[RFC PATCH 2/2] serial: 8250_dw: support polling mode

John Garry
2018-02-22T17:49:55Z

It would be useful to make this driver support some
8250-compatible devices which have no interrupt line.

For these, we allow for no interrupt, and will fallback on
polling mode.

Note: the 8250 dt bindings state that "interrupts"
is a required property:
"interrupts : should contain uart interrupt."

But the 8250_of.c driver can live without it. So
this patch is going this way also.

Signed-off-by: John Garry <john.garry@huawei.com>
---
drivers/tty/serial/8250/8250_dw.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 28fbc8f..3154988 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -422,9 +422,10 @@ static int dw8250_probe(struct platform_device *pdev)
}

if (irq < 0) {
- if (irq != -EPROBE_DEFER)
- dev_err(dev, "cannot get irq\n");
- return irq;
+ if (irq == -EPROBE_DEFER)
+ return irq;
+ dev_warn(dev, "cannot get irq, using polling mode\n");
+ irq = 0;
}

spin_lock_init(&p->lock);
--
1.9.1