Re: [PATCH v6 5/8] dt-bindings: media: add TI DS90UB960 FPD-Link III Deserializer

Laurent Pinchart
2023-01-09T09:14:25Z

On Mon, Jan 09, 2023 at 10:30:13AM +0200, Tomi Valkeinen wrote:
> On 08/01/2023 05:23, Laurent Pinchart wrote:
> > Hi Tomi,
> >
> > Thank you for the patch.
> >
> > On Thu, Jan 05, 2023 at 04:03:04PM +0200, Tomi Valkeinen wrote:
> >> Add DT bindings for TI DS90UB960 FPD-Link III Deserializer.
> >>
> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> >> Reviewed-by: Rob Herring <robh@kernel.org>
> >> ---
> >> .../bindings/media/i2c/ti,ds90ub960.yaml | 402 ++++++++++++++++++
> >> 1 file changed, 402 insertions(+)
> >> create mode 100644 Documentation/devicetree/bindings/media/i2c/ti,ds90ub960.yaml
> >>
> >> diff --git a/Documentation/devicetree/bindings/media/i2c/ti,ds90ub960.yaml b/Documentation/devicetree/bindings/media/i2c/ti,ds90ub960.yaml
> >> new file mode 100644
> >> index 000000000000..664799ae55be
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/media/i2c/ti,ds90ub960.yaml
> >> @@ -0,0 +1,402 @@
> >> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >> +%YAML 1.2
> >> +---
> >> +$id: http://devicetree.org/schemas/media/i2c/ti,ds90ub960.yaml#
> >> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >> +
> >> +title: Texas Instruments DS90UB9XX Family FPD-Link Deserializer Hubs
> >> +
> >> +maintainers:
> >> + - Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> >> +
> >> +description:
> >> + The TI DS90UB9XX devices are FPD-Link video deserializers with I2C and GPIO
> >> + forwarding.
> >> +
> >> +properties:
> >> + compatible:
> >> + enum:
> >> + - ti,ds90ub960-q1
> >> + - ti,ds90ub9702-q1
> >> +
> >> + reg:
> >> + maxItems: 1
> >> +
> >> + clocks:
> >> + maxItems: 1
> >> + description:
> >> + Reference clock connected to the REFCLK pin.
> >> +
> >> + clock-names:
> >> + items:
> >> + - const: refclk
> >> +
> >> + powerdown-gpios:
> >> + maxItems: 1
> >> + description:
> >> + Specifier for the GPIO connected to the PDB pin.
> >> +
> >> + i2c-alias-pool:
> >> + $ref: /schemas/types.yaml#/definitions/uint16-array
> >> + description:
> >> + I2C alias pool is a pool of I2C addresses on the main I2C bus that can be
> >> + used to access the remote peripherals on the serializer's I2C bus. The
> >> + addresses must be available, not used by any other peripheral. Each
> >> + remote peripheral is assigned an alias from the pool, and transactions to
> >> + that address will be forwarded to the remote peripheral, with the address
> >> + translated to the remote peripheral's real address. This property is not
> >> + needed if there are no I2C addressable remote peripherals.
> >> +
> >> + links:
> >> + type: object
> >> + additionalProperties: false
> >> +
> >> + properties:
> >> + '#address-cells':
> >> + const: 1
> >> +
> >> + '#size-cells':
> >> + const: 0
> >> +
> >> + ti,manual-strobe:
> >> + type: boolean
> >> + description:
> >> + Enable manual strobe position and EQ level
> >> +
> >> + patternProperties:
> >> + '^link@[0-3]$':
> >> + type: object
> >> + additionalProperties: false
> >> + properties:
> >> + reg:
> >> + description: The link number
> >> + maxItems: 1
> >> +
> >> + i2c-alias:
> >> + description:
> >> + The I2C address used for the serializer. Transactions to this
> >> + address on the I2C bus where the deserializer resides are
> >> + forwarded to the serializer.
> >> +
> >> + ti,rx-mode:
> >> + $ref: /schemas/types.yaml#/definitions/uint32
> >> + enum:
> >> + - 0 # RAW10
> >> + - 1 # RAW12 HF
> >> + - 2 # RAW12 LF
> >> + - 3 # CSI2 SYNC
> >> + - 4 # CSI2 NON-SYNC
> >> + description:
> >> + FPD-Link Input Mode. This should reflect the hardware and the
> >> + default mode of the connected camera module.
> >
> > As the remote device may not be a camera, I'd write "of the connected
> > device" or "of the connected serializer".
>
> I was trying to include the sensor also in the "camera module", as the
> sensor's "normal" pixel cloud would affect RAW modes (HF/LF). Perhaps
