[PATCH V4 2/8] PCI: imx6: Add skip_pwrctrl_off flag support

["Sherry Sun (OSS)" <sherry.sun@oss.nxp.com>]

From: Sherry Sun <sherry.sun@nxp.com>

Use dw_pcie_rp::skip_pwrctrl_off to avoid powering off devices during
suspend to preserve wakeup capability of the devices and also not to power
on the devices in the init path.

This allows controller power-off to be skipped when some devices(e.g. M.2
cards key E without auxiliary power) required to support PCIe L2 link state
and wake-up mechanisms.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 1b535bb6fd31..0685573fee71 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -1382,10 +1382,12 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
 		}
 	}
 
-	ret = pci_pwrctrl_power_on_devices(dev);
-	if (ret) {
-		dev_err(dev, "failed to power on pwrctrl devices\n");
-		goto err_reg_disable;
+	if (!pp->skip_pwrctrl_off) {
+		ret = pci_pwrctrl_power_on_devices(dev);
+		if (ret) {
+			dev_err(dev, "failed to power on pwrctrl devices\n");
+			goto err_reg_disable;
+		}
 	}
 
 	ret = imx_pcie_clk_enable(imx_pcie);
@@ -1454,7 +1456,8 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
 err_clk_disable:
 	imx_pcie_clk_disable(imx_pcie);
 err_pwrctrl_power_off:
-	pci_pwrctrl_power_off_devices(dev);
+	if (!pp->skip_pwrctrl_off)
+		pci_pwrctrl_power_off_devices(dev);
 err_reg_disable:
 	if (imx_pcie->vpcie)
 		regulator_disable(imx_pcie->vpcie);
@@ -1473,7 +1476,8 @@ static void imx_pcie_host_exit(struct dw_pcie_rp *pp)
 	}
 	imx_pcie_clk_disable(imx_pcie);
 
-	pci_pwrctrl_power_off_devices(pci->dev);
+	if (!pci->pp.skip_pwrctrl_off)
+		pci_pwrctrl_power_off_devices(pci->dev);
 	if (imx_pcie->vpcie)
 		regulator_disable(imx_pcie->vpcie);
 }
@@ -1990,11 +1994,14 @@ static int imx_pcie_probe(struct platform_device *pdev)
 static void imx_pcie_shutdown(struct platform_device *pdev)
 {
 	struct imx_pcie *imx_pcie = platform_get_drvdata(pdev);
+	struct dw_pcie *pci = imx_pcie->pci;
+	struct dw_pcie_rp *pp = &pci->pp;
 
 	/* bring down link, so bootloader gets clean state in case of reboot */
 	imx_pcie_assert_core_reset(imx_pcie);
 	imx_pcie_assert_perst(imx_pcie, true);
-	pci_pwrctrl_power_off_devices(&pdev->dev);
+	if (!pp->skip_pwrctrl_off)
+		pci_pwrctrl_power_off_devices(&pdev->dev);
 	pci_pwrctrl_destroy_devices(&pdev->dev);
 }
 
-- 
2.50.1