On 23/02/2018 17:35, Andy Shevchenko wrote:
On Fri, 2018-02-23 at 02:42 +0800, John Garry wrote:
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.
It should be documented in the binding.
Agreed. I find the wording a bit ambigious in bindings/serial/8250.txt
and snps-dw-apb-uart.txt:
Required properties:
[...]
- interrupts : should contain uart interrupt.
It uses the word "should", and not "must". Maybe "should" means "must"...
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;
NO_IRQ _is_ 0. You need to do something like
if (irq < 0) }
... leave existing code ...
}
if (!irq)
dev_warn(, "Use polling mode\n");
OK
Thanks,
John
