Re: [PATCH v2 2/8] dt-bindings: i2c: qcom,i2c-geni: Add support for selecting data transfer mode

Dmitry Baryshkov
2025-01-24T11:18:06Z

On Fri, Jan 24, 2025 at 04:23:03PM +0530, Viken Dadhaniya wrote:
> Data transfer mode is fixed by TrustZone (TZ), which currently restricts
> developers from modifying the transfer mode from the APPS side.
>
> Document the 'qcom,xfer-mode' properties to select the data transfer mode,
> either GPI DMA (Generic Packet Interface) or non-GPI mode (PIO/CPU DMA).
>
> I2C controller can operate in one of two modes based on the
> 'qcom,xfer-mode' property, and the firmware is loaded accordingly.

Is it possible to load the firmware after it being loaded by TZ? Is it
possible to change the mode at runtime too?

>
> Co-developed-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
> Signed-off-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
> Signed-off-by: Viken Dadhaniya <quic_vdadhani@quicinc.com>
> ---
>
> v1 -> v2:
>
> - Drop 'qcom,load-firmware' property and add 'firmware-name' property in
> qup common driver.
> - Update commit log.
>
> v1 Link: https://lore.kernel.org/linux-kernel/20241204150326.1470749-2-quic_vdadhani@quicinc.com/
> ---
> ---
> .../devicetree/bindings/i2c/qcom,i2c-geni-qcom.yaml | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/i2c/qcom,i2c-geni-qcom.yaml b/Documentation/devicetree/bindings/i2c/qcom,i2c-geni-qcom.yaml
> index 9f66a3bb1f80..68e4bf0c84d1 100644
> --- a/Documentation/devicetree/bindings/i2c/qcom,i2c-geni-qcom.yaml
> +++ b/Documentation/devicetree/bindings/i2c/qcom,i2c-geni-qcom.yaml
> @@ -66,6 +66,12 @@ properties:
> required-opps:
> maxItems: 1
>
> + qcom,xfer-mode:
> + description: Set the value to 1 for non-GPI (FIFO/CPU DMA) mode and 3 for GPI DMA mode.
> + The default mode is FIFO.
> + $ref: /schemas/types.yaml#/definitions/uint32
> + enum: [1, 3]
> +
> required:
> - compatible
> - interrupts
> @@ -142,5 +148,6 @@ examples:
> interconnect-names = "qup-core", "qup-config", "qup-memory";
> power-domains = <&rpmhpd SC7180_CX>;
> required-opps = <&rpmhpd_opp_low_svs>;
> + qcom,xfer-mode = <1>;

What does <1> mean? Please provide corresponding defines.

> };
> ...
> --
> 2.34.1
>

--
With best wishes
Dmitry