linux-kernel - Re: [PATCH 10/13] phy: qcom-qmp-combo: drop sc8280xp power-down delay

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Message-ID: <ce6370f9-962c-905b-5188-a9b6ff9e2fd3@linaro.org>
Date:   Tue, 11 Oct 2022 17:07:16 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Johan Hovold <johan+linaro@...nel.org>,
        Vinod Koul <vkoul@...nel.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 10/13] phy: qcom-qmp-combo: drop sc8280xp power-down delay

On 11/10/2022 16:14, Johan Hovold wrote:
> The SC8280XP combo PHY does not need a delay before starting the USB PHY
> (which is what the has_pwrdn_delay config option really controls) so
> drop the unnecessary delay.
> 
> Signed-off-by: Johan Hovold <johan+linaro@...nel.org>
> ---
>   drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 4 ----
>   1 file changed, 4 deletions(-)

Just an obvious question: 'does not need a delay' comes from your 
experience or from some vendor flag (in ACPI/DT/kernel/wherever)?

> 
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> index 84380852ba5b..a8e09333072e 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> @@ -1210,10 +1210,6 @@ static const struct qmp_phy_cfg sc8280xp_usb43dp_usb_cfg = {
>   	.start_ctrl		= SERDES_START | PCS_START,
>   	.pwrdn_ctrl		= SW_PWRDN,
>   	.phy_status		= PHYSTATUS,
> -
> -	.has_pwrdn_delay	= true,
> -	.pwrdn_delay_min	= POWER_DOWN_DELAY_US_MIN,
> -	.pwrdn_delay_max	= POWER_DOWN_DELAY_US_MAX,
>   };
>   
>   static const struct qmp_phy_cfg sc8280xp_usb43dp_dp_cfg = {

-- 
With best wishes
Dmitry