[PATCH] regmap: regmap-irq: Make irq-type callbak optional

[PATCH] regmap: regmap-irq: Make irq-type callbak optional

[Matti Vaittinen]

Do not register type setting callback if HW does not support
setting the irq type. IRQ core can then handle cases where
type setting is not supported and no regmap-irq specific handling
is required.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
---
 drivers/base/regmap/regmap-irq.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index d2d0014b0d23..a387ee499b5c 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -322,7 +322,6 @@ static const struct irq_chip regmap_irq_chip = {
 	.irq_bus_sync_unlock	= regmap_irq_sync_unlock,
 	.irq_disable		= regmap_irq_disable,
 	.irq_enable		= regmap_irq_enable,
-	.irq_set_type		= regmap_irq_set_type,
 	.irq_set_wake		= regmap_irq_set_wake,
 };
 
@@ -560,6 +559,9 @@ int regmap_add_irq_chip(struct regmap *map, int irq, int irq_flags,
 	d->chip = chip;
 	d->irq_base = irq_base;
 
+	if (num_type_reg)
+		d->irq_chip.irq_set_type = regmap_irq_set_type;
+
 	if (chip->irq_reg_stride)
 		d->irq_reg_stride = chip->irq_reg_stride;
 	else
-- 
2.14.3


-- 
Matti Vaittinen
ROHM Semiconductors

~~~ "I don't think so," said Rene Descartes.  Just then, he vanished ~~~

Re: [PATCH] regmap: regmap-irq: Make irq-type callbak optional

[Charles Keepax]

On Fri, Jan 04, 2019 at 12:31:15PM +0200, Matti Vaittinen wrote:
> Do not register type setting callback if HW does not support
> setting the irq type. IRQ core can then handle cases where
> type setting is not supported and no regmap-irq specific handling
> is required.
> 
> Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
> ---
>  drivers/base/regmap/regmap-irq.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
> index d2d0014b0d23..a387ee499b5c 100644
> --- a/drivers/base/regmap/regmap-irq.c
> +++ b/drivers/base/regmap/regmap-irq.c
> @@ -322,7 +322,6 @@ static const struct irq_chip regmap_irq_chip = {
>  	.irq_bus_sync_unlock	= regmap_irq_sync_unlock,
>  	.irq_disable		= regmap_irq_disable,
>  	.irq_enable		= regmap_irq_enable,
> -	.irq_set_type		= regmap_irq_set_type,
>  	.irq_set_wake		= regmap_irq_set_wake,
>  };
>  
> @@ -560,6 +559,9 @@ int regmap_add_irq_chip(struct regmap *map, int irq, int irq_flags,
>  	d->chip = chip;
>  	d->irq_base = irq_base;
>  
> +	if (num_type_reg)
> +		d->irq_chip.irq_set_type = regmap_irq_set_type;
> +
>  	if (chip->irq_reg_stride)
>  		d->irq_reg_stride = chip->irq_reg_stride;
>  	else

Afraid this also causes regressions at my end, still having a bit
of a look but it looks like some how this prevents properties of the
IRQ getting passed along which causes my system to not probe
properly with:

genirq: Flags mismatch irq 58. 00002088 (cs35l35) vs. 00002088 (cs35l35)
cs35l35 0-0041: Failed to request IRQ: -16

Thanks,
Charles

> -- 
> 2.14.3
> 
> 
> -- 
> Matti Vaittinen
> ROHM Semiconductors
> 
> ~~~ "I don't think so," said Rene Descartes.  Just then, he vanished ~~~

Re: [PATCH] regmap: regmap-irq: Make irq-type callbak optional

[Charles Keepax]

On Fri, Jan 04, 2019 at 11:14:43AM +0000, Charles Keepax wrote:
> On Fri, Jan 04, 2019 at 12:31:15PM +0200, Matti Vaittinen wrote:
> > +	if (num_type_reg)
> > +		d->irq_chip.irq_set_type = regmap_irq_set_type;
> > +
> 
> Afraid this also causes regressions at my end, still having a bit
> of a look but it looks like some how this prevents properties of the
> IRQ getting passed along which causes my system to not probe
> properly with:
> 
> genirq: Flags mismatch irq 58. 00002088 (cs35l35) vs. 00002088 (cs35l35)
