[RFC PATCH v2 3/7] media: dt-bindings: media: Add bindings for bcm2835-unicam
Jean-Michel Hautbois
jeanmichel.hautbois at ideasonboard.com
Sat Jan 22 00:38:59 PST 2022
Hi Laurent,
On 22/01/2022 00:27, Laurent Pinchart wrote:
> Hi Jean-Michel,
>
> Thank you for the patch.
>
> On Fri, Jan 21, 2022 at 09:18:06AM +0100, Jean-Michel Hautbois wrote:
>> Introduce the dt-bindinds documentation for bcm2835 CCP2/CSI2 camera
>
> s/bindinds/bindings/
>
> I'd mention "Unicam" somewhere here.
>
>> interface. Also add a MAINTAINERS entry for it.
Oh my, I tis not the right dts bindings patch, I mixed up my trees... :-/
Sorry for this I will send a v2.1 soon...
>>
>> Signed-off-by: Dave Stevenson <dave.stevenson at raspberrypi.com>
>> Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
>> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
>> ---
>> Dave: I assumed you were the maintainer for this file, as I based it on the
>> bcm2835-unicam.txt file. Are you happy to be added directly as the
>> maintainer, or should this be specified as "Raspberry Pi Kernel
>> Maintenance <kernel-list at raspberrypi.com>"
>> - in v2: multiple corrections to pass the bot checking as Rob kindly
>> told me.
>> ---
>> .../bindings/media/brcm,bcm2835-unicam.yaml | 103 ++++++++++++++++++
>> MAINTAINERS | 6 +
>> 2 files changed, 109 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 000000000000..1427514142cf
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml
>> @@ -0,0 +1,103 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%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 at raspberrypi.com>
>> +
>> +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 called csi0 or csi1 then
>> + it will stop the firmware accessing the block, and it can then
>> + safely be used via the device tree binding.
>
> As mentioned in the review of the DT integration, the nodes should
> ideally be called just "csi", not "csi0" and "csi1" (maybe Rob could
> confirm this ?). Dave, is there a way the firmware could be updated to
> also hand over control of the Unicam instances to Linux when a "csi"
> node is found, not just "csi0" or "csi1" ?
>
> Given that the node names are significant, they should be enforced in
> the YAML schema.
>
>> +
>> +properties:
>> + compatible:
>> + const: brcm,bcm2835-unicam
>> +
>> + reg:
>> + description:
>> + physical base address and length of the register sets for the device.
>
> This can be dropped.
>
>> + maxItems: 1
>
> There are two items in the example below. How does this validate ?
>
>> +
>> + interrupts:
>> + description: the IRQ line for this Unicam instance.
>
> This can be dropped.
>
>> + maxItems: 1
>> +
>> + clocks:
>> + description: |-
>> + list of clock specifiers, corresponding to entries in clock-names
>> + property.
>
> clocks:
> items:
> - description: The clock for ...
> - description: The clock for ...
>
> (with the two descriptions matching the LP and VPU clocks, I don't know
> what they are).
>
>> +
>> + clock-names:
>> + items:
>> + - const: lp
>> + - const: vpu
>> +
>> + port:
>> + $ref: /schemas/graph.yaml#/properties/port
>> +
>> +required:
>> + - compatible
>> + - reg
>> + - interrupts
>> + - clocks
>> + - clock-names
>> + - port
>> +
>> +additionalProperties: False
>> +
>> +examples:
>> + - |
>> + csi1: csi1 at 7e801000 {
>> + compatible = "brcm,bcm2835-unicam";
>> + reg = <0x7e801000 0x800>,
>> + <0x7e802004 0x4>;
>> + interrupts = <2 7>;
>
> Let's use the Pi 4 device tree as an example, as that's what we're
> upstreaming first.
>
>> + clocks = <&clocks BCM2835_CLOCK_CAM1>,
>
> This will fail to compile without a proper #include, did you get this to
> pass validation ?
>
>> + <&firmware_clocks 4>;
>> + clock-names = "lp", "vpu";
>> + port {
>> + csi1_ep: endpoint {
>> + remote-endpoint = <&tc358743_0>;
>> + data-lanes = <1 2>;
>> + };
>> + };
>> + };
>> +
>> + i2c0: i2c at 7e205000 {
>> + tc358743: csi-hdmi-bridge at 0f {
>> + compatible = "toshiba,tc358743";
>> + reg = <0x0f>;
>> + clocks = <&tc358743_clk>;
>> + clock-names = "refclk";
>> +
>> + tc358743_clk: bridge-clk {
>> + compatible = "fixed-clock";
>> + #clock-cells = <0>;
>> + clock-frequency = <27000000>;
>> + };
>> +
>> + port {
>> + tc358743_0: endpoint {
>> + remote-endpoint = <&csi1_ep>;
>> + clock-lanes = <0>;
>> + data-lanes = <1 2>;
>> + clock-noncontinuous;
>> + link-frequencies =
>> + /bits/ 64 <297000000>;
>> + };
>> + };
>> + };
>> + };
>
> I'd drop this node completely.
>
>> +...
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 33f75892f98e..07f238fd5ff9 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -3679,6 +3679,12 @@ F: Documentation/media/v4l-drivers/bcm2835-isp.rst
>> F: drivers/staging/vc04_services/bcm2835-isp
>> F: include/uapi/linux/bcm2835-isp.h
>>
>> +BROADCOM BCM2835 CAMERA DRIVER
>> +M: Raspberry Pi Kernel Maintenance <kernel-list at raspberrypi.com>
>> +L: linux-media at vger.kernel.org
>> +S: Maintained
>> +F: Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml
>> +
>> BROADCOM BCM47XX MIPS ARCHITECTURE
>> M: Hauke Mehrtens <hauke at hauke-m.de>
>> M: Rafał Miłecki <zajec5 at gmail.com>
>
More information about the linux-arm-kernel
mailing list