drivers: tca8418: Change the interrupt type
diff mbox

Message ID 20161107144024.15291-1-maxime.ripard@free-electrons.com
State Under Review
Headers show

Commit Message

Maxime Ripard Nov. 7, 2016, 2:40 p.m. UTC
The TCA8418 interrupt has a level trigger, not a edge one.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 drivers/input/keyboard/tca8418_keypad.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Dmitry Torokhov Nov. 9, 2016, 12:04 a.m. UTC | #1
On Mon, Nov 07, 2016 at 03:40:24PM +0100, Maxime Ripard wrote:
> The TCA8418 interrupt has a level trigger, not a edge one.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Hmm, maybe we could rely on OF data for trigger type?

> ---
>  drivers/input/keyboard/tca8418_keypad.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/input/keyboard/tca8418_keypad.c b/drivers/input/keyboard/tca8418_keypad.c
> index 9002298698fc..b88b3696a2e1 100644
> --- a/drivers/input/keyboard/tca8418_keypad.c
> +++ b/drivers/input/keyboard/tca8418_keypad.c
> @@ -360,7 +360,7 @@ static int tca8418_keypad_probe(struct i2c_client *client,
>  		irq = gpio_to_irq(irq);
>  
>  	error = devm_request_threaded_irq(dev, irq, NULL, tca8418_irq_handler,
> -					  IRQF_TRIGGER_FALLING |
> +					  IRQF_TRIGGER_LOW |
>  						IRQF_SHARED |
>  						IRQF_ONESHOT,
>  					  client->name, keypad_data);
> -- 
> 2.10.1
>
Maxime Ripard Nov. 9, 2016, 8:02 a.m. UTC | #2
Hello Dmitry,

On Tue, Nov 08, 2016 at 04:04:00PM -0800, Dmitry Torokhov wrote:
> On Mon, Nov 07, 2016 at 03:40:24PM +0100, Maxime Ripard wrote:
> > The TCA8418 interrupt has a level trigger, not a edge one.
> > 
> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> 
> Hmm, maybe we could rely on OF data for trigger type?

We might, even though the i2c core doesn't change the trigger type
when it retrieves the interrupt from the DT.

However, I'm a bit worried about the other probing mechanims (ACPI,
board files) that should be supported as well, and removing the
trigger type from the flags might break those. There's no board files
using it though in the tree, but I don't know about ACPI systems.

Thanks,
Maxime
Dmitry Torokhov Nov. 10, 2016, 4:02 a.m. UTC | #3
Hi Maxime,

On Wed, Nov 09, 2016 at 09:02:35AM +0100, Maxime Ripard wrote:
> Hello Dmitry,
> 
> On Tue, Nov 08, 2016 at 04:04:00PM -0800, Dmitry Torokhov wrote:
> > On Mon, Nov 07, 2016 at 03:40:24PM +0100, Maxime Ripard wrote:
> > > The TCA8418 interrupt has a level trigger, not a edge one.
> > > 
> > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > 
> > Hmm, maybe we could rely on OF data for trigger type?
> 
> We might, even though the i2c core doesn't change the trigger type
> when it retrieves the interrupt from the DT.

i2c core itself does not, and should not, but irq code does:

of_irq_get() -> irq_create_of_mapping() -> irq_create_fwspec_mapping()
-> irqd_set_trigger_type().

> 
> However, I'm a bit worried about the other probing mechanims (ACPI,
> board files) that should be supported as well, and removing the
> trigger type from the flags might break those. There's no board files
> using it though in the tree, but I don't know about ACPI systems.

The driver is not enabled for ACPI systems, at least not in mainline.

By the way, this is what TCA8418 binding dochas to say:

"- interrupts: IRQ line number, should trigger on falling edge"

so it seems there was at least one system that needed falling edge and
not level interrupt.

Thanks.
Maxime Ripard Nov. 10, 2016, 9:13 a.m. UTC | #4
On Wed, Nov 09, 2016 at 08:02:08PM -0800, Dmitry Torokhov wrote:
> On Wed, Nov 09, 2016 at 09:02:35AM +0100, Maxime Ripard wrote:
> > Hello Dmitry,
> > 
> > On Tue, Nov 08, 2016 at 04:04:00PM -0800, Dmitry Torokhov wrote:
> > > On Mon, Nov 07, 2016 at 03:40:24PM +0100, Maxime Ripard wrote:
> > > > The TCA8418 interrupt has a level trigger, not a edge one.
> > > > 
> > > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > 
> > > Hmm, maybe we could rely on OF data for trigger type?
> > 
> > We might, even though the i2c core doesn't change the trigger type
> > when it retrieves the interrupt from the DT.
> 
> i2c core itself does not, and should not, but irq code does:
> 
> of_irq_get() -> irq_create_of_mapping() -> irq_create_fwspec_mapping()
> -> irqd_set_trigger_type().

