phy: fsl-imx8mq-usb: support alternate reference clock

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>
Link: https://patch.msgid.link/20251118071947.2504789-2-xu.yang_2@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
index b94f242420fc733cd75abef8ba1cd4f59ac18eb5..ad8a55012e42f2c15496955d00c6d5fd85c5beb2 100644 (file)
--- 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);