[PATCH v2 15/17] phy: qcom-qusb2: Add support for runtime PM

[Manu Gautam]

Disable clocks and dp/dm asynchronous interrupts from
PHY as part of runtime suspend.

Signed-off-by: Manu Gautam <mgautam@xxxxxxxxxxxxxx>
---
 drivers/phy/qualcomm/phy-qcom-qusb2.c | 159 ++++++++++++++++++++++++++++++++++
 1 file changed, 159 insertions(+)

diff --git a/drivers/phy/qualcomm/phy-qcom-qusb2.c b/drivers/phy/qualcomm/phy-qcom-qusb2.c
index 0e9d88b..7414272 100644
--- a/drivers/phy/qualcomm/phy-qcom-qusb2.c
+++ b/drivers/phy/qualcomm/phy-qcom-qusb2.c
@@ -56,6 +56,18 @@
 
 #define PHY_CLK_SCHEME_SEL		BIT(0)
 
+/* QUSB2PHY_INTR_CTRL register bits */
+#define DMSE_INTR_HIGH_SEL			BIT(4)
+#define DPSE_INTR_HIGH_SEL			BIT(3)
+#define CHG_DET_INTR_EN				BIT(2)
+#define DMSE_INTR_EN				BIT(1)
+#define DPSE_INTR_EN				BIT(0)
+
+/* QUSB2PHY_PLL_CORE_INPUT_OVERRIDE register bits */
+#define CORE_PLL_EN_FROM_RESET			BIT(4)
+#define CORE_RESET				BIT(5)
+#define CORE_RESET_MUX				BIT(6)
+
 #define	QUSB2PHY_PLL_ANALOG_CONTROLS_TWO	0x04
 #define	QUSB2PHY_PLL_CLOCK_INVERTERS		0x18c
 #define	QUSB2PHY_PLL_CMODE			0x2c
@@ -73,6 +85,10 @@
 #define UTMI_OTG_VBUS_VALID			BIT(20)
 #define SW_SESSVLD_SEL				BIT(28)
 
+#define QSCRATCH_CHARGING_DET_OUTPUT		0x1C
+#define LINESTATE_DP				BIT(8)
+#define LINESTATE_DM				BIT(9)
+
 struct qusb2_phy_init_tbl {
 	unsigned int offset;
 	unsigned int val;
@@ -98,6 +114,7 @@ struct qusb2_phy_init_tbl {
 
 /* set of registers with offsets different per-PHY */
 enum qusb2phy_reg_layout {
+	QUSB2PHY_PLL_CORE_INPUT_OVERRIDE,
 	QUSB2PHY_PLL_STATUS,
 	QUSB2PHY_PORT_TUNE1,
 	QUSB2PHY_PORT_TUNE2,
@@ -117,8 +134,10 @@ enum qusb2phy_reg_layout {
 	[QUSB2PHY_PORT_TUNE3]		= 0x88,
 	[QUSB2PHY_PORT_TUNE4]		= 0x8c,
 	[QUSB2PHY_PORT_TUNE5]		= 0x90,
+	[QUSB2PHY_PORT_TEST1]		= 0xb8,
 	[QUSB2PHY_PORT_TEST2]		= 0x9c,
 	[QUSB2PHY_PORT_POWERDOWN]	= 0xb4,
+	[QUSB2PHY_INTR_CTRL]		= 0xbc,
 };
 
 static const struct qusb2_phy_init_tbl msm8996_init_tbl[] = {
@@ -138,14 +157,17 @@ enum qusb2phy_reg_layout {
 };
 
 static const unsigned int qusb2_v2_regs_layout[] = {
+	[QUSB2PHY_PLL_CORE_INPUT_OVERRIDE] = 0xa8,
 	[QUSB2PHY_PLL_STATUS]		= 0x1a0,
 	[QUSB2PHY_PORT_TUNE1]		= 0x240,
 	[QUSB2PHY_PORT_TUNE2]		= 0x244,
 	[QUSB2PHY_PORT_TUNE3]		= 0x248,
 	[QUSB2PHY_PORT_TUNE4]		= 0x24c,
 	[QUSB2PHY_PORT_TUNE5]		= 0x250,
+	[QUSB2PHY_PORT_TEST1]		= 0x254,
 	[QUSB2PHY_PORT_TEST2]		= 0x258,
 	[QUSB2PHY_PORT_POWERDOWN]	= 0x210,
+	[QUSB2PHY_INTR_CTRL]		= 0x230,
 };
 
 static const struct qusb2_phy_init_tbl qusb2_v2_init_tbl[] = {
@@ -180,9 +202,13 @@ struct qusb2_phy_cfg {
 	const unsigned int *regs;
 	unsigned int mask_core_ready;
 	unsigned int disable_ctrl;
+	unsigned int autoresume_en;
 
