Re: [PATCH v6 3/8] usb: dwc3: Add support for role-switch-default-mode binding

[Bryan O'Donoghue <pure.logic@nexus-software.ie>]

On 28/11/2019 05:09, John Stultz wrote:
> Support the new role-switch-default-mode binding for configuring
> the default role the controller assumes as when the usb role is
> USB_ROLE_NONE
> 
> This patch was split out from a larger patch originally by
> Yu Chen <chenyu56@huawei.com>
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> CC: ShuFan Lee <shufan_lee@richtek.com>
> Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
> Cc: Yu Chen <chenyu56@huawei.com>
> Cc: Felipe Balbi <balbi@kernel.org>
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
> Cc: Jun Li <lijun.kernel@gmail.com>
> Cc: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Jack Pham <jackp@codeaurora.org>
> Cc: linux-usb@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> Change-Id: Ic6e4df1109b350deaecdc69f667d49ce91d599f3
> ---
> v3: Split this patch out from addition of usb-role-switch
>      handling
> v5: Reworked to use string based role-switch-default-mode
> ---
>   drivers/usb/dwc3/core.h |  3 +++
>   drivers/usb/dwc3/drd.c  | 25 ++++++++++++++++++++++---
>   2 files changed, 25 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 6f19e9891767..3c879c9ab1aa 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -953,6 +953,8 @@ struct dwc3_scratchpad_array {
>    *		- USBPHY_INTERFACE_MODE_UTMI
>    *		- USBPHY_INTERFACE_MODE_UTMIW
>    * @role_sw: usb_role_switch handle
> + * @role_switch_default_mode: default operation mode of controller while
> + *			usb role is USB_ROLE_NONE.
>    * @usb2_phy: pointer to USB2 PHY
>    * @usb3_phy: pointer to USB3 PHY
>    * @usb2_generic_phy: pointer to USB2 PHY
> @@ -1087,6 +1089,7 @@ struct dwc3 {
>   	struct notifier_block	edev_nb;
>   	enum usb_phy_interface	hsphy_mode;
>   	struct usb_role_switch	*role_sw;
> +	enum usb_dr_mode	role_switch_default_mode;
>   
>   	u32			fladj;
>   	u32			irq_gadget;
> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
> index 3b57d2ddda93..865341facece 100644
> --- a/drivers/usb/dwc3/drd.c
> +++ b/drivers/usb/dwc3/drd.c
> @@ -491,7 +491,10 @@ static int dwc3_usb_role_switch_set(struct device *dev, enum usb_role role)
>   		mode = DWC3_GCTL_PRTCAP_DEVICE;
>   		break;
>   	default:
> -		mode = DWC3_GCTL_PRTCAP_DEVICE;
> +		if (dwc->role_switch_default_mode == USB_DR_MODE_HOST)
> +			mode = DWC3_GCTL_PRTCAP_HOST;
> +		else
> +			mode = DWC3_GCTL_PRTCAP_DEVICE;
>   		break;
>   	}
>   
> @@ -517,7 +520,10 @@ static enum usb_role dwc3_usb_role_switch_get(struct device *dev)
>   		role = dwc->current_otg_role;
>   		break;
>   	default:
> -		role = USB_ROLE_DEVICE;
> +		if (dwc->role_switch_default_mode == USB_DR_MODE_HOST)
> +			role = USB_ROLE_HOST;
> +		else
> +			role = USB_ROLE_DEVICE;
>   		break;
>   	}
>   	spin_unlock_irqrestore(&dwc->lock, flags);
> @@ -527,6 +533,19 @@ static enum usb_role dwc3_usb_role_switch_get(struct device *dev)
>   static int dwc3_setup_role_switch(struct dwc3 *dwc)
>   {
>   	struct usb_role_switch_desc dwc3_role_switch = {NULL};
> +	const char *str;
> +	u32 mode;
> +	int ret;
> +
> +	ret = device_property_read_string(dwc->dev, "role-switch-default-mode",
> +					  &str);
> +	if (ret >= 0  && !strncmp(str, "host", strlen("host"))) {
> +		dwc->role_switch_default_mode = USB_DR_MODE_HOST;
> +		mode = DWC3_GCTL_PRTCAP_HOST;
> +	} else {
> +		dwc->role_switch_default_mode = USB_DR_MODE_PERIPHERAL;
> +		mode = DWC3_GCTL_PRTCAP_DEVICE;
> +	}
>   
>   	dwc3_role_switch.fwnode = dev_fwnode(dwc->dev);
>   	dwc3_role_switch.set = dwc3_usb_role_switch_set;
> @@ -535,7 +554,7 @@ static int dwc3_setup_role_switch(struct dwc3 *dwc)
>   	if (IS_ERR(dwc->role_sw))
>   		return PTR_ERR(dwc->role_sw);
>   
> -	dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
> +	dwc3_set_mode(dwc, mode);
>   	return 0;
>   }
>   #else
> 

I've used this on a qcs404 - it works for me.

Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>