On 10/05/16 12:58, Felipe Balbi wrote:
>
> Hi,
>
> Roger Quadros <rogerq@xxxxxx> writes:
>> We intend to share this interrupt with the OTG driver an to ensure
>> that irqflags match for the shared interrupt handlers we use
>> request_threaded_irq()
>>
>> If we don't use request_treaded_irq() then forced threaded irq will
>> set IRQF_ONESHOT and this won't match with the OTG IRQ handler's
>> IRQ flags.
>>
>> NOTE: OTG IRQ handler is yet to be added. This is a preparatory step.
>>
>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>> ---
>> drivers/usb/dwc3/dwc3-omap.c | 12 +++++++++---
>> 1 file changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/dwc3-omap.c b/drivers/usb/dwc3/dwc3-omap.c
>> index 59ea35f..6504e94 100644
>> --- a/drivers/usb/dwc3/dwc3-omap.c
>> +++ b/drivers/usb/dwc3/dwc3-omap.c
>> @@ -272,16 +272,22 @@ static irqreturn_t dwc3_omap_interrupt(int irq, void *_omap)
>> {
>> struct dwc3_omap *omap = _omap;
>> u32 reg;
>> + int ret = IRQ_NONE;
>>
>> reg = dwc3_omap_read_irqmisc_status(omap);
>>
>> + if (reg)
>> + ret = IRQ_HANDLED;
>> +
>> dwc3_omap_write_irqmisc_status(omap, reg);
>>
>> reg = dwc3_omap_read_irq0_status(omap);
>> + if (reg)
>> + ret = IRQ_HANDLED;
>>
>> dwc3_omap_write_irq0_status(omap, reg);
>>
>> - return IRQ_HANDLED;
>> + return ret;
>> }
>>
>> static void dwc3_omap_enable_irqs(struct dwc3_omap *omap)
>> @@ -497,8 +503,8 @@ static int dwc3_omap_probe(struct platform_device *pdev)
>> /* check the DMA Status */
>> reg = dwc3_omap_readl(omap->base, USBOTGSS_SYSCONFIG);
>>
>> - ret = devm_request_irq(dev, omap->irq, dwc3_omap_interrupt, 0,
>> - "dwc3-omap", omap);
>> + ret = devm_request_threaded_irq(dev, omap->irq, dwc3_omap_interrupt,
>> + NULL, 0, "dwc3-omap", omap);
>
> if you're using threaded_irq, it's better to have a NULL top half and
> valid bottom half.
But in this case we don't need a bottom half as there is nothing to do :).
>
> In fact, since this will be shared, you could do a proper preparation
> and on top half check if $this device generated the IRQ and
> conditionally schedule the bottom half. Don't forget to mask device's
> interrupts from top half so you can run without IRQF_ONESHOT.
>
Why do this at all if there is nothing to do in the bottom half?
cheers,
-roger
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