 	/* true if PHY has PLL_TEST register to select clk_scheme */
 	bool has_pll_test;
+
+	/* true if PHY has PLL_CORE_INPUT_OVERRIDE register to reset PLL */
+	bool has_pll_override;
 };
 
 static const struct qusb2_phy_cfg msm8996_phy_cfg = {
@@ -193,6 +219,7 @@ struct qusb2_phy_cfg {
 	.has_pll_test	= true,
 	.disable_ctrl	= (CLAMP_N_EN | FREEZIO_N | POWER_DOWN),
 	.mask_core_ready = PLL_LOCKED,
+	.autoresume_en	 = BIT(3),
 };
 
 static const struct qusb2_phy_cfg qusb2_v2_phy_cfg = {
@@ -203,6 +230,8 @@ struct qusb2_phy_cfg {
 	.disable_ctrl	= (PWR_CTRL1_VREF_SUPPLY_TRIM | PWR_CTRL1_CLAMP_N_EN |
 			   POWER_DOWN),
 	.mask_core_ready = CORE_READY_STATUS,
+	.has_pll_override = true,
+	.autoresume_en	  = BIT(0),
 };
 
 static const char * const qusb2_phy_vreg_names[] = {
@@ -229,6 +258,7 @@ struct qusb2_phy_cfg {
  *
  * @cfg: phy config data
  * @has_se_clk_scheme: indicate if PHY has single-ended ref clock scheme
+ * @phy_initialized: indicate if PHY has been initialized
  * @mode: indicate current PHY mode of operation e.g. HOST or DEVICE
  */
 struct qusb2_phy {
@@ -247,6 +277,7 @@ struct qusb2_phy {
 
 	const struct qusb2_phy_cfg *cfg;
 	bool has_se_clk_scheme;
+	bool phy_initialized;
 	enum phy_mode mode;
 };
 
@@ -335,6 +366,115 @@ static int qusb2_phy_set_mode(struct phy *phy, enum phy_mode mode)
 	return 0;
 }
 
+static int __maybe_unused qusb2_phy_runtime_suspend(struct device *dev)
+{
+	struct qusb2_phy *qphy = dev_get_drvdata(dev);
+	const struct qusb2_phy_cfg *cfg = qphy->cfg;
+	u32 linestate = 0, intr_mask;
+
+	dev_vdbg(dev, "Suspending QUSB2 Phy, mode:%d\n", qphy->mode);
+
+	if (!qphy->phy_initialized) {
+		dev_vdbg(dev, "PHY not initialized, bailing out\n");
+		return 0;
+	}
+
+	/*
+	 * Enable DP/DM interrupts to detect line state changes based on current
+	 * state. In other words, enable the triggers _opposite_ of what the
+	 * current D+/D- levels are e.g. if currently D+ high, D- low
+	 * (HS 'J'/Suspend), configure the mask to trigger on D+ low OR D- high
+	 */
+	if (qphy->qscratch_base) {
+		linestate = readl(qphy->qscratch_base +
+				  QSCRATCH_CHARGING_DET_OUTPUT);
+		intr_mask = DPSE_INTR_EN | DMSE_INTR_EN;
+		if (!(linestate & LINESTATE_DP)) /* D+ low */
+			intr_mask |= DPSE_INTR_HIGH_SEL;
+		if (!(linestate & LINESTATE_DM)) /* D- low */
+			intr_mask |= DMSE_INTR_HIGH_SEL;
+
+		writel(intr_mask, qphy->base + cfg->regs[QUSB2PHY_INTR_CTRL]);
+	}
+
+	/* hold core PLL into reset */
+	if (cfg->has_pll_override) {
+		qusb2_setbits(qphy->base,
+			      cfg->regs[QUSB2PHY_PLL_CORE_INPUT_OVERRIDE],
+			      CORE_PLL_EN_FROM_RESET | CORE_RESET |
+			      CORE_RESET_MUX);
+	}
+
+	/* enable phy auto-resume */
+	if (linestate & (LINESTATE_DP | LINESTATE_DM)) {
+		qusb2_setbits(qphy->base, cfg->regs[QUSB2PHY_PORT_TEST1],
+			      cfg->autoresume_en);
+		/* Autoresume bit has to be toggled in order to enable it */
+		qusb2_clrbits(qphy->base, cfg->regs[QUSB2PHY_PORT_TEST1],
+			      cfg->autoresume_en);
+	}
+
+	if (!qphy->has_se_clk_scheme)
+		clk_disable_unprepare(qphy->ref_clk);
+
+	clk_disable_unprepare(qphy->cfg_ahb_clk);
+	clk_disable_unprepare(qphy->iface_clk);
+
+	return 0;
+}
+
+static int __maybe_unused qusb2_phy_runtime_resume(struct device *dev)
+{
+	struct qusb2_phy *qphy = dev_get_drvdata(dev);
+	const struct qusb2_phy_cfg *cfg = qphy->cfg;
+	int ret;
+
+	dev_vdbg(dev, "Resuming QUSB2 phy, mode:%d\n", qphy->mode);
+
+	if (!qphy->phy_initialized) {
+		dev_vdbg(dev, "PHY not initialized, bailing out\n");
+		return 0;
+	}
+
+	ret = clk_prepare_enable(qphy->iface_clk);
+	if (ret) {
+		dev_err(dev, "failed to enable iface_clk, %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(qphy->cfg_ahb_clk);
+	if (ret) {
+		dev_err(dev, "failed to enable cfg ahb clock, %d\n", ret);
+		goto disable_iface_clk;
+	}
+
+	if (!qphy->has_se_clk_scheme) {
+		clk_prepare_enable(qphy->ref_clk);
+		if (ret) {
+			dev_err(dev, "failed to enable ref clk, %d\n", ret);
+			goto disable_ahb_clk;
+		}
+	}
+
+	writel(0x0, qphy->base + cfg->regs[QUSB2PHY_INTR_CTRL]);
+
+	/* bring core PLL out of reset */
+	if (cfg->has_pll_override) {
+		qusb2_clrbits(qphy->base,
+			      cfg->regs[QUSB2PHY_PLL_CORE_INPUT_OVERRIDE],
+			      CORE_RESET | CORE_RESET_MUX);
+	}
+
+	return 0;
+
+disable_ahb_clk:
+	clk_disable_unprepare(qphy->cfg_ahb_clk);
+disable_iface_clk:
+	clk_disable_unprepare(qphy->iface_clk);
+
+	return ret;
+}
+
 static int qusb2_phy_init(struct phy *phy)
 {
 	struct qusb2_phy *qphy = phy_get_drvdata(phy);
@@ -459,6 +599,7 @@ static int qusb2_phy_init(struct phy *phy)
 		ret = -EBUSY;
 		goto disable_ref_clk;
 	}
+	qphy->phy_initialized = true;
 
