[v2] Add i.MX95 USB3.0 PHY alternate clock support

[PATCH v2 3/4] phy: fsl-imx8mq-usb: support alternate reference clock

Posted by Xu Yang 4 months ago

This phy supports both 24MHz and 100MHz clock inputs. By default it's
using XTAL 24MHz and the 100MHz clock is a alternate reference clock.
Add supports to use alternate reference clock in case 24MHz clock
can't work well.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>

---
Changes in v2:
 - add Rb tag
---
 drivers/phy/freescale/phy-fsl-imx8mq-usb.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
index b94f242420fc733cd75abef8ba1cd4f59ac18eb5..ad8a55012e42f2c15496955d00c6d5fd85c5beb2 100644
--- a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
+++ b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
@@ -16,6 +16,7 @@
 #define PHY_CTRL0_REF_SSP_EN		BIT(2)
 #define PHY_CTRL0_FSEL_MASK		GENMASK(10, 5)
 #define PHY_CTRL0_FSEL_24M		0x2a
+#define PHY_CTRL0_FSEL_100M		0x27
 
 #define PHY_CTRL1			0x4
 #define PHY_CTRL1_RESET			BIT(0)
@@ -108,6 +109,7 @@ struct tca_blk {
 struct imx8mq_usb_phy {
 	struct phy *phy;
 	struct clk *clk;
+	struct clk *alt_clk;
 	void __iomem *base;
 	struct regulator *vbus;
 	struct tca_blk *tca;
@@ -582,7 +584,8 @@ static int imx8mp_usb_phy_init(struct phy *phy)
 	/* USB3.0 PHY signal fsel for 24M ref */
 	value = readl(imx_phy->base + PHY_CTRL0);
 	value &= ~PHY_CTRL0_FSEL_MASK;
-	value |= FIELD_PREP(PHY_CTRL0_FSEL_MASK, PHY_CTRL0_FSEL_24M);
+	value |= FIELD_PREP(PHY_CTRL0_FSEL_MASK, imx_phy->alt_clk ?
+			    PHY_CTRL0_FSEL_100M : PHY_CTRL0_FSEL_24M);
 	writel(value, imx_phy->base + PHY_CTRL0);
 
 	/* Disable alt_clk_en and use internal MPLL clocks */
@@ -626,13 +629,24 @@ static int imx8mq_phy_power_on(struct phy *phy)
 	if (ret)
 		return ret;
 
-	return clk_prepare_enable(imx_phy->clk);
+	ret = clk_prepare_enable(imx_phy->clk);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(imx_phy->alt_clk);
+	if (ret) {
+		clk_disable_unprepare(imx_phy->clk);
+		return ret;
+	}
+
+	return ret;
 }
 
 static int imx8mq_phy_power_off(struct phy *phy)
 {
 	struct imx8mq_usb_phy *imx_phy = phy_get_drvdata(phy);
 
+	clk_disable_unprepare(imx_phy->alt_clk);
 	clk_disable_unprepare(imx_phy->clk);
 	regulator_disable(imx_phy->vbus);
 
@@ -681,6 +695,11 @@ static int imx8mq_usb_phy_probe(struct platform_device *pdev)
 		return PTR_ERR(imx_phy->clk);
 	}
 
+	imx_phy->alt_clk = devm_clk_get_optional(dev, "alt");
+	if (IS_ERR(imx_phy->alt_clk))
+		return dev_err_probe(dev, PTR_ERR(imx_phy->alt_clk),
+				    "Failed to get alt clk\n");
+
 	imx_phy->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(imx_phy->base))
 		return PTR_ERR(imx_phy->base);

-- 
2.34.1

Re: [PATCH v2 3/4] phy: fsl-imx8mq-usb: support alternate reference clock

Posted by Alexander Stein 3 months, 4 weeks ago

Am Freitag, 10. Oktober 2025, 13:01:12 CEST schrieb Xu Yang:
> This phy supports both 24MHz and 100MHz clock inputs. By default it's
> using XTAL 24MHz and the 100MHz clock is a alternate reference clock.
> Add supports to use alternate reference clock in case 24MHz clock
> can't work well.

This driver supports imx8mx and imx8mp as well. Do these SoC also support
the alternative clock?

