by Luis de Oliveira

[permalink] [raw]

Subject: Re: [V2, 4/5] Documentation: dt-bindings: Document bindings for DW MIPI CSI-2 Host

On 20-Sep-18 14:24, Laurent Pinchart wrote:
> Hi Luis,
>
> Thank you for the patch.
>

Hi Laurent, thank you for your review.
My answers inline.

> On Thursday, 20 September 2018 14:16:42 EEST Luis Oliveira wrote:
>> Add bindings for Synopsys DesignWare MIPI CSI-2 host.
>>
>> Signed-off-by: Luis Oliveira <[email protected]>
>> ---
>> Changelog
>> v2:
>> - no changes
>>
>> .../devicetree/bindings/media/snps,dw-csi-plat.txt | 74 +++++++++++++++++++
>> 1 file changed, 74 insertions(+)
>> create mode 100644
>> Documentation/devicetree/bindings/media/snps,dw-csi-plat.txt
>>
>> diff --git a/Documentation/devicetree/bindings/media/snps,dw-csi-plat.txt
>> b/Documentation/devicetree/bindings/media/snps,dw-csi-plat.txt new file
>> mode 100644
>> index 0000000..028f5eb
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/media/snps,dw-csi-plat.txt
>> @@ -0,0 +1,74 @@
>> +Synopsys DesignWare CSI-2 Host controller
>> +
>> +Description
>> +-----------
>> +
>> +This HW block is used to receive image coming from an MIPI CSI-2 compatible
>> +camera.
>> +
>> +Required properties:
>> +- compatible: shall be "snps,dw-csi-plat"
>> +- reg : physical base address and size of the device memory mapped
>> + registers;
>> +- interrupts : CSI-2 Host interrupt
>> +- snps,output-type : Core output to be used (IPI-> 0 or IDI->1 or BOTH-
>> 2)
>> These
>> + values choose which of the Core outputs will be used, it
>> + can be Image Data Interface or Image Pixel Interface.
>> +- phys : List of one PHY specifier (as defined in
>> + Documentation/devicetree/bindings/phy/phy-bindings.txt).
>> + This PHY is a MIPI DPHY working in RX mode.
>> +- resets : Reference to a reset controller (optional)
>> +
>> +Optional properties(if in IPI mode):
>> +- snps,ipi-mode : Mode to be used when in IPI(Camera -> 0 or Controller -
>>
>> 1)
>> + This property defines if the controller will use the video
>> + timings available
>> + in the video stream or if it will use pre-defined ones.
>
> How does one select this ?
>

This is a hardware setting for timings in IPI (Image Pixel Interface - Synopsys
specific interface), default is Controller mode - 1.

This can be selected in the DT or after by the driver.

>> +- snps,ipi-color-mode : Bus depth to be used in IPI (48 bits -> 0 or 16
>> bits -> 1)
>> + This property defines the width of the IPI bus.
>
> How about using the standard bus-width property in the endpoint of the output
> port ?
>

Here I think It makes sense, I will use your suggestion.

>> +- snps,ipi-auto-flush : Data auto-flush (1 -> Yes or 0 -> No). This
>> property defines
>> + if the data is automatically flushed in each vsync
>> or if
>> + this process is done manually
>
> This seems like a configuration option, not a hardware property. I don't think
> it belongs to DT.
>
I see your point,

>> +- snps,virtual-channel : Virtual channel where data is present when in IPI
>> mode. This
>> + property chooses the virtual channel which IPI will use to
>> + retrieve the video stream.
>
> The virtual channel doesn't belong to DT, it should be queried from the sensor
> at runtime (and when a sensor can send multiple data streams, that should even
> be configurable).
>

I will do that.

I made this properties for my tests with cameras, thinking of SoCs that have
fixed HW configurations. But I can remove all this fields from the DT because
all of them can be made after in the driver.

>> +The per-board settings:
>> + - port sub-node describing a single endpoint connected to the camera as
>> + described in video-interfaces.txt[1].
>
> You need to explicitly list all the ports for this device, with their number
> and function.
>

Ok.

