diff mbox series

[v2,1/1] gpio: mpc8xxx: latch GPIOs state on module load when configured as output

Message ID 20230601230200.6128-2-msmulski2@gmail.com
State New
Headers show
Series gpio: mpc8xxx: latch GPIOs state on module load when configured as output | expand

Commit Message

msmulski2@gmail.com June 1, 2023, 11:02 p.m. UTC 
From: Michal Smulski <michal.smulski@ooma.com>

Qoriq and related devices allow reading out state of GPIO set as output.
However, currently on driver's init, all outputs are configured as driven
low. So, any changes to GPIO confiuration will drive all pins (configured
as output) as output-low.
This patch latches state of output GPIOs before any GPIO configuration
takes place. This preserves any output settings done prior to loading
the driver (for example, by u-boot).

Signed-off-by: Michal Smulski <michal.smulski@ooma.com>
---
 drivers/gpio/gpio-mpc8xxx.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Bartosz Golaszewski June 16, 2023, 9:11 a.m. UTC | #1 
On Fri, Jun 2, 2023 at 1:02 AM <msmulski2@gmail.com> wrote:
>
> From: Michal Smulski <michal.smulski@ooma.com>
>
> Qoriq and related devices allow reading out state of GPIO set as output.
> However, currently on driver's init, all outputs are configured as driven
> low. So, any changes to GPIO confiuration will drive all pins (configured
> as output) as output-low.
> This patch latches state of output GPIOs before any GPIO configuration
> takes place. This preserves any output settings done prior to loading
> the driver (for example, by u-boot).
>
> Signed-off-by: Michal Smulski <michal.smulski@ooma.com>
> ---
>  drivers/gpio/gpio-mpc8xxx.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
> index 3eb08cd1fdc0..6340e738c912 100644
> --- a/drivers/gpio/gpio-mpc8xxx.c
> +++ b/drivers/gpio/gpio-mpc8xxx.c
> @@ -375,8 +375,12 @@ static int mpc8xxx_probe(struct platform_device *pdev)
>         if (of_device_is_compatible(np, "fsl,qoriq-gpio") ||
>             of_device_is_compatible(np, "fsl,ls1028a-gpio") ||
>             of_device_is_compatible(np, "fsl,ls1088a-gpio") ||
> -           is_acpi_node(fwnode))
> +           is_acpi_node(fwnode)) {
>                 gc->write_reg(mpc8xxx_gc->regs + GPIO_IBE, 0xffffffff);
> +               /* Also, latch state of GPIOs configured as output by bootloader. */
> +               gc->bgpio_data = gc->read_reg(mpc8xxx_gc->regs + GPIO_DAT) &
> +                       gc->read_reg(mpc8xxx_gc->regs + GPIO_DIR);
> +       }
>
>         ret = devm_gpiochip_add_data(&pdev->dev, gc, mpc8xxx_gc);
>         if (ret) {
> --
> 2.34.1
>

Applied, thanks!

Bart
diff mbox series

Patch

diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
index 3eb08cd1fdc0..6340e738c912 100644
--- a/drivers/gpio/gpio-mpc8xxx.c
+++ b/drivers/gpio/gpio-mpc8xxx.c
@@ -375,8 +375,12 @@  static int mpc8xxx_probe(struct platform_device *pdev)
 	if (of_device_is_compatible(np, "fsl,qoriq-gpio") ||
 	    of_device_is_compatible(np, "fsl,ls1028a-gpio") ||
 	    of_device_is_compatible(np, "fsl,ls1088a-gpio") ||
-	    is_acpi_node(fwnode))
+	    is_acpi_node(fwnode)) {
 		gc->write_reg(mpc8xxx_gc->regs + GPIO_IBE, 0xffffffff);
+		/* Also, latch state of GPIOs configured as output by bootloader. */
+		gc->bgpio_data = gc->read_reg(mpc8xxx_gc->regs + GPIO_DAT) &
+			gc->read_reg(mpc8xxx_gc->regs + GPIO_DIR);
+	}
 
 	ret = devm_gpiochip_add_data(&pdev->dev, gc, mpc8xxx_gc);
 	if (ret) {