Ah, indeed, I overlooked that. I wonder why platform_get_irq does it
then.

> 
> > 
> > However, I'm a bit worried about the other probing mechanims (ACPI,
> > board files) that should be supported as well, and removing the
> > trigger type from the flags might break those. There's no board files
> > using it though in the tree, but I don't know about ACPI systems.
> 
> The driver is not enabled for ACPI systems, at least not in mainline.

Ok. Good.

> By the way, this is what TCA8418 binding dochas to say:
> 
> "- interrupts: IRQ line number, should trigger on falling edge"
> 
> so it seems there was at least one system that needed falling edge and
> not level interrupt.

I don't know, looking at the datasheet, it really looks like it's
level triggered to me, and we were actually seeing issues when set in
edge.

http://www.ti.com/lit/ds/symlink/tca8418.pdf
Especially page 20 and 33.

My understanding is that in input, the chip will trigger on edges, but
the line coming from that device to the SoC will be level triggered.

Maxime
Dmitry Torokhov Nov. 12, 2016, 1:24 a.m. UTC | #5
On Thu, Nov 10, 2016 at 10:13:02AM +0100, Maxime Ripard wrote:
> On Wed, Nov 09, 2016 at 08:02:08PM -0800, Dmitry Torokhov wrote:
> > On Wed, Nov 09, 2016 at 09:02:35AM +0100, Maxime Ripard wrote:
> > > Hello Dmitry,
> > > 
> > > On Tue, Nov 08, 2016 at 04:04:00PM -0800, Dmitry Torokhov wrote:
> > > > On Mon, Nov 07, 2016 at 03:40:24PM +0100, Maxime Ripard wrote:
> > > > > The TCA8418 interrupt has a level trigger, not a edge one.
> > > > > 
> > > > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > > 
> > > > Hmm, maybe we could rely on OF data for trigger type?
> > > 
> > > We might, even though the i2c core doesn't change the trigger type
> > > when it retrieves the interrupt from the DT.
> > 
> > i2c core itself does not, and should not, but irq code does:
> > 
> > of_irq_get() -> irq_create_of_mapping() -> irq_create_fwspec_mapping()
> > -> irqd_set_trigger_type().
> 
> Ah, indeed, I overlooked that. I wonder why platform_get_irq does it
> then.
> 
> > 
> > > 
> > > However, I'm a bit worried about the other probing mechanims (ACPI,
> > > board files) that should be supported as well, and removing the
> > > trigger type from the flags might break those. There's no board files
> > > using it though in the tree, but I don't know about ACPI systems.
> > 
> > The driver is not enabled for ACPI systems, at least not in mainline.
> 
> Ok. Good.
> 
> > By the way, this is what TCA8418 binding dochas to say:
> > 
> > "- interrupts: IRQ line number, should trigger on falling edge"
> > 
> > so it seems there was at least one system that needed falling edge and
> > not level interrupt.
> 
> I don't know, looking at the datasheet, it really looks like it's
> level triggered to me, and we were actually seeing issues when set in
> edge.
> 
> http://www.ti.com/lit/ds/symlink/tca8418.pdf
> Especially page 20 and 33.
> 
> My understanding is that in input, the chip will trigger on edges, but
> the line coming from that device to the SoC will be level triggered.

The issue is that it is not necessarily connected directly to the
SoC/AP. It could be on a daughterboard with any number of converters,
possibly inverting polarity, or doing level->edge, etc. So the only sane
solution is to leave it to device tree to describe the setup to the
driver.

Thanks.

Patch
diff mbox

diff --git a/drivers/input/keyboard/tca8418_keypad.c b/drivers/input/keyboard/tca8418_keypad.c
index 9002298698fc..b88b3696a2e1 100644
--- a/drivers/input/keyboard/tca8418_keypad.c
+++ b/drivers/input/keyboard/tca8418_keypad.c
@@ -360,7 +360,7 @@  static int tca8418_keypad_probe(struct i2c_client *client,
 		irq = gpio_to_irq(irq);
 
 	error = devm_request_threaded_irq(dev, irq, NULL, tca8418_irq_handler,
-					  IRQF_TRIGGER_FALLING |
+					  IRQF_TRIGGER_LOW |
 						IRQF_SHARED |
 						IRQF_ONESHOT,
 					  client->name, keypad_data);