linux-kernel - [PATCH v6 4/5] phy: qcom: Add power down/up callbacks to pcie phy

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Date:   Fri,  9 Sep 2022 14:14:43 +0530
From:   Krishna chaitanya chundru <quic_krichai@...cinc.com>
To:     helgaas@...nel.org
Cc:     linux-pci@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, mka@...omium.org,
        quic_vbadigan@...cinc.com, quic_hemantk@...cinc.com,
        quic_nitegupt@...cinc.com, quic_skananth@...cinc.com,
        quic_ramkri@...cinc.com, manivannan.sadhasivam@...aro.org,
        swboyd@...omium.org, dmitry.baryshkov@...aro.org,
        Krishna chaitanya chundru <quic_krichai@...cinc.com>,
        Stanimir Varbanov <svarbanov@...sol.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>,
        linux-phy@...ts.infradead.org (open list:GENERIC PHY FRAMEWORK)
Subject: [PATCH v6 4/5] phy: qcom: Add power down/up callbacks to pcie phy

Add phy power down/up callbacks to pcie phy. Using these callbacks
we can release phy resources like phy specific clocks but continue
maintain pcie link in l1ss state.

This can help in parking pcie link in l1ss state during system
suspend (S3).

Signed-off-by: Krishna chaitanya chundru <quic_krichai@...cinc.com>
---
 drivers/pci/controller/dwc/pcie-qcom.c   |  6 ++--
 drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 50 ++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 15c2067..1d4b1b0 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1326,7 +1326,8 @@ static int qcom_pcie_resume_2_7_0(struct qcom_pcie *pcie)
 
 	ret = clk_bulk_prepare_enable(res->num_clks, res->clks);
 
-	phy_power_on(pcie->phy);
+	/* Bring back PHY from power down */
+	phy_power_up(pcie->phy);
 
 	return ret;
 }
@@ -1335,7 +1336,8 @@ static int qcom_pcie_suspend_2_7_0(struct qcom_pcie *pcie)
 {
 	struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0;
 
-	phy_power_off(pcie->phy);
+	/* Power down PHY to park the link state in L1ss */
+	phy_power_down(pcie->phy);
 
 	clk_bulk_disable_unprepare(res->num_clks, res->clks);
 	return 0;
diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
index 3ddbb8e..c6b3b82 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
@@ -2145,6 +2145,54 @@ static int qcom_qmp_phy_pcie_exit(struct phy *phy)
 	return 0;
 }
 
+static int qcom_qmp_phy_pcie_power_up(struct phy *phy)
+{
+	struct qmp_phy *qphy = phy_get_drvdata(phy);
+	struct qcom_qmp *qmp = qphy->qmp;
+	const struct qmp_phy_cfg *cfg = qphy->cfg;
+	int ret;
+
+	ret = clk_bulk_prepare_enable(cfg->num_clks, qmp->clks);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(qphy->pipe_clk);
+	if (ret)
+		return ret;
+
+	/* Pull out PHY from POWER DOWN state */
+	if (cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL]) {
+		qphy_setbits(qphy->pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL],
+			     cfg->pwrdn_ctrl);
+	} else {
+		qphy_setbits(qphy->pcs, QPHY_V2_PCS_POWER_DOWN_CONTROL,
+				cfg->pwrdn_ctrl);
+	}
+
+	return 0;
+}
+
+static int qcom_qmp_phy_pcie_power_down(struct phy *phy)
+{
+	struct qmp_phy *qphy = phy_get_drvdata(phy);
+	struct qcom_qmp *qmp = qphy->qmp;
+	const struct qmp_phy_cfg *cfg = qphy->cfg;
+
+	clk_disable_unprepare(qphy->pipe_clk);
+	clk_bulk_disable_unprepare(cfg->num_clks, qmp->clks);
+
+	/* Put PHY into POWER DOWN state: active low */
+	if (cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL]) {
+		qphy_clrbits(qphy->pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL],
+			     cfg->pwrdn_ctrl);
+	} else {
+		qphy_clrbits(qphy->pcs, QPHY_V2_PCS_POWER_DOWN_CONTROL,
+				cfg->pwrdn_ctrl);
+	}
+
+	return 0;
+}
+
 static int qcom_qmp_phy_pcie_enable(struct phy *phy)
 {
 	int ret;
@@ -2304,6 +2352,8 @@ static const struct phy_ops qcom_qmp_phy_pcie_ops = {
 	.power_on	= qcom_qmp_phy_pcie_enable,
 	.power_off	= qcom_qmp_phy_pcie_disable,
 	.set_mode	= qcom_qmp_phy_pcie_set_mode,
+	.power_down	= qcom_qmp_phy_pcie_power_down,
+	.power_up	= qcom_qmp_phy_pcie_power_up,
 	.owner		= THIS_MODULE,
 };
 
-- 
2.7.4