[PATCH] gpiolib: acpi: Support GpioInt with active_low polarity

[PATCH] gpiolib: acpi: Support GpioInt with active_low polarity

[Ricardo Ribalda]

On the current implementation we only support active_high polarity for
GpioInt.

There can be cases where a GPIO has active_low polarity and it is also a
IRQ source.

De-couple the irq_polarity and active_low fields instead of re-use it.

With this patch we support ACPI devices such as:

Name (_CRS, ResourceTemplate ()  // _CRS: Current Resource Settings
{
        GpioInt (Edge, ActiveBoth, Exclusive, PullDefault, 0x0000,
        "\\_SB.PCI0.GPIO", 0x00, ResourceConsumer, ,
        )
        {   // Pin list
                0x0064
        }
})
Name (_DSD, Package (0x02)  // _DSD: Device-Specific Data
{
        ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301") /* Device Properties for _DSD */,
        Package (0x01)
        {
        Package (0x02)
        {
                "privacy-gpio",
                Package (0x04)
                {
                \_SB.PCI0.XHCI.RHUB.HS07,
                Zero,
                Zero,
                One
                }
        }
        }
})

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/gpio/gpiolib-acpi.c | 8 ++++----
 drivers/gpio/gpiolib-acpi.h | 6 ++++--
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 834a12f3219e..bc33c1056391 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -624,7 +624,7 @@ int acpi_gpio_update_gpiod_lookup_flags(unsigned long *lookupflags,
 		break;
 	}
 
-	if (info->polarity == GPIO_ACTIVE_LOW)
+	if (info->active_low)
 		*lookupflags |= GPIO_ACTIVE_LOW;
 
 	return 0;
@@ -665,6 +665,7 @@ static int acpi_populate_gpio_lookup(struct acpi_resource *ares, void *data)
 					      agpio->pin_table[pin_index]);
 		lookup->info.pin_config = agpio->pin_config;
 		lookup->info.gpioint = gpioint;
+		lookup->info.active_low = !!lookup->active_low;
 
 		/*
 		 * Polarity and triggering are only specified for GpioInt
@@ -675,11 +676,10 @@ static int acpi_populate_gpio_lookup(struct acpi_resource *ares, void *data)
 		 */
 		if (lookup->info.gpioint) {
 			lookup->info.flags = GPIOD_IN;
-			lookup->info.polarity = agpio->polarity;
+			lookup->info.irq_polarity = agpio->polarity;
 			lookup->info.triggering = agpio->triggering;
 		} else {
 			lookup->info.flags = acpi_gpio_to_gpiod_flags(agpio);
-			lookup->info.polarity = lookup->active_low;
 		}
 	}
 
@@ -958,7 +958,7 @@ int acpi_dev_gpio_irq_get(struct acpi_device *adev, int index)
 				return ret;
 
 			irq_flags = acpi_dev_get_irq_type(info.triggering,
-							  info.polarity);
+							  info.irq_polarity);
 
 			/* Set type if specified and different than the current one */
 			if (irq_flags != IRQ_TYPE_NONE &&
diff --git a/drivers/gpio/gpiolib-acpi.h b/drivers/gpio/gpiolib-acpi.h
index 1c6d65cf0629..816a2d7a21ed 100644
--- a/drivers/gpio/gpiolib-acpi.h
+++ b/drivers/gpio/gpiolib-acpi.h
@@ -16,7 +16,8 @@ struct acpi_device;
  * @flags: GPIO initialization flags
  * @gpioint: if %true this GPIO is of type GpioInt otherwise type is GpioIo
  * @pin_config: pin bias as provided by ACPI
- * @polarity: interrupt polarity as provided by ACPI
+ * @irq_polarity: interrupt polarity as provided by ACPI
+ * @active_low: pin polarity as provided by ACPI
  * @triggering: triggering type as provided by ACPI
  * @quirks: Linux specific quirks as provided by struct acpi_gpio_mapping
  */
@@ -25,7 +26,8 @@ struct acpi_gpio_info {
 	enum gpiod_flags flags;
 	bool gpioint;
 	int pin_config;
-	int polarity;
+	int irq_polarity;
+	bool active_low;
 	int triggering;
 	unsigned int quirks;
 };
-- 
2.29.0.rc2.309.g374f81d7ae-goog

Re: [PATCH] gpiolib: acpi: Support GpioInt with active_low polarity

[Ricardo Ribalda]

Hi Andy

On Thu, Oct 29, 2020 at 3:38 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Wed, Oct 28, 2020 at 06:17:57PM +0100, Ricardo Ribalda wrote:
> > On the current implementation we only support active_high polarity for
> > GpioInt.
> >
> > There can be cases where a GPIO has active_low polarity and it is also a
> > IRQ source.
> >
> > De-couple the irq_polarity and active_low fields instead of re-use it.
> >
> > With this patch we support ACPI devices such as:
>
> Is it real device on the market?!

Yes, it is a chromebook.

>
> This table is broken. _DSD GPIO active_low is only for GpioIo().

AFAIK the format of the _DSD is not in the ACPI standard. We have
decided its fields. (please correct me if I am wrong here)

On the other mail I have described why we need to make use of the
active_low on a GpioInt()

If there is another way of describing ActiveBoth + inverted polarity
please let me know and I will go that way.