Best regards
Alexander

> 
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
> 
> ---
> Changes in v2:
>  - add Rb tag
> ---
>  drivers/phy/freescale/phy-fsl-imx8mq-usb.c | 23 +++++++++++++++++++++--
>  1 file changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
> index b94f242420fc733cd75abef8ba1cd4f59ac18eb5..ad8a55012e42f2c15496955d00c6d5fd85c5beb2 100644
> --- a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
> +++ b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
> @@ -16,6 +16,7 @@
>  #define PHY_CTRL0_REF_SSP_EN		BIT(2)
>  #define PHY_CTRL0_FSEL_MASK		GENMASK(10, 5)
>  #define PHY_CTRL0_FSEL_24M		0x2a
> +#define PHY_CTRL0_FSEL_100M		0x27
>  
>  #define PHY_CTRL1			0x4
>  #define PHY_CTRL1_RESET			BIT(0)
> @@ -108,6 +109,7 @@ struct tca_blk {
>  struct imx8mq_usb_phy {
>  	struct phy *phy;
>  	struct clk *clk;
> +	struct clk *alt_clk;
>  	void __iomem *base;
>  	struct regulator *vbus;
>  	struct tca_blk *tca;
> @@ -582,7 +584,8 @@ static int imx8mp_usb_phy_init(struct phy *phy)
>  	/* USB3.0 PHY signal fsel for 24M ref */
>  	value = readl(imx_phy->base + PHY_CTRL0);
>  	value &= ~PHY_CTRL0_FSEL_MASK;
> -	value |= FIELD_PREP(PHY_CTRL0_FSEL_MASK, PHY_CTRL0_FSEL_24M);
> +	value |= FIELD_PREP(PHY_CTRL0_FSEL_MASK, imx_phy->alt_clk ?
> +			    PHY_CTRL0_FSEL_100M : PHY_CTRL0_FSEL_24M);
>  	writel(value, imx_phy->base + PHY_CTRL0);
>  
>  	/* Disable alt_clk_en and use internal MPLL clocks */
> @@ -626,13 +629,24 @@ static int imx8mq_phy_power_on(struct phy *phy)
>  	if (ret)
>  		return ret;
>  
> -	return clk_prepare_enable(imx_phy->clk);
> +	ret = clk_prepare_enable(imx_phy->clk);
> +	if (ret)
> +		return ret;
> +
> +	ret = clk_prepare_enable(imx_phy->alt_clk);
> +	if (ret) {
> +		clk_disable_unprepare(imx_phy->clk);
> +		return ret;
> +	}
> +
> +	return ret;
>  }
>  
>  static int imx8mq_phy_power_off(struct phy *phy)
>  {
>  	struct imx8mq_usb_phy *imx_phy = phy_get_drvdata(phy);
>  
> +	clk_disable_unprepare(imx_phy->alt_clk);
>  	clk_disable_unprepare(imx_phy->clk);
>  	regulator_disable(imx_phy->vbus);
>  
> @@ -681,6 +695,11 @@ static int imx8mq_usb_phy_probe(struct platform_device *pdev)
>  		return PTR_ERR(imx_phy->clk);
>  	}
>  
> +	imx_phy->alt_clk = devm_clk_get_optional(dev, "alt");
> +	if (IS_ERR(imx_phy->alt_clk))
> +		return dev_err_probe(dev, PTR_ERR(imx_phy->alt_clk),
> +				    "Failed to get alt clk\n");
> +
>  	imx_phy->base = devm_platform_ioremap_resource(pdev, 0);
>  	if (IS_ERR(imx_phy->base))
>  		return PTR_ERR(imx_phy->base);
> 
>

Re: [PATCH v2 3/4] phy: fsl-imx8mq-usb: support alternate reference clock

Posted by Xu Yang 3 months, 3 weeks ago

On Mon, Oct 13, 2025 at 07:58:12AM +0200, Alexander Stein wrote:
> Am Freitag, 10. Oktober 2025, 13:01:12 CEST schrieb Xu Yang:
> > This phy supports both 24MHz and 100MHz clock inputs. By default it's
> > using XTAL 24MHz and the 100MHz clock is a alternate reference clock.
> > Add supports to use alternate reference clock in case 24MHz clock
> > can't work well.
> 
> This driver supports imx8mx and imx8mp as well. Do these SoC also support
> the alternative clock?

imx8mp support the alternative clock too. Note that for imx8mp,
GPR_REG0.USB_PHY_REF_CLK_SEL needs also to be set if alternative clock is
necessary. However, it's not implemented for now. 

Thanks,
Xu Yang

> 
> Best regards
> Alexander
>