[1/3] dt-bindings: usb: dwc2: add compatible "intel,socfpga-agilex-hsotg"

Add the compatible "intel,socfpga-agilex-hsotg" to the DWC2
implementation, because the Agilex DWC2 implementation does not support
clock gating.

Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
---
 Documentation/devicetree/bindings/usb/dwc2.yaml | 1 +
 1 file changed, 1 insertion(+)

On 1/25/2022 8:18 PM, Dinh Nguyen wrote:
> The DWC2 IP on the Agilex platform does not support clock-gating.
> 
> Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>

Acked-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>

> ---
>   drivers/usb/dwc2/params.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
> index d300ae3d9274..1306f4ec788d 100644
> --- a/drivers/usb/dwc2/params.c
> +++ b/drivers/usb/dwc2/params.c
> @@ -82,6 +82,14 @@ static void dwc2_set_s3c6400_params(struct dwc2_hsotg *hsotg)
>   	p->phy_utmi_width = 8;
>   }
>   
> +static void dwc2_set_socfpga_agilex_params(struct dwc2_hsotg *hsotg)
> +{
> +	struct dwc2_core_params *p = &hsotg->params;
> +
> +	p->power_down = DWC2_POWER_DOWN_PARAM_NONE;
> +	p->no_clock_gating = true;
> +}
> +
>   static void dwc2_set_rk_params(struct dwc2_hsotg *hsotg)
>   {
>   	struct dwc2_core_params *p = &hsotg->params;
> @@ -239,6 +247,8 @@ const struct of_device_id dwc2_of_match_table[] = {
>   	  .data = dwc2_set_stm32mp15_fsotg_params },
>   	{ .compatible = "st,stm32mp15-hsotg",
>   	  .data = dwc2_set_stm32mp15_hsotg_params },
> +	{ .compatible = "intel,socfpga-agilex-hsotg",
> +	  .data = dwc2_set_socfpga_agilex_params },
>   	{},
>   };
>   MODULE_DEVICE_TABLE(of, dwc2_of_match_table);

On Tue, 25 Jan 2022 10:18:19 -0600, Dinh Nguyen wrote:
> Add the compatible "intel,socfpga-agilex-hsotg" to the DWC2
> implementation, because the Agilex DWC2 implementation does not support
> clock gating.
> 
> Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
> ---
>  Documentation/devicetree/bindings/usb/dwc2.yaml | 1 +
>  1 file changed, 1 insertion(+)
> 

Acked-by: Rob Herring <robh@kernel.org>

On Tue, Jan 25, 2022 at 10:18:21AM -0600, Dinh Nguyen wrote:
> The DWC2 USB controller on the Agilex platform does not support clock
> gating, so use the chip specific "intel,socfpga-agilex-hsotg"
> compatible.
> 
> Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
> ---
>  arch/arm64/boot/dts/intel/socfpga_agilex.dtsi | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/intel/socfpga_agilex.dtsi b/arch/arm64/boot/dts/intel/socfpga_agilex.dtsi
> index 0dd2d2ee765a..f4270cf18996 100644
> --- a/arch/arm64/boot/dts/intel/socfpga_agilex.dtsi
> +++ b/arch/arm64/boot/dts/intel/socfpga_agilex.dtsi
> @@ -502,7 +502,7 @@ uart1: serial@ffc02100 {
>  		};
>  
>  		usb0: usb@ffb00000 {
> -			compatible = "snps,dwc2";
> +			compatible = "intel,socfpga-agilex-hsotg", "snps,dwc2";

In the same patchset you sent a bindings change which is contradictory
to this DTS change.

This is wrong here and dtbs_check will complain.

On Tue, Jan 25, 2022 at 10:18:19AM -0600, Dinh Nguyen wrote:
> Add the compatible "intel,socfpga-agilex-hsotg" to the DWC2
> implementation, because the Agilex DWC2 implementation does not support
> clock gating.
> 
> Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
> ---
>  Documentation/devicetree/bindings/usb/dwc2.yaml | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/dwc2.yaml b/Documentation/devicetree/bindings/usb/dwc2.yaml
> index f00867ebc147..481aaa09f3f2 100644
> --- a/Documentation/devicetree/bindings/usb/dwc2.yaml
> +++ b/Documentation/devicetree/bindings/usb/dwc2.yaml
> @@ -53,6 +53,7 @@ properties:
>            - const: st,stm32mp15-hsotg
>            - const: snps,dwc2
>        - const: samsung,s3c6400-hsotg
> +      - const: intel,socfpga-agilex-hsotg

This is confusing and wrong. Now the intel,socfpga-agilex-hsotg is
mentioned twice - with and without snps,dwc2. The DTS change in this
patchset added usage with snps,dwc2. The commit msg says it's
different, but is the difference incompatible?

Please clarify the AgileX HSOTG - is it compatible with snps,dwc2 or
not? Based on this the patch might need to be reverted (or changed).

Best regards,
Krzysztof