml > > @@ -0,0 +1,155 @@ > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > +# Copyright (C) 2020 Raspberry Pi (Trading) Ltd. > > +%YAML 1.2 > > +--- > > +$id: http://devicetree.org/schemas/media/brcm,bcm2835-unicam.yaml# > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > + > > +title: Broadcom BCM283x Camera Interface (Unicam) > > + > > +maintainers: > > + - Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx> > > + - Raspberry Pi kernel list <kernel-list@xxxxxxxxxxxxxxx> > > + > > +description: > > + The Unicam block on BCM283x SoCs is the receiver for either CSI-2 or CCP2 > > + data from image sensors or similar devices. > > + > > + The main platform using this SoC is the Raspberry Pi family of boards. On the > > + Pi the VideoCore firmware can also control this hardware block, and driving > > + it from two different processors will cause issues. To avoid this, the > > + firmware checks the device tree configuration during boot. If it finds device > > + tree nodes whose name starts with "csi" then it will stop the firmware > > + accessing the block, and it can then safely be used via the device tree > > + binding. > > + > > +properties: > > + compatible: > > + const: brcm,bcm2835-unicam > > The compatible string doesn't quite match with the title. Which SoCs are > supported? > Afaict bcm2835 and bcm2711. There might be more I'm not aware of. There should be no distinction between then, but Dave knows more. Would a per-soc compatible work better or is a single brcm,unicam good enough to start with and we can add per-soc compatibles if there's any per-SoC difference that will need to be handled in future ? > > + > > + reg: > > + items: > > + - description: Main registers block > > + - description: Clock registers block > > + > > + interrupts: > > + maxItems: 1 > > + > > + clocks: > > + minItems: 1 > > + maxItems: 2 > > + > > + clock-names: > > + minItems: 1 > > + items: > > + - const: lp > > + - const: core > > + > > + power-domains: > > + maxItems: 1 > > + > > + brcm,num-data-lanes: > > + description: > > + The number of data lanes supported by this Unicam instance. It may be > > + larger than the number of data lanes routed on the board, as described by > > + the data-lanes property of the endpoint. > > + allOf: > > + - $ref: "/schemas/types.yaml#/definitions/uint32" > > + - enum: [1, 2, 4] > > Do you need this information besides how many lanes are connected? > > Does the number of lanes change even within the same model of SoC? Could > you use the compatible string to differentiate between them? > I had a similar question: https://patchwork.linuxtv.org/project/linux-media/patch/20200504092611.9798-5-laurent.pinchart@xxxxxxxxxxxxxxxx/#121079 I think the discussion ended with the fact that not all the available lanes in the IP might be routed to the connector, and that depends on the board. > > + > > + port: > > + type: object > > + description: > > + Input port node, as described in video-interfaces.txt. > > + > > + properties: > > + endpoint: > > + type: object > > + > > + properties: > > + clock-lanes: > > + items: > > + - const: 0 > > Please drop. There's nothing to tell software here. > Ack > > + > > + data-lanes: > > + description: > > + Lane reordering is not supported, items shall be in order, > > + starting at 1. > > + allOf: > > + - $ref: "/schemas/types.yaml#/definitions/uint32-array" > > + - maxItems: 1 > > + items: > > + minItems: 1 > > + maxItems: 4 > > + items: > > + - const: 1 > > + - const: 2 > > + - const: 3 > > + - const: 4 > > No need to specify items. > Actually here we might need to support [1, 2] and [1, 2, 3, 4]. I'll rebase on the converted video-interfaces to see it that helps > > + > > + lane-polarities: > > + description: > > + Lane inversion is not supported. If the property is specified, it > > + shall contain all 0's. > > Ditto. > Ack > > + allOf: > > + - $ref: "/schemas/types.yaml#/definitions/uint32-array" > > + - maxItems: 1 > > + items: > > + minItems: 2 > > + maxItems: 5 > > + items: > > + - const: 0 > > + - const: 0 > > + - const: 0 > > + - const: 0 > > + - const: 0 > > + > > + remote-endpoint: true > > + > > + required: > > + - data-lanes > > + - remote-endpoint > > + > > + additionalProperties: false > > + > > + required: > > + - endpoint > > + > > + additionalProperties: false > > + > > +required: > > + - compatible > > + - reg > > + - interrupts > > + - clocks > > + - clock-names > > + - power-domains > > + - brcm,num-data-lanes > > + - port > > + > > +additionalProperties: false > > + > > +examples: > > + - | > > + #include <dt-bindings/clock/bcm2835.h> > > + #include <dt-bindings/interrupt-controller/arm-gic.h> > > + #include <dt-bindings/power/raspberrypi-power.h> > > + > > + csi@7e801000 { > > + compatible = "brcm,bcm2835-unicam"; > > + reg = <0x7e801000 0x800>, > > + <0x7e802004 0x4>; > > + interrupts = <2 7>; > > + clocks = <&clocks BCM2835_CLOCK_CAM1>; > > + clock-names = "lp"; > > + power-domains = <&power RPI_POWER_DOMAIN_UNICAM1>; > > + brcm,num-data-lanes = <4>; > > + > > + port { > > + csi1_ep: endpoint { > > + remote-endpoint = <&imx219_0>; > > + data-lanes = <1 2>; > > + }; > > + }; > > + }; > > +... > > -- > Sakari Ailus
