linux-kernel - [PATCH v9 6/8] PCI: imx6: Disable clocks and regulators after link is down

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Message-Id: <1651801629-30223-7-git-send-email-hongxing.zhu@nxp.com>
Date:   Fri,  6 May 2022 09:47:07 +0800
From:   Richard Zhu <hongxing.zhu@....com>
To:     l.stach@...gutronix.de, bhelgaas@...gle.com, robh+dt@...nel.org,
        broonie@...nel.org, lorenzo.pieralisi@....com,
        jingoohan1@...il.com, festevam@...il.com,
        francesco.dolcini@...adex.com
Cc:     hongxing.zhu@....com, linux-pci@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kernel@...gutronix.de, linux-imx@....com
Subject: [PATCH v9 6/8] PCI: imx6: Disable clocks and regulators after link is down

Since i.MX PCIe doesn't support hot-plug, reduce power consumption
as much as possible by disabling clocks and regulators and returning
error when the link is down.

Signed-off-by: Richard Zhu <hongxing.zhu@....com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 3ce3993d5797..d122c12193a6 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -845,7 +845,9 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 	/* Start LTSSM. */
 	imx6_pcie_ltssm_enable(dev);
 
-	dw_pcie_wait_for_link(pci);
+	ret = dw_pcie_wait_for_link(pci);
+	if (ret)
+		goto err_out;
 
 	if (pci->link_gen == 2) {
 		/* Allow Gen2 mode after the link is up. */
@@ -876,12 +878,14 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 			ret = imx6_pcie_wait_for_speed_change(imx6_pcie);
 			if (ret) {
 				dev_err(dev, "Failed to bring link up!\n");
-				goto err_reset_phy;
+				goto err_out;
 			}
 		}
 
 		/* Make sure link training is finished as well! */
-		dw_pcie_wait_for_link(pci);
+		ret = dw_pcie_wait_for_link(pci);
+		if (ret)
+			goto err_out;
 	} else {
 		dev_info(dev, "Link: Gen2 disabled\n");
 	}
@@ -890,11 +894,18 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 	dev_info(dev, "Link up, Gen%i\n", tmp & PCI_EXP_LNKSTA_CLS);
 	return 0;
 
-err_reset_phy:
+err_out:
 	dev_dbg(dev, "PHY DEBUG_R0=0x%08x DEBUG_R1=0x%08x\n",
 		dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG0),
 		dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG1));
 	imx6_pcie_reset_phy(imx6_pcie);
+	imx6_pcie_clk_disable(imx6_pcie);
+	if (imx6_pcie->phy != NULL) {
+		phy_power_off(imx6_pcie->phy);
+		phy_exit(imx6_pcie->phy);
+	}
+	if (imx6_pcie->vpcie)
+		regulator_disable(imx6_pcie->vpcie);
 	return ret;
 }
 
-- 
2.25.1