phy: usb: Add "wake on" functionality

Add the ability to handle USB wake events from USB devices when
in S2 mode. Typically there is some additional configuration
needed to tell the USB device to generate the wake event when
suspended but this varies with the different USB device classes.
For example, on USB Ethernet dongles, ethtool should be used to
enable the magic packet wake functionality in the dongle.
NOTE:  This requires that the "power/wakeup" sysfs entry for
the USB device generating the wakeup be set to "enabled".

This functionality requires a special hardware sideband path that
will trigger the AON_PM_L2 interrupt needed to wake the system from
S2 even though the USB host controllers are in IDDQ (low power state)
and most USB related clocks are shut off. For the sideband signaling
to work we need to leave the usbx_freerun clock running, but this
clock consumes very little power by design. There's a bug in the
XHCI wake hardware so only EHCI/OHCI wake is currently supported.

Signed-off-by: Al Cooper <alcooperx@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

1 files changed, 45 insertions, 3 deletions

diff --git a/drivers/phy/broadcom/phy-brcm-usb.c b/drivers/phy/broadcom/phy-brcm-usb.c
index 634afc803778..cca04d60f2d2 100644
--- a/drivers/phy/broadcom/phy-brcm-usb.c
+++ b/drivers/phy/broadcom/phy-brcm-usb.c
@@ -57,11 +57,22 @@ struct brcm_usb_phy_data {
 	bool			has_xhci;
 	struct clk		*usb_20_clk;
 	struct clk		*usb_30_clk;
+	struct clk		*suspend_clk;
 	struct mutex		mutex;	/* serialize phy init */
 	int			init_count;
+	int			wake_irq;
 	struct brcm_usb_phy	phys[BRCM_USB_PHY_ID_MAX];
 };
 
+static irqreturn_t brcm_usb_phy_wake_isr(int irq, void *dev_id)
+{
+	struct phy *gphy = dev_id;
+
+	pm_wakeup_event(&gphy->dev, 0);
+
+	return IRQ_HANDLED;
+}
+
 static int brcm_usb_phy_init(struct phy *gphy)
 {
 	struct brcm_usb_phy *phy = phy_get_drvdata(gphy);
@@ -76,6 +87,7 @@ static int brcm_usb_phy_init(struct phy *gphy)
 	if (priv->init_count++ == 0) {
 		clk_prepare_enable(priv->usb_20_clk);
 		clk_prepare_enable(priv->usb_30_clk);
+		clk_prepare_enable(priv->suspend_clk);
 		brcm_usb_init_common(&priv->ini);
 	}
 	mutex_unlock(&priv->mutex);
@@ -108,6 +120,7 @@ static int brcm_usb_phy_exit(struct phy *gphy)
 		brcm_usb_uninit_common(&priv->ini);
 		clk_disable_unprepare(priv->usb_20_clk);
 		clk_disable_unprepare(priv->usb_30_clk);
+		clk_disable_unprepare(priv->suspend_clk);
 	}
 	mutex_unlock(&priv->mutex);
 	phy->inited = false;
@@ -228,11 +241,12 @@ static const struct attribute_group brcm_usb_phy_group = {
 	.attrs = brcm_usb_phy_attrs,
 };
 
-static int brcm_usb_phy_dvr_init(struct device *dev,
+static int brcm_usb_phy_dvr_init(struct platform_device *pdev,
 				 struct brcm_usb_phy_data *priv,
 				 struct device_node *dn)
 {
-	struct phy *gphy;
+	struct device *dev = &pdev->dev;
+	struct phy *gphy = NULL;
 	int err;
 
 	priv->usb_20_clk = of_clk_get_by_name(dn, "sw_usb");
@@ -275,6 +289,28 @@ static int brcm_usb_phy_dvr_init(struct device *dev,
 		if (err)
 			return err;
 	}
+
+	priv->suspend_clk = clk_get(dev, "usb0_freerun");
+	if (IS_ERR(priv->suspend_clk)) {
+		dev_err(dev, "Suspend Clock not found in Device Tree\n");
+		priv->suspend_clk = NULL;
+	}
+
+	priv->wake_irq = platform_get_irq_byname(pdev, "wake");
+	if (priv->wake_irq < 0)
+		priv->wake_irq = platform_get_irq_byname(pdev, "wakeup");
+	if (priv->wake_irq >= 0) {
+		err = devm_request_irq(dev, priv->wake_irq,
+				       brcm_usb_phy_wake_isr, 0,
+				       dev_name(dev), gphy);
+		if (err < 0)
+			return err;
+		device_set_wakeup_capable(dev, 1);
+	} else {
+		dev_info(dev,
+			 "Wake interrupt missing, system wake not supported\n");
+	}
+
 	return 0;
 }
 
@@ -335,7 +371,7 @@ static int brcm_usb_phy_probe(struct platform_device *pdev)
 	if (of_property_read_bool(dn, "brcm,has-eohci"))
 		priv->has_eohci = true;
 
-	err = brcm_usb_phy_dvr_init(dev, priv, dn);
+	err = brcm_usb_phy_dvr_init(pdev, priv, dn);
 	if (err)
 		return err;
 
@@ -386,10 +422,13 @@ static int brcm_usb_phy_suspend(struct device *dev)
 		if (priv->phys[BRCM_USB_PHY_2_0].inited)
 			brcm_usb_uninit_eohci(&priv->ini);
 		brcm_usb_uninit_common(&priv->ini);
+		brcm_usb_wake_enable(&priv->ini, true);
 		if (priv->phys[BRCM_USB_PHY_3_0].inited)
 			clk_disable_unprepare(priv->usb_30_clk);
 		if (priv->phys[BRCM_USB_PHY_2_0].inited)
 			clk_disable_unprepare(priv->usb_20_clk);
+		if (priv->wake_irq >= 0)
+			enable_irq_wake(priv->wake_irq);
 	}
 	return 0;
 }
@@ -400,6 +439,7 @@ static int brcm_usb_phy_resume(struct device *dev)
 
 	clk_prepare_enable(priv->usb_20_clk);
 	clk_prepare_enable(priv->usb_30_clk);
+	brcm_usb_wake_enable(&priv->ini, false);
 	brcm_usb_init_ipp(&priv->ini);
 
 	/*
@@ -407,6 +447,8 @@ static int brcm_usb_phy_resume(struct device *dev)
 	 * Uninitialize anything that wasn't previously initialized.
 	 */
 	if (priv->init_count) {
+		if (priv->wake_irq >= 0)
+			disable_irq_wake(priv->wake_irq);
 		brcm_usb_init_common(&priv->ini);
 		if (priv->phys[BRCM_USB_PHY_2_0].inited) {
 			brcm_usb_init_eohci(&priv->ini);