linux-kernel - Re: [PATCH v17 4/5] usb: dwc3: qcom: Configure wakeup interrupts during suspend

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Message-ID: <Yo1XzhTTxzRiNN8O@google.com>
Date:   Tue, 24 May 2022 15:10:22 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Krishna Kurapati <quic_kriskura@...cinc.com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Felipe Balbi <balbi@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        Mathias Nyman <mathias.nyman@...el.com>,
        devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, quic_pkondeti@...cinc.com,
        quic_ppratap@...cinc.com, quic_vpulyala@...cinc.com,
        Sandeep Maheswaram <quic_c_sanm@...cinc.com>
Subject: Re: [PATCH v17 4/5] usb: dwc3: qcom: Configure wakeup interrupts
 during suspend

On Tue, May 24, 2022 at 03:43:47PM +0530, Krishna Kurapati wrote:
> From: Sandeep Maheswaram <quic_c_sanm@...cinc.com>
> 
> Configure DP/DM line interrupts based on the USB2 device attached to
> the root hub port. When HS/FS device is connected, configure the DP line
> as falling edge to detect both disconnect and remote wakeup scenarios. When
> LS device is connected, configure DM line as falling edge to detect both
> disconnect and remote wakeup. When no device is connected, configure both
> DP and DM lines as rising edge to detect HS/HS/LS device connect scenario.
> 
> Signed-off-by: Sandeep Maheswaram <quic_c_sanm@...cinc.com>
> Reviewed-by: Matthias Kaehlcke <mka@...omium.org>

With the addition of dwc3_qcom_update_usb2_speed() the patch has changed a
bit since my review, I'm generally on board with the direction this is going,
but please remove my R-B tag for now.

> Signed-off-by: Krishna Kurapati <quic_kriskura@...cinc.com>
> ---
>  drivers/usb/dwc3/dwc3-qcom.c | 74 ++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 65 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> index 7352124..5d5db62 100644
> --- a/drivers/usb/dwc3/dwc3-qcom.c
> +++ b/drivers/usb/dwc3/dwc3-qcom.c
> @@ -20,7 +20,8 @@
>  #include <linux/usb/of.h>
>  #include <linux/reset.h>
>  #include <linux/iopoll.h>
> -
> +#include <linux/usb/hcd.h>
> +#include <linux/usb.h>
>  #include "core.h"
>  
>  /* USB QSCRATCH Hardware registers */
> @@ -296,11 +297,37 @@ static void dwc3_qcom_interconnect_exit(struct dwc3_qcom *qcom)
>  	icc_put(qcom->icc_path_apps);
>  }
>  
> -static void dwc3_qcom_enable_wakeup_irq(int irq)
> +enum usb_device_speed dwc3_qcom_update_usb2_speed(struct dwc3_qcom *qcom)
> +{
> +	struct dwc3	*dwc = platform_get_drvdata(qcom->dwc3);
> +	struct usb_hcd	*hcd = platform_get_drvdata(dwc->xhci);
> +	struct usb_device *udev;
> +	enum usb_device_speed usb2_speed;

nit: dwc and hcd are indented to align, udev and usb2_speed not. Either align
the indentation or not, but don't be inconsistent. My vote goes for removing
the alignment.

> +
> +	/*
> +	 * It is possible to query the speed of all children of
> +	 * USB2.0 root hub via usb_hub_for_each_child(). DWC3 code
> +	 * currently supports only 1 port per controller. So
> +	 * this is sufficient.
> +	 */
> +	udev = usb_hub_find_child(hcd->self.root_hub, 1);
> +
> +	if (udev)
> +		usb2_speed = udev->speed;
> +	else
> +		usb2_speed = USB_SPEED_UNKNOWN;
> +
> +	return usb2_speed;

nit: you could get away without 'usb2_speed':

	if (!udev)
		return USB_SPEED_UNKNOWN;

	return udev->speed;