Re: [PATCH v7 04/10] PCI: imx6: Introduce SoC specific callbacks for controlling REFCLK

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Mon, Jul 08, 2024 at 01:08:08PM -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
> enable_ref_clk() and define it for platforms that require it. This
> simplifies the code.
> 
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 111 ++++++++++++++++------------------
>  1 file changed, 51 insertions(+), 60 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 47134e2dfecf2..dbcb70186036e 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 (*enable_ref_clk)(struct imx_pcie *pcie, bool enable);
>  };
>  
>  struct imx_pcie {
> @@ -585,21 +586,20 @@ 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_enable_ref_clk(struct imx_pcie *imx_pcie, bool enable)
>  {
> -	unsigned int offset;
> -	int ret = 0;
> +	if (enable)
> +		regmap_clear_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12,
> +				  IMX6SX_GPR12_PCIE_TEST_POWERDOWN);

Since all SoCs except IMX6Q/6QP doesn't have both enable/disable controls (which
is very weird btw), you can have separate enable/disable callbacks and just
populate the ones that require.

This way it becomes clear which SoC is supporting what. If you have a common
helper and just toggle based on a bool, then it becomes hard to follow.

- Mani

>  
> -	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_enable_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_clear_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1, IMX6Q_GPR1_PCIE_TEST_PD);
>  		/*
>  		 * the async reset input need ref clock to sync internally,
>  		 * when the ref clock comes after reset, internal synced
> @@ -607,55 +607,33 @@ static int imx_pcie_enable_ref_clk(struct imx_pcie *imx_pcie)
>  		 * add one ~10us delay here.
>  		 */
>  		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;
> +		regmap_set_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1, IMX6Q_GPR1_PCIE_REF_CLK_EN);
> +	} else {
> +		regmap_clear_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1, IMX6Q_GPR1_PCIE_REF_CLK_EN);
> +		regmap_set_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR1, 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_enable_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);
> +
> +	if (enable) {
> +		regmap_clear_bits(imx_pcie->iomuxc_gpr, offset, IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE);
> +		regmap_set_bits(imx_pcie->iomuxc_gpr, offset, IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN);
>  	}
> +
> +	return 0;
> +}
> +
> +static int imx7d_pcie_enable_ref_clk(struct imx_pcie *imx_pcie, bool enable)
> +{
> +	if (!enable)
> +		regmap_set_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12,
> +				IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
> +	return 0;
>  }
>  
>  static int imx_pcie_clk_enable(struct imx_pcie *imx_pcie)
> @@ -668,10 +646,12 @@ static int imx_pcie_clk_enable(struct imx_pcie *imx_pcie)
>  	if (ret)
>  		return ret;
>  
> -	ret = imx_pcie_enable_ref_clk(imx_pcie);
> -	if (ret) {
> -		dev_err(dev, "unable to enable pcie ref clock\n");
> -		goto err_ref_clk;
> +	if (imx_pcie->drvdata->enable_ref_clk) {
> +		ret = imx_pcie->drvdata->enable_ref_clk(imx_pcie, true);
> +		if (ret) {
> +			dev_err(dev, "Failed to enable PCIe REFCLK\n");
> +			goto err_ref_clk;
> +		}
>  	}
>  
>  	/* allow the clocks to stabilize */
> @@ -686,7 +666,8 @@ static int imx_pcie_clk_enable(struct imx_pcie *imx_pcie)
>  
>  static void imx_pcie_clk_disable(struct imx_pcie *imx_pcie)
>  {
> -	imx_pcie_disable_ref_clk(imx_pcie);
> +	if (imx_pcie->drvdata->enable_ref_clk)
> +		imx_pcie->drvdata->enable_ref_clk(imx_pcie, false);
>  	clk_bulk_disable_unprepare(imx_pcie->drvdata->clks_cnt, imx_pcie->clks);
>  }
>  
> @@ -1475,6 +1456,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.mode_off[0] = IOMUXC_GPR12,
>  		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  		.init_phy = imx_pcie_init_phy,
> +		.enable_ref_clk = imx6q_pcie_enable_ref_clk,
>  	},
>  	[IMX6SX] = {
>  		.variant = IMX6SX,
> @@ -1489,6 +1471,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.mode_off[0] = IOMUXC_GPR12,
>  		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  		.init_phy = imx6sx_pcie_init_phy,
> +		.enable_ref_clk = imx6sx_pcie_enable_ref_clk,
>  	},
>  	[IMX6QP] = {
>  		.variant = IMX6QP,
> @@ -1504,6 +1487,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.mode_off[0] = IOMUXC_GPR12,
>  		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  		.init_phy = imx_pcie_init_phy,
> +		.enable_ref_clk = imx6q_pcie_enable_ref_clk,
>  	},
>  	[IMX7D] = {
>  		.variant = IMX7D,
> @@ -1516,6 +1500,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.mode_off[0] = IOMUXC_GPR12,
>  		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  		.init_phy = imx7d_pcie_init_phy,
> +		.enable_ref_clk = imx7d_pcie_enable_ref_clk,
>  	},
>  	[IMX8MQ] = {
>  		.variant = IMX8MQ,
> @@ -1529,6 +1514,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.mode_off[1] = IOMUXC_GPR12,
>  		.mode_mask[1] = IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE,
>  		.init_phy = imx8mq_pcie_init_phy,
> +		.enable_ref_clk = imx8mm_pcie_enable_ref_clk,
>  	},
>  	[IMX8MM] = {
>  		.variant = IMX8MM,
> @@ -1540,6 +1526,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.clks_cnt = ARRAY_SIZE(imx8mm_clks),
>  		.mode_off[0] = IOMUXC_GPR12,
>  		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
> +		.enable_ref_clk = imx8mm_pcie_enable_ref_clk,
>  	},
>  	[IMX8MP] = {
>  		.variant = IMX8MP,
> @@ -1551,6 +1538,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.clks_cnt = ARRAY_SIZE(imx8mm_clks),
>  		.mode_off[0] = IOMUXC_GPR12,
>  		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
> +		.enable_ref_clk = imx8mm_pcie_enable_ref_clk,
>  	},
>  	[IMX95] = {
>  		.variant = IMX95,
> @@ -1577,6 +1565,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.mode_mask[1] = IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE,
>  		.epc_features = &imx8m_pcie_epc_features,
>  		.init_phy = imx8mq_pcie_init_phy,
> +		.enable_ref_clk = imx8mm_pcie_enable_ref_clk,
>  	},
>  	[IMX8MM_EP] = {
>  		.variant = IMX8MM_EP,
> @@ -1589,6 +1578,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.mode_off[0] = IOMUXC_GPR12,
>  		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  		.epc_features = &imx8m_pcie_epc_features,
> +		.enable_ref_clk = imx8mm_pcie_enable_ref_clk,
>  	},
>  	[IMX8MP_EP] = {
>  		.variant = IMX8MP_EP,
> @@ -1601,6 +1591,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  		.mode_off[0] = IOMUXC_GPR12,
>  		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
>  		.epc_features = &imx8m_pcie_epc_features,
> +		.enable_ref_clk = imx8mm_pcie_enable_ref_clk,
>  	},
>  	[IMX95_EP] = {
>  		.variant = IMX95_EP,
> 
> -- 
> 2.34.1
> 

-- 
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