[PATCH v3] gpiolib: Preserve desc->flags when setting state

[PATCH v3] gpiolib: Preserve desc->flags when setting state

[Chris Packham]

desc->flags may already have values set by of_gpiochip_add() so make
sure that this isn't undone when setting the initial direction.

Fixes: 3edfb7bd76bd1cba ("gpiolib: Show correct direction from the beginning")
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---

Notes:
    Changes in v2:
    - add braces to avoid ambiguious else warning
    Changes in v3:
    - clear the direction output in the negative case

 drivers/gpio/gpiolib.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e013d417a936..dbd1180316a0 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1392,12 +1392,17 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 	for (i = 0; i < chip->ngpio; i++) {
 		struct gpio_desc *desc = &gdev->descs[i];
 
-		if (chip->get_direction && gpiochip_line_is_valid(chip, i))
-			desc->flags = !chip->get_direction(chip, i) ?
-					(1 << FLAG_IS_OUT) : 0;
-		else
-			desc->flags = !chip->direction_input ?
-					(1 << FLAG_IS_OUT) : 0;
+		if (chip->get_direction && gpiochip_line_is_valid(chip, i)) {
+			if (!chip->get_direction(chip, i))
+				set_bit(FLAG_IS_OUT, &desc->flags);
+			else
+				clear_bit(FLAG_IS_OUT, &desc->flags);
+		} else {
+			if (!chip->direction_input)
+				set_bit(FLAG_IS_OUT, &desc->flags);
+			else
+				clear_bit(FLAG_IS_OUT, &desc->flags);
+		}
 	}
 
 	acpi_gpiochip_add(chip);
-- 
2.22.0

Re: [PATCH v3] gpiolib: Preserve desc->flags when setting state

[Linus Walleij]

On Sun, Jul 7, 2019 at 10:36 PM Chris Packham
<chris.packham@alliedtelesis.co.nz> wrote:

> desc->flags may already have values set by of_gpiochip_add() so make
> sure that this isn't undone when setting the initial direction.
>
> Fixes: 3edfb7bd76bd1cba ("gpiolib: Show correct direction from the beginning")
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>

Patch applied for fixes and tagged for stable.

Thanks for digging into this! Excellent work!

Yours,
Linus Walleij