[PATCH] PCI: apple: Avoid PERST# deassertion through gpiod initialization

[PATCH] PCI: apple: Avoid PERST# deassertion through gpiod initialization

[Janne Grunau]

Commit 87620512681a ("PCI: apple: Fix PERST# polarity") switched the
PERST# polarity by annotaing its GPIO as active low in the device tree
via [1]. It missed to update gpiod_get()'s flags to GPIOD_OUT_HIGH
resulting in deasserting PERST# through gpiod initialization.
The Aquantia AQC113 10GB ethernet device used in some Apple silicon
desktop does not finish link training with this additional PERST#
deassert before the usual PERST# dance.

Link: https://lore.kernel.org/linux-pci/20211123180636.80558-1-maz@kernel.org/ [1]
Fixes: 87620512681a ("PCI: apple: Fix PERST# polarity")
Cc: stable@vger.kernel.org
Signed-off-by: Janne Grunau <j@jannau.net>
---
This issue affects only a single PCIe devices of the handful of built-in
devices integrated in Apple silicon devices. It is usually hidden by
u-boot's initialisation of PCIe devices.
---
 drivers/pci/controller/pcie-apple.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
index c2cffc0659f4..a7f327803060 100644
--- a/drivers/pci/controller/pcie-apple.c
+++ b/drivers/pci/controller/pcie-apple.c
@@ -562,7 +562,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
 	int ret, i;
 
 	reset = devm_fwnode_gpiod_get(pcie->dev, of_fwnode_handle(np), "reset",
-				      GPIOD_OUT_LOW, "PERST#");
+				      GPIOD_OUT_HIGH, "PERST#");
 	if (IS_ERR(reset))
 		return PTR_ERR(reset);
 

---
base-commit: c03c1a14507dfaf8b856c2608f9ac216021fc222
change-id: 20261024-pcie-apple-perst-gpiod-init-b602ee4dca46

Best regards,
-- 
Janne Grunau <j@jannau.net>

Re: [PATCH] PCI: apple: Avoid PERST# deassertion through gpiod initialization

[Marc Zyngier]

On Sat, 24 Oct 2026 17:46:54 +0100,
Janne Grunau <j@jannau.net> wrote:
> 
> Commit 87620512681a ("PCI: apple: Fix PERST# polarity") switched the
> PERST# polarity by annotaing its GPIO as active low in the device tree
> via [1]. It missed to update gpiod_get()'s flags to GPIOD_OUT_HIGH
> resulting in deasserting PERST# through gpiod initialization.
> The Aquantia AQC113 10GB ethernet device used in some Apple silicon
> desktop does not finish link training with this additional PERST#
> deassert before the usual PERST# dance.
> 
> Link: https://lore.kernel.org/linux-pci/20211123180636.80558-1-maz@kernel.org/ [1]
> Fixes: 87620512681a ("PCI: apple: Fix PERST# polarity")
> Cc: stable@vger.kernel.org
> Signed-off-by: Janne Grunau <j@jannau.net>
> ---
> This issue affects only a single PCIe devices of the handful of built-in
> devices integrated in Apple silicon devices. It is usually hidden by
> u-boot's initialisation of PCIe devices.
> ---
>  drivers/pci/controller/pcie-apple.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
> index c2cffc0659f4..a7f327803060 100644
> --- a/drivers/pci/controller/pcie-apple.c
> +++ b/drivers/pci/controller/pcie-apple.c
> @@ -562,7 +562,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
>  	int ret, i;
>  
>  	reset = devm_fwnode_gpiod_get(pcie->dev, of_fwnode_handle(np), "reset",
> -				      GPIOD_OUT_LOW, "PERST#");
> +				      GPIOD_OUT_HIGH, "PERST#");
>  	if (IS_ERR(reset))
>  		return PTR_ERR(reset);
>  
> 

Acked-by: Marc Zyngier <maz@kernel.org>

	M.

-- 
Without deviation from the norm, progress is not possible.