> cs35l35 0-0041: Failed to request IRQ: -16
> 

My case is a shared IRQ with 2 amps (cs35l35) connected to a CODEC
(wm8280).

So looks like the issue is if you don't have a set_type callback
then the IRQ ends up as IRQF_TRIGGER_NONE, which causes the
second IRQ to fail the middle check here in __setup_irq:

		if (!((old->flags & new->flags) & IRQF_SHARED) ||
		    (oldtype != (new->flags & IRQF_TRIGGER_MASK)) ||
		    ((old->flags ^ new->flags) & IRQF_ONESHOT)) {

Kinda inclined to just leave the fix as currently submitted and
just drop this patch? But I can do more testing etc. if we want
to push further down this road.

Thanks,
Charles

Re: [PATCH] regmap: regmap-irq: Make irq-type callbak optional

[Matti Vaittinen]

Big thanks for testing this so early Charles =) It's nice to get this
report before I broke things more widely!

On Fri, Jan 04, 2019 at 11:32:07AM +0000, Charles Keepax wrote:
> On Fri, Jan 04, 2019 at 11:14:43AM +0000, Charles Keepax wrote:
> > On Fri, Jan 04, 2019 at 12:31:15PM +0200, Matti Vaittinen wrote:
> > > +	if (num_type_reg)
> > > +		d->irq_chip.irq_set_type = regmap_irq_set_type;
> > > +
> > 
> > Afraid this also causes regressions at my end, still having a bit
> > of a look but it looks like some how this prevents properties of the
> > IRQ getting passed along which causes my system to not probe
> > properly with:
> > 
> > genirq: Flags mismatch irq 58. 00002088 (cs35l35) vs. 00002088 (cs35l35)
> > cs35l35 0-0041: Failed to request IRQ: -16
> > 
> 
> My case is a shared IRQ with 2 amps (cs35l35) connected to a CODEC
> (wm8280).
> 
> So looks like the issue is if you don't have a set_type callback
> then the IRQ ends up as IRQF_TRIGGER_NONE, which causes the
> second IRQ to fail the middle check here in __setup_irq:
> 
> 		if (!((old->flags & new->flags) & IRQF_SHARED) ||
> 		    (oldtype != (new->flags & IRQF_TRIGGER_MASK)) ||
> 		    ((old->flags ^ new->flags) & IRQF_ONESHOT)) {

Right. Thanks for pinpointing the issue. This thing is a bit fishy.
There should not be a need for a 'fake type setting callback' when we
have shared IRQ with two or more devices who actually agree on IRQ type
- assuming the HW default irq type is correct.

For me the correct thing would that the HW default type should be
stored in desc and returned by irqd_get_trigger_type instead of
IRQF_TRIGGER_NONE. But I have no idea how that would be nicely
implemented w/o going trough all the irqchips.

The other option would be being more permissive when IRQF_TRIGGER_NONE
is set as oldtype. But I am not feeling like an expert on this area.

> Kinda inclined to just leave the fix as currently submitted and
> just drop this patch? But I can do more testing etc. if we want
> to push further down this road.

Huge thanks for the offer Charles - I do really appreciate the testing.
Touching the IRQ core sounds quite scary to me. Changing it feels risky
and would probably involve bunch of other people too. 10-years ago I
would have taken the challenge and tried to get this "correct" - but
nowadays I have learned to accept some small shortcuts :p

I will gladly follow things and participate the discussions/development
if someone wants to see how this should be done - but I don't think I
have the energy and time to drive this change further... So Mark, please
just drop this patch and keep the original fix unless you want to drive
this further yourself =)


Br,
	Matti Vaittinen

> 
> Thanks,
> Charles

-- 
Matti Vaittinen
ROHM Semiconductors

~~~ "I don't think so," said Rene Descartes.  Just then, he vanished ~~~