Re: [PATCH] PCI: imx6: add regulator support

[Bjorn Helgaas]

On Thu, Jun 08, 2017 at 10:07:42AM +0200, Quentin Schulz wrote:
> Some boards might require to control a regulator to power the PCIe port.
> 
> This adds support for an optional regulator defined in Device Tree
> linked in the PCIe controller under `vpcie-supply`. If present, the
> regulator will be disabled and then enabled as part of the PCIe host
> initialization process and will be disabled when shutting down.
> 
> Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx>

Waiting for ack from Richard or Lucas.

> ---
>  .../devicetree/bindings/pci/fsl,imx6q-pcie.txt     |  4 +++
>  drivers/pci/dwc/pci-imx6.c                         | 34 +++++++++++++++++++++-
>  2 files changed, 37 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> index e3d5680875b1..cf92d3ba5a26 100644
> --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> @@ -33,6 +33,10 @@ Optional properties:
>  - reset-gpio-active-high: If present then the reset sequence using the GPIO
>    specified in the "reset-gpio" property is reversed (H=reset state,
>    L=operation state).
> +- vpcie-supply: Should specify the regulator in charge of PCIe port power.
> +  The regulator will be enabled when initializing the PCIe host and
> +  disabled either as part of the init process or when shutting down the
> +  host.
>  
>  Additional required properties for imx6sx-pcie:
>  - clock names: Must include the following additional entries:
> diff --git a/drivers/pci/dwc/pci-imx6.c b/drivers/pci/dwc/pci-imx6.c
> index 19a289b8cc94..f9b7500c9aff 100644
> --- a/drivers/pci/dwc/pci-imx6.c
> +++ b/drivers/pci/dwc/pci-imx6.c
> @@ -24,6 +24,7 @@
>  #include <linux/pci.h>
>  #include <linux/platform_device.h>
>  #include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/resource.h>
>  #include <linux/signal.h>
>  #include <linux/types.h>
> @@ -59,6 +60,7 @@ struct imx6_pcie {
>  	u32			tx_swing_full;
>  	u32			tx_swing_low;
>  	int			link_gen;
> +	struct regulator	*vpcie;
>  };
>  
>  /* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */
> @@ -310,6 +312,13 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
>  				   IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
>  		break;
>  	}
> +
> +	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> +		int ret = regulator_disable(imx6_pcie->vpcie);
> +
> +		if (ret)
> +			pr_err("failed to disable vpcie regulator: %d\n", ret);
> +	}
>  }
>  
>  static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
> @@ -376,10 +385,19 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
>  	struct device *dev = pci->dev;
>  	int ret;
>  
> +	if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
> +		ret = regulator_enable(imx6_pcie->vpcie);
> +		if (ret) {
> +			dev_err(dev, "failed to enable vpcie regulator: %d\n",
> +				ret);
> +			return;
> +		}
> +	}
> +
>  	ret = clk_prepare_enable(imx6_pcie->pcie_phy);
>  	if (ret) {
>  		dev_err(dev, "unable to enable pcie_phy clock\n");
> -		return;
> +		goto err_pcie_phy;
>  	}
>  
>  	ret = clk_prepare_enable(imx6_pcie->pcie_bus);
> @@ -439,6 +457,13 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
>  	clk_disable_unprepare(imx6_pcie->pcie_bus);
>  err_pcie_bus:
>  	clk_disable_unprepare(imx6_pcie->pcie_phy);
> +err_pcie_phy:
> +	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> +		ret = regulator_disable(imx6_pcie->vpcie);
> +		if (ret)
> +			dev_err(dev, "failed to disable vpcie regulator: %d\n",
> +				ret);
> +	}
>  }
>  
>  static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
> @@ -802,6 +827,13 @@ static int imx6_pcie_probe(struct platform_device *pdev)
>  	if (ret)
>  		imx6_pcie->link_gen = 1;
>  
> +	imx6_pcie->vpcie = devm_regulator_get_optional(&pdev->dev, "vpcie");
> +	if (IS_ERR(imx6_pcie->vpcie)) {
> +		if (PTR_ERR(imx6_pcie->vpcie) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
> +		imx6_pcie->vpcie = NULL;
> +	}
> +
>  	platform_set_drvdata(pdev, imx6_pcie);
>  
>  	ret = imx6_add_pcie_port(imx6_pcie, pdev);
> -- 
> 2.11.0
> 
> 
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