 	return 0;
 
@@ -495,6 +636,8 @@ static int qusb2_phy_exit(struct phy *phy)
 
 	regulator_bulk_disable(ARRAY_SIZE(qphy->vregs), qphy->vregs);
 
+	qphy->phy_initialized = false;
+
 	return 0;
 }
 
@@ -517,6 +660,11 @@ static int qusb2_phy_exit(struct phy *phy)
 };
 MODULE_DEVICE_TABLE(of, qusb2_phy_of_match_table);
 
+static const struct dev_pm_ops qusb2_phy_pm_ops = {
+	SET_RUNTIME_PM_OPS(qusb2_phy_runtime_suspend,
+			   qusb2_phy_runtime_resume, NULL)
+};
+
 static int qusb2_phy_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -604,11 +752,19 @@ static int qusb2_phy_probe(struct platform_device *pdev)
 		qphy->cell = NULL;
 		dev_dbg(dev, "failed to lookup tune2 hstx trim value\n");
 	}
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	/*
+	 * Prevent runtime pm from being ON by default. Users can enable
+	 * it using power/control in sysfs.
+	 */
+	pm_runtime_forbid(dev);
 
 	generic_phy = devm_phy_create(dev, NULL, &qusb2_phy_gen_ops);
 	if (IS_ERR(generic_phy)) {
 		ret = PTR_ERR(generic_phy);
 		dev_err(dev, "failed to create phy, %d\n", ret);
+		pm_runtime_disable(dev);
 		return ret;
 	}
 	qphy->phy = generic_phy;
@@ -619,6 +775,8 @@ static int qusb2_phy_probe(struct platform_device *pdev)
 	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 	if (!IS_ERR(phy_provider))
 		dev_info(dev, "Registered Qcom-QUSB2 phy\n");
+	else
+		pm_runtime_disable(dev);
 
 	return PTR_ERR_OR_ZERO(phy_provider);
 }
@@ -627,6 +785,7 @@ static int qusb2_phy_probe(struct platform_device *pdev)
 	.probe		= qusb2_phy_probe,
 	.driver = {
 		.name	= "qcom-qusb2-phy",
+		.pm	= &qusb2_phy_pm_ops,
 		.of_match_table = qusb2_phy_of_match_table,
 	},
 };
-- 
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