linux-kernel - Re: [PATCH 2/3] usb: dwc2: drd: add role-switch-default-node support

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Date:   Thu, 16 Dec 2021 10:26:06 +0000
From:   Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>
To:     Fabrice Gasnier <fabrice.gasnier@...s.st.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>
CC:     "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "amelie.delaunay@...s.st.com" <amelie.delaunay@...s.st.com>,
        "alexandre.torgue@...s.st.com" <alexandre.torgue@...s.st.com>
Subject: Re: [PATCH 2/3] usb: dwc2: drd: add role-switch-default-node support

On 12/6/2021 7:56 PM, Fabrice Gasnier wrote:
> When using usb-role-switch, while the usb role is not yet define
> (USB_ROLE_NONE), the user may want to configure the default mode to host
> or device.
> Use role-switch-default-mode for that purpose.
> 
> Signed-off-by: Amelie Delaunay <amelie.delaunay@...s.st.com>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@...s.st.com>

Acked-by: Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>
> ---
>   drivers/usb/dwc2/core.h |  3 +++
>   drivers/usb/dwc2/drd.c  | 13 +++++++++++++
>   2 files changed, 16 insertions(+)
> 
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index 37185eb..e2fe642 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -869,6 +869,8 @@ struct dwc2_hregs_backup {
>    *                      - USB_DR_MODE_HOST
>    *                      - USB_DR_MODE_OTG
>    * @role_sw:		usb_role_switch handle
> + * @role_sw_default_mode: default operation mode of controller while usb role
> + *			is USB_ROLE_NONE
>    * @hcd_enabled:	Host mode sub-driver initialization indicator.
>    * @gadget_enabled:	Peripheral mode sub-driver initialization indicator.
>    * @ll_hw_enabled:	Status of low-level hardware resources.
> @@ -1065,6 +1067,7 @@ struct dwc2_hsotg {
>   	enum usb_otg_state op_state;
>   	enum usb_dr_mode dr_mode;
>   	struct usb_role_switch *role_sw;
> +	enum usb_dr_mode role_sw_default_mode;
>   	unsigned int hcd_enabled:1;
>   	unsigned int gadget_enabled:1;
>   	unsigned int ll_hw_enabled:1;
> diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
> index aa6eb76..4f453ec 100644
> --- a/drivers/usb/dwc2/drd.c
> +++ b/drivers/usb/dwc2/drd.c
> @@ -24,6 +24,10 @@ static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
>   	gotgctl |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN;
>   	gotgctl |= GOTGCTL_DBNCE_FLTR_BYPASS;
>   	gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
> +	if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
> +		gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
> +	else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
> +		gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
>   	dwc2_writel(hsotg, gotgctl, GOTGCTL);
>   
>   	spin_unlock_irqrestore(&hsotg->lock, flags);
> @@ -105,6 +109,14 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
>   
>   	spin_lock_irqsave(&hsotg->lock, flags);
>   
> +	if (role == USB_ROLE_NONE) {
> +		/* default operation mode when usb role is USB_ROLE_NONE */
> +		if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
> +			role = USB_ROLE_HOST;
> +		else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
> +			role = USB_ROLE_DEVICE;
> +	}
> +
>   	if (role == USB_ROLE_HOST) {
>   		already = dwc2_ovr_avalid(hsotg, true);
>   	} else if (role == USB_ROLE_DEVICE) {
> @@ -146,6 +158,7 @@ int dwc2_drd_init(struct dwc2_hsotg *hsotg)
>   	if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
>   		return 0;
>   
> +	hsotg->role_sw_default_mode = usb_get_role_switch_default_mode(hsotg->dev);
>   	role_sw_desc.driver_data = hsotg;
>   	role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
>   	role_sw_desc.set = dwc2_drd_role_sw_set;