linux-kernel - Re: [PATCH v4 2/5] usb: dwc3: host: Add suspend

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Message-ID: <X9K8hmAgzoWyMS9q@google.com>
Date:   Thu, 10 Dec 2020 16:25:42 -0800
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Sandeep Maheswaram <sanm@...eaurora.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Felipe Balbi <balbi@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Manu Gautam <mgautam@...eaurora.org>
Subject: Re: [PATCH v4 2/5] usb: dwc3: host: Add suspend_quirk for dwc3 host

On Wed, Oct 28, 2020 at 02:08:00AM +0530, Sandeep Maheswaram wrote:
> Adding suspend quirk function for dwc3 host which will be called
> during xhci suspend.
> Setting hs_phy_mode, ss_phy_mode flags and phy mode during host suspend.
> 
> Signed-off-by: Sandeep Maheswaram <sanm@...eaurora.org>
> ---
>  drivers/usb/dwc3/host.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 51 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
> index e195176..db03db8 100644
> --- a/drivers/usb/dwc3/host.c
> +++ b/drivers/usb/dwc3/host.c
> @@ -11,6 +11,13 @@
>  #include <linux/platform_device.h>
>  
>  #include "core.h"
> +#include "../host/xhci.h"
> +#include "../host/xhci-plat.h"
> +int xhci_dwc3_suspend_quirk(struct usb_hcd *hcd);
> +
> +static const struct xhci_plat_priv xhci_plat_dwc3_xhci = {
> +	.suspend_quirk = xhci_dwc3_suspend_quirk,
> +};
>  
>  static int dwc3_host_get_irq(struct dwc3 *dwc)
>  {
> @@ -115,6 +122,13 @@ int dwc3_host_init(struct dwc3 *dwc)
>  		}
>  	}
>  
> +	ret = platform_device_add_data(xhci, &xhci_plat_dwc3_xhci,
> +			sizeof(struct xhci_plat_priv));
> +	if (ret) {
> +		dev_err(dwc->dev, "failed to add data to xHCI\n");
> +		goto err;
> +	}
> +
>  	ret = platform_device_add(xhci);
>  	if (ret) {
>  		dev_err(dwc->dev, "failed to register xHCI device\n");
> @@ -127,6 +141,43 @@ int dwc3_host_init(struct dwc3 *dwc)
>  	return ret;
>  }
>  
> +static void dwc3_set_phy_mode(struct usb_hcd *hcd)
> +{
> +
> +	int i, num_ports;
> +	u32 reg;
> +	unsigned int ss_phy_mode = 0;
> +	struct device *dev = hcd->self.controller;
> +	struct dwc3 *dwc = dev_get_drvdata(dev->parent);

nit: the use of 'dev' seems misleading here. By convention 'dev' refers
to the 'struct device' of the driver, here it refers to a child of that
device. It's probably not super-important, but 'dev' is also not realy
needed, you could omit it and change the assignment of 'dwc3' to:

	struct dwc3 *dwc = dev_get_drvdata(hcd->self.controller->parent);

> +	struct xhci_hcd	*xhci_hcd = hcd_to_xhci(hcd);
> +
> +	dwc->hs_phy_mode = 0;
> +
> +	reg = readl(&xhci_hcd->cap_regs->hcs_params1);
> +
> +	num_ports = HCS_MAX_PORTS(reg);
> +	for (i = 0; i < num_ports; i++) {
> +		reg = readl(&xhci_hcd->op_regs->port_status_base + i * 0x04);
> +		if (reg & PORT_PE) {
> +			if (DEV_HIGHSPEED(reg) || DEV_FULLSPEED(reg))
> +				dwc->hs_phy_mode |= PHY_MODE_USB_HOST_HS;
> +			else if (DEV_LOWSPEED(reg))
> +				dwc->hs_phy_mode |= PHY_MODE_USB_HOST_LS;
> +
> +			if (DEV_SUPERSPEED(reg))
> +				ss_phy_mode |= PHY_MODE_USB_HOST_SS;
> +		}
> +	}
> +	phy_set_mode(dwc->usb2_generic_phy, dwc->hs_phy_mode);
> +	phy_set_mode(dwc->usb3_generic_phy, ss_phy_mode);
> +}
> +
> +int xhci_dwc3_suspend_quirk(struct usb_hcd *hcd)
> +{
> +	dwc3_set_phy_mode(hcd);
> +	return 0;
> +}
> +
>  void dwc3_host_exit(struct dwc3 *dwc)
>  {
>  	platform_device_unregister(dwc->xhci);

Other than the nit:

Reviewed-by: Matthias Kaehlcke <mka@...omium.org>