Re: [PATCH v2 2/6] usb: phy: mxs: keep USBPHY2's clk always on

From: Peter Chen <peter.chen@kernel.org>
To: Xu Yang <xu.yang_2@nxp.com>
Cc: vkoul@kernel.org, kishon@kernel.org, robh@kernel.org,
	krzk+dt@kernel.org, conor+dt@kernel.org, shawnguo@kernel.org,
	s.hauer@pengutronix.de, kernel@pengutronix.de,
	festevam@gmail.com, gregkh@linuxfoundation.org,
	herve.codina@bootlin.com, linux-phy@lists.infradead.org,
	devicetree@vger.kernel.org, imx@lists.linux.dev,
	linux-arm-kernel@lists.infradead.org, linux-usb@vger.kernel.org,
	jun.li@nxp.com
Subject: Re: [PATCH v2 2/6] usb: phy: mxs: keep USBPHY2's clk always on
Date: Fri, 9 Aug 2024 09:36:42 +0800	[thread overview]
Message-ID: <20240809013642.GF2673490@nchen-desktop> (raw)
In-Reply-To: <20240726113207.3393247-2-xu.yang_2@nxp.com>

On 24-07-26 19:32:03, Xu Yang wrote:
> IP require keep USBPHY2's clk always on, so USBPHY2 (PLL7) power can be
> controlled by suspend signal. USB remote wakeup needs resume signal be
> sent out as soon as possible to match USB requirements.
> 
> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>

Reviewed-by: Peter Chen <peter.chen@kernel.org>
> 
> ---
> Changes in v2:
>  - modify commit message
>  - remove hardware_control_phy2_clk
> ---
>  drivers/usb/phy/phy-mxs-usb.c | 33 ++++++++++++++++++++++++++-------
>  1 file changed, 26 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/usb/phy/phy-mxs-usb.c b/drivers/usb/phy/phy-mxs-usb.c
> index d9d29f0b37de..e172af75f602 100644
> --- a/drivers/usb/phy/phy-mxs-usb.c
> +++ b/drivers/usb/phy/phy-mxs-usb.c
> @@ -150,6 +150,15 @@
>  #define MXS_PHY_TX_D_CAL_MIN			79
>  #define MXS_PHY_TX_D_CAL_MAX			119
>  
> +/*
> + * At imx6q/6sl/6sx, the PHY2's clock is controlled by hardware directly,
> + * eg, according to PHY's suspend status. In these PHYs, we only need to
> + * open the clock at the initialization and close it at its shutdown routine.
> + * These PHYs can send resume signal without software interfere if not
> + * gate clock.
> + */
> +#define MXS_PHY_HARDWARE_CONTROL_PHY2_CLK	BIT(4)
> +
>  struct mxs_phy_data {
>  	unsigned int flags;
>  };
> @@ -161,12 +170,14 @@ static const struct mxs_phy_data imx23_phy_data = {
>  static const struct mxs_phy_data imx6q_phy_data = {
>  	.flags = MXS_PHY_SENDING_SOF_TOO_FAST |
>  		MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS |
> -		MXS_PHY_NEED_IP_FIX,
> +		MXS_PHY_NEED_IP_FIX |
> +		MXS_PHY_HARDWARE_CONTROL_PHY2_CLK,
>  };
>  
>  static const struct mxs_phy_data imx6sl_phy_data = {
>  	.flags = MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS |
> -		MXS_PHY_NEED_IP_FIX,
> +		MXS_PHY_NEED_IP_FIX |
> +		MXS_PHY_HARDWARE_CONTROL_PHY2_CLK,
>  };
>  
>  static const struct mxs_phy_data vf610_phy_data = {
> @@ -175,7 +186,8 @@ static const struct mxs_phy_data vf610_phy_data = {
>  };
>  
>  static const struct mxs_phy_data imx6sx_phy_data = {
> -	.flags = MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS,
> +	.flags = MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS |
> +		MXS_PHY_HARDWARE_CONTROL_PHY2_CLK,
>  };
>  
>  static const struct mxs_phy_data imx6ul_phy_data = {
> @@ -518,12 +530,19 @@ static int mxs_phy_suspend(struct usb_phy *x, int suspend)
>  		}
>  		writel(BM_USBPHY_CTRL_CLKGATE,
>  		       x->io_priv + HW_USBPHY_CTRL_SET);
> -		clk_disable_unprepare(mxs_phy->clk);
> +		if (!(mxs_phy->port_id == 1 &&
> +			(mxs_phy->data->flags &
> +				MXS_PHY_HARDWARE_CONTROL_PHY2_CLK)))
> +			clk_disable_unprepare(mxs_phy->clk);
>  	} else {
>  		mxs_phy_clock_switch_delay();
> -		ret = clk_prepare_enable(mxs_phy->clk);
> -		if (ret)
> -			return ret;
> +		if (!(mxs_phy->port_id == 1 &&
> +			(mxs_phy->data->flags &
> +				MXS_PHY_HARDWARE_CONTROL_PHY2_CLK))) {
> +			ret = clk_prepare_enable(mxs_phy->clk);
> +			if (ret)
> +				return ret;
> +		}
>  		writel(BM_USBPHY_CTRL_CLKGATE,
>  		       x->io_priv + HW_USBPHY_CTRL_CLR);
>  		writel(0, x->io_priv + HW_USBPHY_PWD);
> -- 
> 2.34.1
>