> "connected device" covers this.
>
> >> +
> >> + ti,cdr-mode:
> >> + $ref: /schemas/types.yaml#/definitions/uint32
> >> + enum:
> >> + - 0 # FPD-Link III
> >> + - 1 # FPD-Link IV
> >> + description:
> >> + FPD-Link CDR Mode. This should reflect the hardware and the
> >> + default mode of the connected camera module.
> >> +
> >> + ti,strobe-pos:
> >> + $ref: /schemas/types.yaml#/definitions/int32
> >> + minimum: -13
> >> + maximum: 13
> >> + description: Manual strobe position
> >> +
> >> + ti,eq-level:
> >> + $ref: /schemas/types.yaml#/definitions/uint32
> >> + maximum: 14
> >> + description: Manual EQ level
> >> +
> >> + serializer:
> >> + type: object
> >> + description: FPD-Link Serializer node
> >> +
> >> + required:
> >> + - reg
> >> + - i2c-alias
> >> + - ti,rx-mode
> >> + - serializer
> >> +
> >> + ports:
> >> + $ref: /schemas/graph.yaml#/properties/ports
> >> +
> >> + properties:
> >> + port@0:
> >> + $ref: /schemas/graph.yaml#/$defs/port-base
> >> + unevaluatedProperties: false
> >> + description: FPD-Link input 0
> >> +
> >> + properties:
> >> + endpoint:
> >> + $ref: /schemas/media/video-interfaces.yaml#
> >> + unevaluatedProperties: false
> >> + description:
> >> + Endpoint for FPD-Link port. If the RX mode for this port is RAW,
> >> + hsync-active and vsync-active must be defined.
> >> +
> >> + port@1:
> >> + $ref: /schemas/graph.yaml#/$defs/port-base
> >> + unevaluatedProperties: false
> >> + description: FPD-Link input 1
> >> +
> >> + properties:
> >> + endpoint:
> >> + $ref: /schemas/media/video-interfaces.yaml#
> >> + unevaluatedProperties: false
> >> + description:
> >> + Endpoint for FPD-Link port. If the RX mode for this port is RAW,
> >> + hsync-active and vsync-active must be defined.
> >> +
> >> + port@2:
> >> + $ref: /schemas/graph.yaml#/$defs/port-base
> >> + unevaluatedProperties: false
> >> + description: FPD-Link input 2
> >> +
> >> + properties:
> >> + endpoint:
> >> + $ref: /schemas/media/video-interfaces.yaml#
> >> + unevaluatedProperties: false
> >> + description:
> >> + Endpoint for FPD-Link port. If the RX mode for this port is RAW,
> >> + hsync-active and vsync-active must be defined.
> >> +
> >> + port@3:
> >> + $ref: /schemas/graph.yaml#/$defs/port-base
> >> + unevaluatedProperties: false
> >> + description: FPD-Link input 3
> >> +
> >> + properties:
> >> + endpoint:
> >> + $ref: /schemas/media/video-interfaces.yaml#
> >> + unevaluatedProperties: false
> >> + description:
> >> + Endpoint for FPD-Link port. If the RX mode for this port is RAW,
> >> + hsync-active and vsync-active must be defined.
> >> +
> >> + port@4:
> >> + $ref: /schemas/graph.yaml#/$defs/port-base
> >> + unevaluatedProperties: false
> >> + description: CSI-2 Output 0
> >> +
> >> + properties:
> >> + endpoint:
> >> + $ref: /schemas/media/video-interfaces.yaml#
> >> + unevaluatedProperties: false
> >> +
> >> + properties:
> >> + data-lanes:
> >> + minItems: 1
> >> + maxItems: 4
> >> +
> >> + required:
> >> + - data-lanes
> >> +
> >> + port@5:
> >> + $ref: /schemas/graph.yaml#/$defs/port-base
> >> + unevaluatedProperties: false
> >> + description: CSI-2 Output 1
> >> +
> >> + properties:
> >> + endpoint:
> >> + $ref: /schemas/media/video-interfaces.yaml#
> >> + unevaluatedProperties: false
> >> +
> >> + properties:
> >> + data-lanes:
> >> + minItems: 1
> >> + maxItems: 4
> >> +
> >> + required:
> >> + - data-lanes
> >
> > I think you need
> >
> > required:
> > - port@0
> > - port@1
> > - port@2
> > - port@3
> > - port@4
> > - port@5
>
> Is that needed? I think often some of the ports are unused (e.g. the
> example in this yaml file). Is it customary to still require empty port
> nodes in the DT?

Ports are an intrinsic property of a device, they don't depend on the
device integration in the system. In this case, the UB960 has four
FPD-Link inputs and two CSI-2 outputs, that's a property of the chip.
They don't have to be connected to anything on the board, so endpooints
are optional.

--
Regards,

Laurent Pinchart