Patch "MIPS: pci: lantiq: restore reset gpio polarity" has been added to the 6.1-stable tree

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This is a note to let you know that I've just added the patch titled

    MIPS: pci: lantiq: restore reset gpio polarity

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mips-pci-lantiq-restore-reset-gpio-polarity.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 70543774444b6d583b13f58508b2d294e643b8b4
Author: Martin Schiller <ms@xxxxxxxxxx>
Date:   Fri Jun 7 11:04:00 2024 +0200

    MIPS: pci: lantiq: restore reset gpio polarity
    
    [ Upstream commit 277a0363120276645ae598d8d5fea7265e076ae9 ]
    
    Commit 90c2d2eb7ab5 ("MIPS: pci: lantiq: switch to using gpiod API") not
    only switched to the gpiod API, but also inverted / changed the polarity
    of the GPIO.
    
    According to the PCI specification, the RST# pin is an active-low
    signal. However, most of the device trees that have been widely used for
    a long time (mainly in the openWrt project) define this GPIO as
    active-high and the old driver code inverted the signal internally.
    
    Apparently there are actually boards where the reset gpio must be
    operated inverted. For this reason, we cannot use the GPIOD_OUT_LOW/HIGH
    flag for initialization. Instead, we must explicitly set the gpio to
    value 1 in order to take into account any "GPIO_ACTIVE_LOW" flag that
    may have been set.
    
    In order to remain compatible with all these existing device trees, we
    should therefore keep the logic as it was before the commit.
    
    Fixes: 90c2d2eb7ab5 ("MIPS: pci: lantiq: switch to using gpiod API")
    Cc: stable@xxxxxxxxxxxxxxx
    Signed-off-by: Martin Schiller <ms@xxxxxxxxxx>
    Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/mips/pci/pci-lantiq.c b/arch/mips/pci/pci-lantiq.c
index 8d16cd021f604..5c83f54341299 100644
--- a/arch/mips/pci/pci-lantiq.c
+++ b/arch/mips/pci/pci-lantiq.c
@@ -124,14 +124,14 @@ static int ltq_pci_startup(struct platform_device *pdev)
 		clk_disable(clk_external);
 
 	/* setup reset gpio used by pci */
-	reset_gpio = devm_gpiod_get_optional(&pdev->dev, "reset",
-					     GPIOD_OUT_LOW);
+	reset_gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_ASIS);
 	error = PTR_ERR_OR_ZERO(reset_gpio);
 	if (error) {
 		dev_err(&pdev->dev, "failed to request gpio: %d\n", error);
 		return error;
 	}
 	gpiod_set_consumer_name(reset_gpio, "pci_reset");
+	gpiod_direction_output(reset_gpio, 1);
 
 	/* enable auto-switching between PCI and EBU */
 	ltq_pci_w32(0xa, PCI_CR_CLK_CTRL);
@@ -194,10 +194,10 @@ static int ltq_pci_startup(struct platform_device *pdev)
 
 	/* toggle reset pin */
 	if (reset_gpio) {
-		gpiod_set_value_cansleep(reset_gpio, 1);
+		gpiod_set_value_cansleep(reset_gpio, 0);
 		wmb();
 		mdelay(1);
-		gpiod_set_value_cansleep(reset_gpio, 0);
+		gpiod_set_value_cansleep(reset_gpio, 1);
 	}
 	return 0;
 }




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