From: Daniel Mack <daniel@zonque.org>
To: devicetree@vger.kernel.org, linux-serial@vger.kernel.org
Cc: gregkh@linuxfoundation.org, robh+dt@kernel.org, jslaby@suse.com,
jringle@gridpoint.com, m.brock@vanmierlo.com,
pascal.huerst@gmail.com, Daniel Mack <daniel@zonque.org>
Subject: [PATCH v3 5/6] sc16is7xx: Allow sharing the IRQ line
Date: Thu, 21 May 2020 11:11:51 +0200 [thread overview]
Message-ID: <20200521091152.404404-6-daniel@zonque.org> (raw)
In-Reply-To: <20200521091152.404404-1-daniel@zonque.org>
When the interrupt line is shared with other devices, the IRQ must be
level-triggered, as only one device can trigger a falling edge. To support
this, try to acquire the IRQ with IRQF_TRIGGER_LOW|IRQF_SHARED first.
Interrupt controllers that lack support for level-triggers will return an
error, in which case the driver will now retry the acqusition with
IRQF_TRIGGER_FALLING, which was also the default before.
Signed-off-by: Daniel Mack <daniel@zonque.org>
---
drivers/tty/serial/sc16is7xx.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index cebc0cf9c30e..7e2360f8e393 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1313,7 +1313,19 @@ static int sc16is7xx_probe(struct device *dev,
s->p[u].irda_mode = true;
}
- /* Setup interrupt */
+ /*
+ * Setup interrupt. We first try to acquire the IRQ line as level IRQ.
+ * If that succeeds, we can allow sharing the interrupt as well.
+ * In case the interrupt controller doesn't support that, we fall
+ * back to a non-shared falling-edge trigger.
+ */
+ ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq,
+ IRQF_TRIGGER_LOW | IRQF_SHARED |
+ IRQF_ONESHOT,
+ dev_name(dev), s);
+ if (!ret)
+ return 0;
+
ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq,
IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
dev_name(dev), s);
--
2.26.2
next prev parent reply other threads:[~2020-05-21 9:12 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-21 9:11 [PATCH v3 0/6] sc16is7xx: IrDA mode and threaded IRQs Daniel Mack
2020-05-21 9:11 ` [PATCH v3 1/6] dt-bindings: sc16is7xx: Add flag to activate IrDA mode Daniel Mack
2020-05-28 22:42 ` Rob Herring
2020-05-21 9:11 ` [PATCH v3 2/6] " Daniel Mack
2020-05-21 9:11 ` [PATCH v3 3/6] sc16is7xx: Always use falling edge IRQ Daniel Mack
2020-05-21 9:11 ` [PATCH v3 4/6] sc16is7xx: Use threaded IRQ Daniel Mack
2020-05-21 9:11 ` Daniel Mack [this message]
2020-05-21 9:11 ` [PATCH v3 6/6] sc16is7xx: Read the LSR register for basic device presence check Daniel Mack
2020-05-22 9:07 ` [PATCH v3 0/6] sc16is7xx: IrDA mode and threaded IRQs Greg KH
2020-05-23 12:27 ` Daniel Mack
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