Hello,
this is a set of patches I created while I tried to understand how DSA
works. I don't claim I already got there and so the first 3 fixes are
trivial only.
I tried to make the switch on the espressobin SBC use the interrupt line
and needed the fourth patch to make this work. Given I don't have access
to the documentation of the Marvell switch, the patch is probably not
correct though (and so doesn't have a S-o-b).
When I first added the irq as:
interrupt-parent = <&gpiosb>;
interrupts = <23 IRQ_TYPE_LEVEL_LOW>;
to the switch of the espressobin's dtb, the irq couldn't be used. The
reason is the interaction of several things:
- On the first try to probe the switch, the driver did:
irq = of_irq_get(np, 0);
request_threaded_irq(irq, NULL, func, IRQF_ONESHOT |
IRQF_TRIGGER_FALLING, ...);
and then later aborted with -EPROBE_DEFER because another resource
wasn't available yet. This correctly undid the request_threaded_irq
above using free_irq.
- When the probe routine was entered again, the call to of_irq_get(np, 0)
failed becauce the irq code remembered that the irq was requested
using edge triggered logic with:
irq: type mismatch, failed to map hwirq-23 for gpio!
(kernel/irq/irqdomain.c, line 801)
Any of the following changes would make the problem disappear:
- use IRQ_TYPE_EDGE_FALLING in the device tree;
- drop IRQF_TRIGGER_FALLING from the driver's use of
request_threaded_irq() (I think, see below); and
- make the irq code forget the trigger type when the last action is
removed
I think both the second and the third should be done.
For the third, after a quick look into kernel/irq I didn't find a
suitable place where to do that and so it would be great to get some
feedback from Marc or Thomas here.
Regarding the first one: Is the irq of the switch really edge sensitive?
I didn't see the line reset to 1 after an irq was triggered. (And again,
I don't have access on the documentation of the switch.) When I tested
the second change however the driver still failed because the
gpio controller doesn't support level sensitive irqs. :-|
Looking forward to your comments
Uwe Kleine-Köníg
Uwe Kleine-König (4):
net: dsa: mv88e6xxx: Fix name of switch 88E6141
net: dsa: mv88e6xxx: Fix typo in a comment
net: dsa: mv88e6xxx: Fix interrupt name for g2 irq
net: dsa: mv88e6xxx: Guess number of g1 irqs
drivers/net/dsa/mv88e6xxx/chip.c | 6 ++++--
drivers/net/dsa/mv88e6xxx/global2.c | 2 +-
2 files changed, 5 insertions(+), 3 deletions(-)
--
2.16.2
