[PATCH 1/2] usb: bcma: control VBUS via a regulator instead of a GPIO

[Rosen Penev]

bcma-hcd drives the USB power line by grabbing the undocumented
"vcc-gpio" from the controller node and poking it through gpiolib.
Besides relying on a non-standard binding, this cannot work on boards
such as the NETGEAR R7000 and R8000 where one chipcommon GPIO powers
both the USB2 and USB3 cores: the two controllers each request that
GPIO exclusively, so the second one fails with -EBUSY and its port
stays dead.

Use the standard regulator interface instead. Each core obtains its
(shared) VBUS supply through devm_regulator_get_optional() and the
regulator core reference-counts the enable/disable requests, allowing
both controllers to drive one GPIO without conflicts.

Assisted-by: LLM
Signed-off-by: Rosen Penev <rosenp at gmail.com>
---
 drivers/usb/host/bcma-hcd.c | 45 +++++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 14 deletions(-)

diff --git a/drivers/usb/host/bcma-hcd.c b/drivers/usb/host/bcma-hcd.c
index 519386255886..394ba9e5a7f7 100644
--- a/drivers/usb/host/bcma-hcd.c
+++ b/drivers/usb/host/bcma-hcd.c
@@ -20,12 +20,12 @@
  */
 #include <linux/bcma/bcma.h>
 #include <linux/delay.h>
-#include <linux/gpio/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
+#include <linux/regulator/consumer.h>
 #include <linux/usb/ehci_pdriver.h>
 #include <linux/usb/ohci_pdriver.h>
 
@@ -40,7 +40,7 @@ struct bcma_hcd_device {
 	struct bcma_device *core;
 	struct platform_device *ehci_dev;
 	struct platform_device *ohci_dev;
-	struct gpio_desc *gpio_desc;
+	struct regulator *regulator;
 };
 
 /* Wait for bitmask in a register to get set or cleared.
@@ -280,14 +280,20 @@ static int bcma_hcd_usb20_ns_init(struct bcma_hcd_device *bcma_hcd)
 	return 0;
 }
 
-static void bcma_hci_platform_power_gpio(struct bcma_device *dev, bool val)
+static int bcma_hci_platform_power(struct bcma_device *dev, bool on)
 {
 	struct bcma_hcd_device *usb_dev = bcma_get_drvdata(dev);
+	int err;
+
+	if (!usb_dev->regulator)
+		return 0;
 
-	if (!usb_dev->gpio_desc)
-		return;
+	if (on)
+		err = regulator_enable(usb_dev->regulator);
+	else
+		err = regulator_disable(usb_dev->regulator);
 
-	gpiod_set_value(usb_dev->gpio_desc, val);
+	return err;
 }
 
 static const struct usb_ehci_pdata ehci_pdata = {
@@ -405,11 +411,14 @@ static int bcma_hcd_probe(struct bcma_device *core)
 		return -ENOMEM;
 	usb_dev->core = core;
 
-	usb_dev->gpio_desc = devm_gpiod_get_optional(&core->dev, "vcc",
-						     GPIOD_OUT_HIGH);
-	if (IS_ERR(usb_dev->gpio_desc))
-		return dev_err_probe(&core->dev, PTR_ERR(usb_dev->gpio_desc),
-				     "error obtaining VCC GPIO");
+	usb_dev->regulator = devm_regulator_get_optional(&core->dev, "vbus");
+	if (IS_ERR(usb_dev->regulator)) {
+		return PTR_ERR(usb_dev->regulator);
+
+	err = regulator_enable(usb_dev->regulator);
+	if (err)
+		return dev_err_probe(&core->dev, err,
+				     "error enabling VCC regulator");
 
 	switch (core->id.id) {
 	case BCMA_CORE_USB20_HOST:
@@ -452,7 +461,7 @@ static void bcma_hcd_remove(struct bcma_device *dev)
 
 static void bcma_hcd_shutdown(struct bcma_device *dev)
 {
-	bcma_hci_platform_power_gpio(dev, false);
+	bcma_hci_platform_power(dev, false);
 	bcma_core_disable(dev, 0);
 }
 
@@ -460,7 +469,11 @@ static void bcma_hcd_shutdown(struct bcma_device *dev)
 
 static int bcma_hcd_suspend(struct bcma_device *dev)
 {
-	bcma_hci_platform_power_gpio(dev, false);
+	int err;
+
+	err = bcma_hci_platform_power(dev, false);
+	if (err)
+		return err;
 	bcma_core_disable(dev, 0);
 
 	return 0;
@@ -468,7 +481,11 @@ static int bcma_hcd_suspend(struct bcma_device *dev)
 
 static int bcma_hcd_resume(struct bcma_device *dev)
 {
-	bcma_hci_platform_power_gpio(dev, true);
+	int err;
+
+	err = bcma_hci_platform_power(dev, true);
+	if (err)
+		return err;
 	bcma_core_enable(dev, 0);
 
 	return 0;
-- 
2.55.0