[PATCHv6 2/5] USB: gadget: atmel_usba_udc: Request an auto disabled Vbus signal IRQ instead of an auto enabled IRQ request followed by IRQ disable

From: nicolas.ferre@atmel•com (Nicolas Ferre)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCHv6 2/5] USB: gadget: atmel_usba_udc: Request an auto disabled Vbus signal IRQ instead of an auto enabled IRQ request followed by IRQ disable
Date: Fri, 23 Jan 2015 09:59:58 +0100	[thread overview]
Message-ID: <54C20D8E.4040505@atmel.com> (raw)
In-Reply-To: <0F74BBB2-B515-4A36-8C71-25F58A4D1AB6@jcrosoft.com>

Le 23/01/2015 08:43, Jean-Christophe PLAGNIOL-VILLARD a ?crit :
> 
>> On Jan 23, 2015, at 12:56 AM, Sylvain Rochet <sylvain.rochet@finsecur•com> wrote:
>>
>> 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>
>> ---
>> drivers/usb/gadget/udc/atmel_usba_udc.c | 9 ++-------
>> 1 file 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 40e5fc7..f9f305f 100644
>> --- a/drivers/usb/gadget/udc/atmel_usba_udc.c
>> +++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
>> @@ -1745,10 +1745,6 @@ 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) {
>> @@ -1769,7 +1765,6 @@ static irqreturn_t usba_vbus_irq(int irq, void *devid)
>> 		udc->vbus_prev = vbus;
>> 	}
>>
>> -out:
>> 	spin_unlock(&udc->lock);
>>
>> 	return IRQ_HANDLED;
>> @@ -2109,6 +2104,8 @@ 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);
> 
> not happy about still using the broken gpio_to_irq API
> 
> Linus can pass the IRQ via board file?
> 
> and via DT we can use IRQ directly

Absolutely not the topic of this patch series.
Maybe the subject of another patch later?

Best regards,

>> 			ret = devm_request_irq(&pdev->dev,
>> 					gpio_to_irq(udc->vbus_pin),
>> 					usba_vbus_irq, 0,
>> @@ -2118,8 +2115,6 @@ 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 */
>> -- 
>> 2.1.4
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 
> 

-- 
Nicolas Ferre