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5b522e4969
This is an automatically generated commit which aids following Kernel patch history, as git will see the move and copy as a rename thus defeating the purpose. For the original discussion see: https://lists.openwrt.org/pipermail/openwrt-devel/2023-October/041673.html Signed-off-by: Martin Schiller <ms@dev.tdt.de>
63 lines
2.3 KiB
Diff
63 lines
2.3 KiB
Diff
From f038380835033e376d89c72516f087254792bbad Mon Sep 17 00:00:00 2001
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From: Martin Schiller <ms@dev.tdt.de>
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Date: Mon, 6 May 2024 09:41:42 +0200
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Subject: [PATCH] MIPS: pci: lantiq: restore reset gpio polarity
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Commit 90c2d2eb7ab5 ("MIPS: pci: lantiq: switch to using gpiod API") not
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only switched to the gpiod API, but also inverted / changed the polarity
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of the GPIO.
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According to the PCI specification, the RST# pin is an active-low
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signal. However, most of the device trees that have been widely used for
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a long time (mainly in the openWrt project) define this GPIO as
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active-high and the old driver code inverted the signal internally.
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Apparently there are actually boards where the reset gpio must be
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operated inverted. For this reason, we cannot use the GPIOD_OUT_LOW/HIGH
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flag for initialization. Instead, we must explicitly set the gpio to
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value 1 in order to take into account any "GPIO_ACTIVE_LOW" flag that
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may have been set.
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In order to remain compatible with all these existing device trees, we
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should therefore keep the logic as it was before the commit.
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Fixes: 90c2d2eb7ab5 ("MIPS: pci: lantiq: switch to using gpiod API")
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Cc: stable@vger.kernel.org
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Signed-off-by: Martin Schiller <ms@dev.tdt.de>
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---
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arch/mips/pci/pci-lantiq.c | 8 ++++----
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1 file changed, 4 insertions(+), 4 deletions(-)
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--- a/arch/mips/pci/pci-lantiq.c
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+++ b/arch/mips/pci/pci-lantiq.c
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@@ -124,14 +124,14 @@ static int ltq_pci_startup(struct platfo
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clk_disable(clk_external);
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/* setup reset gpio used by pci */
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- reset_gpio = devm_gpiod_get_optional(&pdev->dev, "reset",
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- GPIOD_OUT_LOW);
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+ reset_gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_ASIS);
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error = PTR_ERR_OR_ZERO(reset_gpio);
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if (error) {
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dev_err(&pdev->dev, "failed to request gpio: %d\n", error);
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return error;
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}
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gpiod_set_consumer_name(reset_gpio, "pci_reset");
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+ gpiod_direction_output(reset_gpio, 1);
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/* enable auto-switching between PCI and EBU */
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ltq_pci_w32(0xa, PCI_CR_CLK_CTRL);
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@@ -194,10 +194,10 @@ static int ltq_pci_startup(struct platfo
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/* toggle reset pin */
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if (reset_gpio) {
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- gpiod_set_value_cansleep(reset_gpio, 1);
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+ gpiod_set_value_cansleep(reset_gpio, 0);
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wmb();
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mdelay(1);
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- gpiod_set_value_cansleep(reset_gpio, 0);
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+ gpiod_set_value_cansleep(reset_gpio, 1);
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}
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return 0;
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}
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