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Once the clock is stable, > ref_clk_en can be asserted. For lower power states where the reference > clock to the PHY is disabled, ref_clk_en should also be de-asserted. > > Move the ref_clk_en bit manipulation into imx95_pcie_enable_ref_clk() > to ensure the reference clock stabilizes before ref_clk_en is asserted > and before the PHY reset is de-asserted. This aligns with the timing > requirements specified in the PHY documentation. > > Fixes: d8574ce57d76 ("PCI: imx6: Add external reference clock input mode support") > Cc: > Signed-off-by: Richard Zhu > --- Reviewed-by: Frank Li > drivers/pci/controller/dwc/pci-imx6.c | 28 +++++++++++++++++++++------ > 1 file changed, 22 insertions(+), 6 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c > index 66e760015c92..c4b079c93648 100644 > --- a/drivers/pci/controller/dwc/pci-imx6.c > +++ b/drivers/pci/controller/dwc/pci-imx6.c > @@ -270,8 +270,6 @@ static int imx95_pcie_init_pre_reset(struct imx_pcie *imx_pcie) > > static int imx95_pcie_init_phy(struct imx_pcie *imx_pcie) > { > - bool ext = imx_pcie->enable_ext_refclk; > - > /* > * ERR051624: The Controller Without Vaux Cannot Exit L23 Ready > * Through Beacon or PERST# De-assertion > @@ -290,10 +288,6 @@ static int imx95_pcie_init_phy(struct imx_pcie *imx_pcie) > IMX95_PCIE_PHY_CR_PARA_SEL, > IMX95_PCIE_PHY_CR_PARA_SEL); > > - regmap_update_bits(imx_pcie->iomuxc_gpr, IMX95_PCIE_SS_RW_REG_0, > - IMX95_PCIE_REF_CLKEN, > - ext ? 0 : IMX95_PCIE_REF_CLKEN); > - > return 0; > } > > @@ -742,7 +736,29 @@ static void imx95_pcie_clkreq_override(struct imx_pcie *imx_pcie, bool enable) > > static int imx95_pcie_enable_ref_clk(struct imx_pcie *imx_pcie, bool enable) > { > + bool ext = imx_pcie->enable_ext_refclk; > + > imx95_pcie_clkreq_override(imx_pcie, enable); > + /* > + * The ref_clk_en signal must remain de-asserted until the > + * reference clock is running at appropriate frequency, at which > + * point this bit can be asserted. For lower power states where > + * the reference clock to the PHY is disabled, it may also be > + * de-asserted. > + * +------------------- -+--------+----------------+ > + * | External clock mode | Enable | PCIE_REF_CLKEN | > + * +---------------------+--------+----------------+ > + * | TRUE | X | 1b'0 | > + * +---------------------+--------+----------------+ > + * | FALSE | TRUE | 1b'1 | > + * +---------------------+--------+----------------+ > + * | FALSE | FALSE | 1b'0 | > + * +---------------------+--------+----------------+ > + */ > + regmap_update_bits(imx_pcie->iomuxc_gpr, IMX95_PCIE_SS_RW_REG_0, > + IMX95_PCIE_REF_CLKEN, > + ext || !enable ? 0 : IMX95_PCIE_REF_CLKEN); > + > return 0; > } > > -- > 2.37.1 >