[v6,RESEND,0/2] Add support for ANX7688

(resending patchset with Rb tags)
ANX7688 is a typec port controller that also converts HDMI to DP.
It is found on Acer Chromebook R13 (elm) and on Pine64 PinePhone.

On Acer Chromebook R13 (elm), the device is powered-up and controller by the
Embedded Controller. Therefore its operation is transparent
to the SoC. It is used in elm only as a display bridge driver.
The bridge driver only reads some values using i2c and use them to
implement the mode_fixup cb.

On v5 we added the full dt-binding of the generic Analogix anx7688 device.
The problem is that for elm, most of the fields are not needed since
the anx7688 sits behind the EC. After a discussion on v5 (see [1])
we decided to go back to the original approach and send the dt binding
as specific to the elm. So in this version we rename the device to cros_ec_anx7688
and use the compatible 'google,cros-ec-anx7688'.

[1] https://patchwork.kernel.org/project/dri-devel/patch/20210305124351.15079-3-dafna.hirschfeld@collabora.com/

Changes since v5:
* treat the device as a specific combination of an ANX7688 behind the EC and
call it 'cros-ec-anx7688'

Changes since v4:
In v4 of this set, the device was added as an 'mfd' device
and an additional 'bridge' device for the HDMI-DP conversion, see [2].

[2] https://lkml.org/lkml/2020/3/18/64

Dafna Hirschfeld (1):
  dt-bindings: display: add google,cros-ec-anx7688.yaml

Enric Balletbo i Serra (1):
  drm/bridge: Add ChromeOS EC ANX7688 bridge driver support

 .../bridge/google,cros-ec-anx7688.yaml        |  82 ++++++++
 drivers/gpu/drm/bridge/Kconfig                |  12 ++
 drivers/gpu/drm/bridge/Makefile               |   1 +
 drivers/gpu/drm/bridge/cros-ec-anx7688.c      | 191 ++++++++++++++++++
 4 files changed, 286 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/google,cros-ec-anx7688.yaml
 create mode 100644 drivers/gpu/drm/bridge/cros-ec-anx7688.c

Series applied to drm-misc-next.

https://cgit.freedesktop.org/drm/drm-misc/commit/?id=b67f7599c90ae36a5174826132f7690fa13d462c

On Tue, 18 May 2021 at 16:19, Dafna Hirschfeld
<dafna.hirschfeld@collabora.com> wrote:
>
> ChromeOS EC ANX7688 is a display bridge that converts HDMI 2.0 to
> DisplayPort 1.3 Ultra-HDi (4096x2160p60). It is an Analogix ANX7688 chip
> which is connected to and operated by the ChromeOS Embedded Controller
> (See google,cros-ec.yaml). It is accessed using I2C tunneling through
> the EC and therefore its node should be a child of an EC I2C tunnel node
> (See google,cros-ec-i2c-tunnel.yaml).
>
> ChromOS EC ANX7688 is found on Acer Chromebook R13 (elm)
>
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> ---
>  .../bridge/google,cros-ec-anx7688.yaml        | 82 +++++++++++++++++++
>  1 file changed, 82 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/google,cros-ec-anx7688.yaml
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/google,cros-ec-anx7688.yaml b/Documentation/devicetree/bindings/display/bridge/google,cros-ec-anx7688.yaml
> new file mode 100644
> index 000000000000..9f7cc6b757cb
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/google,cros-ec-anx7688.yaml
> @@ -0,0 +1,82 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/bridge/google,cros-ec-anx7688.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ChromeOS EC ANX7688 HDMI to DP Converter through Type-C Port
> +
> +maintainers:
> +  - Nicolas Boichat <drinkcat@chromium.org>
> +  - Enric Balletbo i Serra <enric.balletbo@collabora.com>
> +
> +description: |
> +  ChromeOS EC ANX7688 is a display bridge that converts HDMI 2.0 to
> +  DisplayPort 1.3 Ultra-HDi (4096x2160p60). It is an Analogix ANX7688 chip
> +  which is connected to and operated by the ChromeOS Embedded Controller
> +  (See google,cros-ec.yaml). It is accessed using I2C tunneling through
> +  the EC and therefore its node should be a child of an EC I2C tunnel node
> +  (See google,cros-ec-i2c-tunnel.yaml).
> +
> +properties:
> +  compatible:
> +    const: google,cros-ec-anx7688
> +
> +  reg:
> +    maxItems: 1
> +    description: I2C address of the device.
> +
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description: Video port for HDMI input.
> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description: USB Type-c connector.
> +
> +    required:
> +      - port@0
> +      - port@1
> +
> +required:
> +  - compatible
> +  - reg
> +  - ports
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    i2c_tunnel_b: i2c-tunnel1 {
> +        compatible = "google,cros-ec-i2c-tunnel";
> +        google,remote-bus = <1>;
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        anx7688: anx7688@2c {
> +            compatible = "google,cros-ec-anx7688";
> +            reg = <0x2c>;
> +
> +            ports {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +                port@0 {
> +                    reg = <0>;
> +                    anx7688_in: endpoint {
> +                        remote-endpoint = <&hdmi0_out>;
> +                    };
> +                };
> +                port@1 {
> +                    reg = <1>;
> +                    anx7688_out: endpoint {
> +                        remote-endpoint = <&typec_connector>;
> +                    };
> +                };
> +            };
> +        };
> +    };
> +
> --
> 2.17.1
>