Thanks

>
> If it is a ChromeBook, please fix the firmware.
>
> > Name (_CRS, ResourceTemplate ()  // _CRS: Current Resource Settings
> > {
> >         GpioInt (Edge, ActiveBoth, Exclusive, PullDefault, 0x0000,
> >         "\\_SB.PCI0.GPIO", 0x00, ResourceConsumer, ,
> >         )
> >         {   // Pin list
> >                 0x0064
> >         }
> > })
> > Name (_DSD, Package (0x02)  // _DSD: Device-Specific Data
> > {
> >         ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301") /* Device Properties for _DSD */,
> >         Package (0x01)
> >         {
> >         Package (0x02)
> >         {
> >                 "privacy-gpio",
> >                 Package (0x04)
> >                 {
> >                 \_SB.PCI0.XHCI.RHUB.HS07,
> >                 Zero,
> >                 Zero,
> >                 One
> >                 }
> >         }
> >         }
> > })
>
>
> --
> With Best Regards,
> Andy Shevchenko
>
>


-- 
Ricardo Ribalda

Re: [PATCH] gpiolib: acpi: Support GpioInt with active_low polarity

[Andy Shevchenko]

On Thu, Oct 29, 2020 at 5:37 PM Ricardo Ribalda <ribalda@google.com> wrote:
> On Thu, Oct 29, 2020 at 3:38 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> >
> > On Wed, Oct 28, 2020 at 06:17:57PM +0100, Ricardo Ribalda wrote:
> > > On the current implementation we only support active_high polarity for
> > > GpioInt.
> > >
> > > There can be cases where a GPIO has active_low polarity and it is also a
> > > IRQ source.
> > >
> > > De-couple the irq_polarity and active_low fields instead of re-use it.
> > >
> > > With this patch we support ACPI devices such as:
> >
> > Is it real device on the market?!
>
> Yes, it is a chromebook.

You mean it's already on sale with this broken table?!

> > This table is broken. _DSD GPIO active_low is only for GpioIo().
>
> AFAIK the format of the _DSD is not in the ACPI standard. We have
> decided its fields. (please correct me if I am wrong here)

_DSD is a concept that is part of the spec, but each UUID and its
application is out of scope indeed.

GPIO application to _DSD is described in the in-kernel documentation.
Thanks for pointing out the issues it has.

> On the other mail I have described why we need to make use of the
> active_low on a GpioInt()
>
> If there is another way of describing ActiveBoth + inverted polarity
> please let me know and I will go that way.

I answered it there, please, continue this topic there.
NAK to the proposed change.

> > If it is a ChromeBook, please fix the firmware.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] gpiolib: acpi: Support GpioInt with active_low polarity

[Ricardo Ribalda]

Adding Tomasz in CC in case he wants to share more info about the device.

On Thu, Oct 29, 2020 at 6:31 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Thu, Oct 29, 2020 at 5:37 PM Ricardo Ribalda <ribalda@google.com> wrote:
> > On Thu, Oct 29, 2020 at 3:38 PM Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> wrote:
> > >
> > > On Wed, Oct 28, 2020 at 06:17:57PM +0100, Ricardo Ribalda wrote:
> > > > On the current implementation we only support active_high polarity for
> > > > GpioInt.
> > > >
> > > > There can be cases where a GPIO has active_low polarity and it is also a
> > > > IRQ source.
> > > >
> > > > De-couple the irq_polarity and active_low fields instead of re-use it.
> > > >
> > > > With this patch we support ACPI devices such as:
> > >
> > > Is it real device on the market?!
> >
> > Yes, it is a chromebook.
>
> You mean it's already on sale with this broken table?!

I do not agree that it is broken.  It follows the current standard ;)

>
> > > This table is broken. _DSD GPIO active_low is only for GpioIo().
> >
> > AFAIK the format of the _DSD is not in the ACPI standard. We have
> > decided its fields. (please correct me if I am wrong here)
>
> _DSD is a concept that is part of the spec, but each UUID and its
> application is out of scope indeed.
>
> GPIO application to _DSD is described in the in-kernel documentation.
> Thanks for pointing out the issues it has.
>
> > On the other mail I have described why we need to make use of the
> > active_low on a GpioInt()
> >
> > If there is another way of describing ActiveBoth + inverted polarity
> > please let me know and I will go that way.
>
> I answered it there, please, continue this topic there.
> NAK to the proposed change.
>
> > > If it is a ChromeBook, please fix the firmware.

Lets agree what is the best way to describe in acpi my usecase and I
will implement it.

>
> --
> With Best Regards,
> Andy Shevchenko



-- 
Ricardo Ribalda

Re: [PATCH] gpiolib: acpi: Support GpioInt with active_low polarity

[Andy Shevchenko]

On Thu, Oct 29, 2020 at 8:09 PM Ricardo Ribalda <ribalda@google.com> wrote:
> Adding Tomasz in CC in case he wants to share more info about the device.

OK, but let's discuss in another thread.

-- 
With Best Regards,
Andy Shevchenko