Re: [PATCH v6 04/10] PCI: imx6: Introduce SoC specific callbacks for controlling REFCLK

Manivannan Sadhasivam
2024-06-30T16:04:14Z

On Mon, Jun 17, 2024 at 04:16:40PM -0400, Frank Li wrote:
> Instead of using the switch case statement to enable/disable the reference
> clock handled by this driver itself, let's introduce a new callback
> set_ref_clk() and define it for platforms that require it. This simplifies

Should this be called 'enable_ref_clk' since the callback is supposed to enable
REFCLK?

> the code.
>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
> drivers/pci/controller/dwc/pci-imx6.c | 112 ++++++++++++++++------------------
> 1 file changed, 52 insertions(+), 60 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 47134e2dfecf2..ff9d0098294fa 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -103,6 +103,7 @@ struct imx_pcie_drvdata {
> const u32 mode_mask[IMX_PCIE_MAX_INSTANCES];
> const struct pci_epc_features *epc_features;
> int (*init_phy)(struct imx_pcie *pcie);
> + int (*set_ref_clk)(struct imx_pcie *pcie, bool enable);
> };
>
> struct imx_pcie {
> @@ -585,21 +586,19 @@ static int imx_pcie_attach_pd(struct device *dev)
> return 0;
> }
>
> -static int imx_pcie_enable_ref_clk(struct imx_pcie *imx_pcie)
> +static int imx6sx_pcie_set_ref_clk(struct imx_pcie *imx_pcie, bool enable)
> {
> - unsigned int offset;
> - int ret = 0;
> + regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX6SX_GPR12_PCIE_TEST_POWERDOWN,
> + enable ? 0 : IMX6SX_GPR12_PCIE_TEST_POWERDOWN);
>
> - switch (imx_pcie->drvdata->variant) {
> - case IMX6SX:
> - regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12,
> - IMX6SX_GPR12_PCIE_TEST_POWERDOWN, 0);
> - break;
> - case IMX6QP:
> - case IMX6Q:
> + return 0;
> +}
> +
> +static int imx6q_pcie_set_ref_clk(struct imx_pcie *imx_pcie, bool enable)
> +{
> + if (enable) {
> /* power up core phy and enable ref clock */
> - regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1,
> - IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18);
> + regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1, IMX6Q_GPR1_PCIE_TEST_PD, 0);
> /*
> * the async reset input need ref clock to sync internally,
> * when the ref clock comes after reset, internal synced
> @@ -608,54 +607,34 @@ static int imx_pcie_enable_ref_clk(struct imx_pcie *imx_pcie)
> */
> usleep_range(10, 100);
> regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1,
> - IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16);
> - break;
> - case IMX7D:
> - case IMX95:
> - case IMX95_EP:
> - break;
> - case IMX8MM:
> - case IMX8MM_EP:
> - case IMX8MQ:
> - case IMX8MQ_EP:
> - case IMX8MP:
> - case IMX8MP_EP:
> - offset = imx_pcie_grp_offset(imx_pcie);
> - /*
> - * Set the over ride low and enabled
> - * make sure that REF_CLK is turned on.
> - */
> - regmap_update_bits(imx_pcie->iomuxc_gpr, offset,
> - IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE,
> - 0);
> - regmap_update_bits(imx_pcie->iomuxc_gpr, offset,
> - IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
> - IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN);
> - break;
> + IMX6Q_GPR1_PCIE_REF_CLK_EN, IMX6Q_GPR1_PCIE_REF_CLK_EN);
> + } else {
> + regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1,
> + IMX6Q_GPR1_PCIE_REF_CLK_EN, 0);
> + regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1,
> + IMX6Q_GPR1_PCIE_TEST_PD, IMX6Q_GPR1_PCIE_TEST_PD);
> }
>
> - return ret;
> + return 0;
> }
>
> -static void imx_pcie_disable_ref_clk(struct imx_pcie *imx_pcie)
> +static int imx8mm_pcie_set_ref_clk(struct imx_pcie *imx_pcie, bool enable)
> {
> - switch (imx_pcie->drvdata->variant) {
> - case IMX6QP:
> - case IMX6Q:
> - regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1,
> - IMX6Q_GPR1_PCIE_REF_CLK_EN, 0);
> - regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1,
> - IMX6Q_GPR1_PCIE_TEST_PD,
> - IMX6Q_GPR1_PCIE_TEST_PD);
> - break;
> - case IMX7D:
> - regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12,
> - IMX7D_GPR12_PCIE_PHY_REFCLK_SEL,
> - IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
> - break;
> - default:
> - break;
> - }
> + int offset = imx_pcie_grp_offset(imx_pcie);
> +
> + /* Set the over ride low and enabled make sure that REF_CLK is turned on.*/

This comment provides no useful info. So please remove it.

> + regmap_update_bits(imx_pcie->iomuxc_gpr, offset, IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE,
> + enable ? 0 : IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE);
> + regmap_update_bits(imx_pcie->iomuxc_gpr, offset, IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
> + enable ? IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN : 0);
> + return 0;
> +}
> +
> +static int imx7d_pcie_set_ref_clk(struct imx_pcie *imx_pcie, bool enable)
> +{
> + regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX7D_GPR12_PCIE_PHY_REFCLK_SEL,
> + enable ? 0 : IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
> + return 0;

Previously imx6_pcie_enable_ref_clk() was bailing out for IMX7D. But now you are
explicitly enabling it. What is the reason?

- Mani

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