linux-kernel - [PATCH] usb: host: ehci-platform: add support for optional external vbus supply

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Date:   Tue, 20 Feb 2018 10:11:45 +0100
From:   Amelie Delaunay <amelie.delaunay@...com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Tony Prisk <linux@...sktech.co.nz>,
        Alan Stern <stern@...land.harvard.edu>
CC:     <linux-usb@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Amelie Delaunay <amelie.delaunay@...com>
Subject: [PATCH] usb: host: ehci-platform: add support for optional external vbus supply

On some boards, especially when vbus supply requires large current,
and the charge pump on the PHY isn't enough, an external vbus power switch
may be used.
Add support for this optional external vbus supply in ehci-platform.

Signed-off-by: Amelie Delaunay <amelie.delaunay@...com>
---
 Documentation/devicetree/bindings/usb/usb-ehci.txt |  1 +
 drivers/usb/host/ehci-platform.c                   | 23 ++++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/usb-ehci.txt b/Documentation/devicetree/bindings/usb/usb-ehci.txt
index 3efde12..fc480cd 100644
--- a/Documentation/devicetree/bindings/usb/usb-ehci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-ehci.txt
@@ -19,6 +19,7 @@ Optional properties:
  - phys : phandle + phy specifier pair
  - phy-names : "usb"
  - resets : phandle + reset specifier pair
+ - vbus-supply : phandle of regulator supplying vbus
 
 Example (Sequoia 440EPx):
     ehci@...00300 {
diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
index b065a96..76cc781 100644
--- a/drivers/usb/host/ehci-platform.c
+++ b/drivers/usb/host/ehci-platform.c
@@ -29,6 +29,7 @@
 #include <linux/of.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
 #include <linux/reset.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
@@ -46,6 +47,7 @@ struct ehci_platform_priv {
 	struct reset_control *rsts;
 	struct phy **phys;
 	int num_phys;
+	struct regulator *vbus_supply;
 	bool reset_on_resume;
 };
 
@@ -99,6 +101,15 @@ static int ehci_platform_power_on(struct platform_device *dev)
 		}
 	}
 
+	if (priv->vbus_supply) {
+		ret = regulator_enable(priv->vbus_supply);
+		if (ret) {
+			dev_err(&dev->dev,
+				"failed to enable vbus supply: %d\n", ret);
+			goto err_exit_phy;
+		}
+	}
+
 	return 0;
 
 err_exit_phy:
@@ -119,6 +130,9 @@ static void ehci_platform_power_off(struct platform_device *dev)
 	struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
 	int clk, phy_num;
 
+	if (priv->vbus_supply)
+		regulator_disable(priv->vbus_supply);
+
 	for (phy_num = 0; phy_num < priv->num_phys; phy_num++) {
 		phy_power_off(priv->phys[phy_num]);
 		phy_exit(priv->phys[phy_num]);
@@ -247,6 +261,15 @@ static int ehci_platform_probe(struct platform_device *dev)
 	if (err)
 		goto err_put_clks;
 
+	priv->vbus_supply = devm_regulator_get_optional(&dev->dev, "vbus");
+	if (IS_ERR(priv->vbus_supply)) {
+		err = PTR_ERR(priv->vbus_supply);
+		if (err == -ENODEV)
+			priv->vbus_supply = NULL;
+		else
+			goto err_reset;
+	}
+
 	if (pdata->big_endian_desc)
 		ehci->big_endian_desc = 1;
 	if (pdata->big_endian_mmio)
-- 
2.7.4