usb: gadget: atmel_usba_udc: Request an auto disabled Vbus signal IRQ

Vbus IRQ handler needs a started UDC driver to work because it uses
udc->driver, which is set by the UDC start handler. The previous way
chosen was to return from interrupt if udc->driver is NULL using a
spinlock around the check.

We now request an auto disabled (IRQ_NOAUTOEN) Vbus signal IRQ instead
of an auto enabled IRQ followed by disable_irq(). This way we remove the
very small timeslot of enabled IRQ which existed previously between
request() and disable(). We don't need anymore to check if udc->driver
is NULL in IRQ handler.

Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 2 insertions, 7 deletions

diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
index e63c6fc8173b..bbbd5f11f767 100644
--- a/drivers/usb/gadget/udc/atmel_usba_udc.c
+++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
@@ -1749,10 +1749,6 @@ static irqreturn_t usba_vbus_irq(int irq, void *devid)
 
         spin_lock(&udc->lock);
 
-        /* May happen if Vbus pin toggles during probe() */
-        if (!udc->driver)
-                goto out;
-
         vbus = vbus_is_present(udc);
         if (vbus != udc->vbus_prev) {
                 if (vbus) {
@@ -1773,7 +1769,6 @@ static irqreturn_t usba_vbus_irq(int irq, void *devid)
                 udc->vbus_prev = vbus;
         }
 
-out:
         spin_unlock(&udc->lock);
 
         return IRQ_HANDLED;
@@ -2113,6 +2108,8 @@ static int usba_udc_probe(struct platform_device *pdev)
 
         if (gpio_is_valid(udc->vbus_pin)) {
                 if (!devm_gpio_request(&pdev->dev, udc->vbus_pin, "atmel_usba_udc")) {
+                        irq_set_status_flags(gpio_to_irq(udc->vbus_pin),
+                                        IRQ_NOAUTOEN);
                         ret = devm_request_irq(&pdev->dev,
                                         gpio_to_irq(udc->vbus_pin),
                                         usba_vbus_irq, 0,
@@ -2122,8 +2119,6 @@ static int usba_udc_probe(struct platform_device *pdev)
                                 dev_warn(&udc->pdev->dev,
                                          "failed to request vbus irq; "
                                          "assuming always on\n");
-                        } else {
-                                disable_irq(gpio_to_irq(udc->vbus_pin));
                         }
                 } else {
                         /* gpio_request fail so use -EINVAL for gpio_is_valid */