[RFC PATCH] gpio/acpi: set direction for ACPI OpRegion GPIOs

[RFC PATCH] gpio/acpi: set direction for ACPI OpRegion GPIOs

[Ard Biesheuvel]

The ACPI GPIO OpRegion code never sets the direction for GPIOs that
it configures from scratch, leaving unconfigured GPIOs to be left
at the default direction, which is typically input not output.

So set the direction and default value explicitly.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/gpio/gpiolib-acpi.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index c9fc9e232aaf..02a2bc7fe18b 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -966,6 +966,12 @@ acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
 				goto out;
 			}
 
+			if (function == ACPI_WRITE)
+				gpiod_direction_output(desc,
+						       !!((1 << i) & *value));
+			else
+				gpiod_direction_input(desc);
+
 			conn->pin = pin;
 			conn->desc = desc;
 			list_add_tail(&conn->node, &achip->conns);
-- 
2.20.1

Re: [RFC PATCH] gpio/acpi: set direction for ACPI OpRegion GPIOs

[Mika Westerberg]

On Wed, May 29, 2019 at 12:13:42PM +0200, Ard Biesheuvel wrote:
> The ACPI GPIO OpRegion code never sets the direction for GPIOs that
> it configures from scratch, leaving unconfigured GPIOs to be left
> at the default direction, which is typically input not output.

The code does:

  enum gpiod_flags flags = acpi_gpio_to_gpiod_flags(agpio);

before it requests the GPIO. Isn't that sufficient?

Re: [RFC PATCH] gpio/acpi: set direction for ACPI OpRegion GPIOs

[Ard Biesheuvel]

On Wed, 29 May 2019 at 12:27, Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:
>
> On Wed, May 29, 2019 at 12:13:42PM +0200, Ard Biesheuvel wrote:
> > The ACPI GPIO OpRegion code never sets the direction for GPIOs that
> > it configures from scratch, leaving unconfigured GPIOs to be left
> > at the default direction, which is typically input not output.
>
> The code does:
>
>   enum gpiod_flags flags = acpi_gpio_to_gpiod_flags(agpio);
>
> before it requests the GPIO. Isn't that sufficient?

Yes, it works if I set the PullXxx value explicitly in the GpioIo() resource.