Re: [PATCH v5 5/5] phy: fsl-imx8mq-usb: keep PHY power domain runtime always-on for i.MX8MP

From: Frank Li <Frank.li@oss.nxp.com>
To: Xu Yang <xu.yang_2@oss.nxp.com>
Cc: Vinod Koul <vkoul@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Frank Li <Frank.Li@nxp.com>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>, Jun Li <jun.li@nxp.com>,
	linux-phy@lists.infradead.org, imx@lists.linux.dev,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Xu Yang <xu.yang_2@nxp.com>
Subject: Re: [PATCH v5 5/5] phy: fsl-imx8mq-usb: keep PHY power domain runtime always-on for i.MX8MP
Date: Tue, 30 Jun 2026 14:13:33 -0500	[thread overview]
Message-ID: <akQVXYu27qG-SobS@SMW015318> (raw)
In-Reply-To: <20260630-imx8mp-usb-phy-improvement-v5-5-25d616403844@nxp.com>

On Tue, Jun 30, 2026 at 06:11:32PM +0800, Xu Yang wrote:
> From: Xu Yang <xu.yang_2@nxp.com>
>
> On i.MX8MP, the USB PHY has a dedicated power domain that was previously
> never powered off at runtime. With the introduction of runtime PM support,
> the power domain will be powered off if the device is runtime suspended,
> which breaks USB wakeup functionality.
>
> To preserve wakeup functionality, mark the PHY power domain as runtime
> always-on for i.MX8MP platform. To limit the behavior to i.MX8MP, add a
> new imx95_usb_phy_ops for i.MX95 and introduce usb_phy_is_imx8mp() helper
> to identify i.MX8MP PHY instance.
>
> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
>
> ---
> Changes in v5:
>  - no changes
> Changes in v4:
>  - no changes
> Changes in v3:
>  - new patch
> ---
>  drivers/phy/freescale/phy-fsl-imx8mq-usb.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
> index 4949ec78d304..c9741b532663 100644
> --- a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
> +++ b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
> @@ -9,6 +9,7 @@
>  #include <linux/of.h>
>  #include <linux/phy/phy.h>
>  #include <linux/platform_device.h>
> +#include <linux/pm_domain.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/regmap.h>
> @@ -660,13 +661,20 @@ static const struct phy_ops imx8mp_usb_phy_ops = {
>  	.owner		= THIS_MODULE,
>  };
>
> +static const struct phy_ops imx95_usb_phy_ops = {
> +	.init		= imx8mp_usb_phy_init,
> +	.power_on	= imx8mq_phy_power_on,
> +	.power_off	= imx8mq_phy_power_off,
> +	.owner		= THIS_MODULE,
> +};
> +
>  static const struct of_device_id imx8mq_usb_phy_of_match[] = {
>  	{.compatible = "fsl,imx8mq-usb-phy",
>  	 .data = &imx8mq_usb_phy_ops,},
>  	{.compatible = "fsl,imx8mp-usb-phy",
>  	 .data = &imx8mp_usb_phy_ops,},
>  	{.compatible = "fsl,imx95-usb-phy",
> -	 .data = &imx8mp_usb_phy_ops,},
> +	 .data = &imx95_usb_phy_ops,},
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(of, imx8mq_usb_phy_of_match);
> @@ -679,6 +687,11 @@ static const struct regmap_config imx_cr_regmap_config = {
>  	.max_register = 0x7,
>  };
>
> +static bool usb_phy_is_imx8mp(const void *data)
> +{
> +	return data == &imx8mp_usb_phy_ops;
> +}
> +

It is not good direct use drvdata as it.

Can you add new drvdata

drvdata
{
	phy_ops ops;
	bool always_on;
}

in follow probe check

if (always_on)
	...

it is more extendable in future.

Frank
>  static int imx8mq_usb_phy_probe(struct platform_device *pdev)
>  {
>  	struct phy_provider *phy_provider;
> @@ -721,6 +734,9 @@ static int imx8mq_usb_phy_probe(struct platform_device *pdev)
>  	if (!phy_ops)
>  		return -EINVAL;
>
> +	if (usb_phy_is_imx8mp(phy_ops))
> +		dev_pm_genpd_rpm_always_on(dev, true);
> +
>  	imx_phy->phy = devm_phy_create(dev, NULL, phy_ops);
>  	if (IS_ERR(imx_phy->phy))
>  		return PTR_ERR(imx_phy->phy);
>
> --
> 2.34.1
>
>