linux-kernel - Re: [PATCH v2 10/12] usb: dwc2: Add clock gating entering flow by system suspend

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Message-ID: <45e520b4-b078-09b9-7082-eb3a35aa10bb@gmail.com>
Date:   Tue, 13 Apr 2021 12:29:41 +0300
From:   Sergei Shtylyov <sergei.shtylyov@...il.com>
To:     Artur Petrosyan <Arthur.Petrosyan@...opsys.com>,
        Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     John Youn <John.Youn@...opsys.com>
Subject: Re: [PATCH v2 10/12] usb: dwc2: Add clock gating entering flow by
 system suspend

On 13.04.2021 10:37, Artur Petrosyan wrote:

> If not hibernation nor partial power down are supported,

    s/not/neither/?

> clock gating is used to save power.
> 
> Adds a new flow of entering clock gating when PC is
> suspended.
> 
> Signed-off-by: Artur Petrosyan <Arthur.Petrosyan@...opsys.com>
> ---
>   Changes in v2:
>   - None
> 
>   drivers/usb/dwc2/hcd.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
> index 31d6a1b87228..09dcd37b9ef8 100644
> --- a/drivers/usb/dwc2/hcd.c
> +++ b/drivers/usb/dwc2/hcd.c
> @@ -4372,6 +4372,15 @@ static int _dwc2_hcd_suspend(struct usb_hcd *hcd)
>   		break;
>   	case DWC2_POWER_DOWN_PARAM_HIBERNATION:
>   	case DWC2_POWER_DOWN_PARAM_NONE:
> +		/*
> +		 * If not hibernation nor partial power down are supported,

    s/not/neither/?

> +		 * clock gating is used to save power.
> +		 */
> +		dwc2_host_enter_clock_gating(hsotg);
> +
> +		/* After entering suspend, hardware is not accessible */
> +		clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
> +		break;
>   	default:
>   		goto skip_power_saving;
>   	}
MBR, Sergei