From: Hugo Villeneuve <hvilleneuve@dimonoff.com>

It's strongly recommended for GPIO drivers to always implement the
.get_direction() callback - even when the direction is tracked in
software. The GPIO core emits a warning when the callback is missing
and a user reads the direction of a line, e.g. via
/sys/kernel/debug/gpio.

Fixes: dfeae619d781 ("serial: sc16is7xx")
Cc: stable@kernel.org
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
---
Inspired by a similar patch for max310x: commit a483b1a91b33
("serial: max310x: implement gpio_chip::get_direction()").
---
 drivers/tty/serial/sc16is7xx.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 2498f9da2bf77..943be318de410 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1273,6 +1273,17 @@ static int sc16is7xx_gpio_set(struct gpio_chip *chip, unsigned int offset,
 	return 0;
 }
 
+static int sc16is7xx_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+	struct sc16is7xx_port *s = gpiochip_get_data(chip);
+	struct uart_port *port = &s->p[0].port;
+	unsigned int val;
+
+	val = sc16is7xx_port_read(port, SC16IS7XX_IODIR_REG);
+
+	return val & BIT(offset) ? GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
+}
+
 static int sc16is7xx_gpio_direction_input(struct gpio_chip *chip,
 					  unsigned offset)
 {
@@ -1350,6 +1361,7 @@ static int sc16is7xx_setup_gpio_chip(struct sc16is7xx_port *s)
 	s->gpio.parent		 = dev;
 	s->gpio.label		 = dev_name(dev);
 	s->gpio.init_valid_mask	 = sc16is7xx_gpio_init_valid_mask;
+	s->gpio.get_direction	 = sc16is7xx_gpio_get_direction;
 	s->gpio.direction_input	 = sc16is7xx_gpio_direction_input;
 	s->gpio.get		 = sc16is7xx_gpio_get;
 	s->gpio.direction_output = sc16is7xx_gpio_direction_output;

base-commit: da7b5fd4e17f8e44c5590f2d603c01d499f056e6
-- 
2.47.3

On Thu, Jul 16, 2026 at 11:08 PM Hugo Villeneuve <hugo@hugovil.com> wrote:

> From: Hugo Villeneuve <hvilleneuve@dimonoff.com>
>
> It's strongly recommended for GPIO drivers to always implement the
> .get_direction() callback - even when the direction is tracked in
> software. The GPIO core emits a warning when the callback is missing
> and a user reads the direction of a line, e.g. via
> /sys/kernel/debug/gpio.
>
> Fixes: dfeae619d781 ("serial: sc16is7xx")
> Cc: stable@kernel.org
> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>

Reviewed-by: Linus Walleij <linusw@kernel.org>

Yours,
Linus Walleij

On Thu, 16 Jul 2026 23:08:09 +0200, Hugo Villeneuve <hugo@hugovil.com> said:
> From: Hugo Villeneuve <hvilleneuve@dimonoff.com>
>
> It's strongly recommended for GPIO drivers to always implement the
> .get_direction() callback - even when the direction is tracked in
> software. The GPIO core emits a warning when the callback is missing
> and a user reads the direction of a line, e.g. via
> /sys/kernel/debug/gpio.
>
> Fixes: dfeae619d781 ("serial: sc16is7xx")
> Cc: stable@kernel.org
> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> ---
> Inspired by a similar patch for max310x: commit a483b1a91b33
> ("serial: max310x: implement gpio_chip::get_direction()").
> ---
>  drivers/tty/serial/sc16is7xx.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
> index 2498f9da2bf77..943be318de410 100644
> --- a/drivers/tty/serial/sc16is7xx.c
> +++ b/drivers/tty/serial/sc16is7xx.c
> @@ -1273,6 +1273,17 @@ static int sc16is7xx_gpio_set(struct gpio_chip *chip, unsigned int offset,
>  	return 0;
>  }
>
> +static int sc16is7xx_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
> +{
> +	struct sc16is7xx_port *s = gpiochip_get_data(chip);
> +	struct uart_port *port = &s->p[0].port;
> +	unsigned int val;
> +
> +	val = sc16is7xx_port_read(port, SC16IS7XX_IODIR_REG);
> +
> +	return val & BIT(offset) ? GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
> +}
> +
>  static int sc16is7xx_gpio_direction_input(struct gpio_chip *chip,
>  					  unsigned offset)
>  {
> @@ -1350,6 +1361,7 @@ static int sc16is7xx_setup_gpio_chip(struct sc16is7xx_port *s)
>  	s->gpio.parent		 = dev;
>  	s->gpio.label		 = dev_name(dev);
>  	s->gpio.init_valid_mask	 = sc16is7xx_gpio_init_valid_mask;
> +	s->gpio.get_direction	 = sc16is7xx_gpio_get_direction;
>  	s->gpio.direction_input	 = sc16is7xx_gpio_direction_input;
>  	s->gpio.get		 = sc16is7xx_gpio_get;
>  	s->gpio.direction_output = sc16is7xx_gpio_direction_output;
>
> base-commit: da7b5fd4e17f8e44c5590f2d603c01d499f056e6
> --
> 2.47.3
>
>

Acked-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>