>> +Example:
>> +
>> + csi2_1: csi2@3000 {
>> + compatible = "snps,dw-csi-plat";
>> + #address-cells = <1>;
>> + #size-cells = <0>;
>> + reg = < 0x03000 0x7FF>;
>> + interrupts = <2>;
>> + output-type = <2>;
>> + resets = <&dw_rst 1>;
>> + phys = <&mipi_dphy_rx1 0>;
>> + phy-names = "csi2-dphy";
>> +
>> + /* IPI optional Configurations */
>> + snps,ipi-mode = <0>;
>> + snps,ipi-color-mode = <0>;
>> + snps,ipi-auto-flush = <1>;
>> + snps,virtual-channel = <0>;
>> +
>> + /* CSI-2 per-board settings */
>> + port@1 {
>> + reg = <1>;
>> + csi1_ep1: endpoint {
>> + remote-endpoint = <&camera_1>;
>> + data-lanes = <1 2>;
>> + };
>> + };
>> + port@2 {
>> + csi1_ep2: endpoint {
>> + remote-endpoint = <&vif1_ep>;
>> + };
>> + };
>> + };
>> +
>> +
>
> Extra blank lines.

Thanks.
>

2018-09-21 14:37:48

Hi Rob,

On 12-Oct-18 17:45, Rob Herring wrote:
> On Thu, Sep 20, 2018 at 01:16:40PM +0200, Luis Oliveira wrote:
>> Add device-tree bindings documentation for SNPS DesignWare MIPI D-PHY in
>> RX mode.
>
> "dt-bindings: phy: ..." for the subject.
>
Yes, you are right.

>>
>> Signed-off-by: Luis Oliveira <[email protected]>
>> ---
>> Changelog
>> v2:
>> - no changes
>>
>> .../devicetree/bindings/phy/snps,dphy-rx.txt | 36 ++++++++++++++++++++++
>> 1 file changed, 36 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/phy/snps,dphy-rx.txt
>>
>> diff --git a/Documentation/devicetree/bindings/phy/snps,dphy-rx.txt b/Documentation/devicetree/bindings/phy/snps,dphy-rx.txt
>> new file mode 100644
>> index 0000000..9079f4a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/phy/snps,dphy-rx.txt
>> @@ -0,0 +1,36 @@
>> +Synopsys DesignWare MIPI Rx D-PHY block details
>> +
>> +Description
>> +-----------
>> +
>> +The Synopsys MIPI D-PHY controller supports MIPI-DPHY in receiver mode.
>> +Please refer to phy-bindings.txt for more information.
>> +
>> +Required properties:
>> +- compatible : Shall be "snps,dphy-rx".
>> +- #phy-cells : Must be 1.
>> +- snps,dphy-frequency : Output frequency of the D-PHY.
>> +- snps,dphy-te-len : Size of the communication interface (8 bits->8 or 12bits->12).
>> +- reg : Physical base address and size of the device memory mapped
>> + registers;
>> +
>> +Optional properties:
>> +- snps,compat-mode : Compatibility mode control
>
> type? values?
>

I will remove this in V3.

>> +
>> +The per-board settings:
>> +- gpios : Synopsys testchip used as reference uses this to change setup
>> + configurations.
>
> Preferred to be named (e.g. foo-gpios). How many? What are their
> functions?
>

Ok, thanks for reviewing this.

>> +
>> +Example:
>> +
>> + mipi_dphy_rx1: dphy@3040 {
>> + compatible = "snps,dphy-rx";
>> + #phy-cells = <1>;
>> + snps,dphy-frequency = <300000>;
>> + snps,dphy-te-len = <12>;
>> + snps,compat-mode = <1>;
>> + reg = < 0x03040 0x20
>> + 0x08000 0x100
>> + 0x09000 0x100>;
>> + };
>> +
>> --
>> 2.9.3
>>