The MT7531 reset pin is active-low, but several DTS files configured the reset-gpios property without GPIO_ACTIVE_LOW. This causes the reset GPIO to behave as active-high and prevents the switch from being properly reset. Update all affected DTS files to correctly use GPIO_ACTIVE_LOW so that the reset polarity matches the hardware design. Boards fixed: - mt7622-bananapi-bpi-r64 - mt7622-rfb1 - mt7986a-bananapi-bpi-r3 - mt7986a-rfb - mt7986b-rfb Note: the previous DTS description used the wrong polarity but the driver also assumed the opposite polarity, resulting in a matched pair of bugs that worked together. Updating the DTS requires updating the driver at the same time; old kernels will not reset the switch correctly when used with this DTS. Compatibility ------------- Correcting the polarity creates intentional incompatibility: * New kernel + old DTS: The driver now expects active-low, but out-of-tree DTS still marks active-high, causing the reset sequence to invert. * Old kernel + new DTS: The old driver toggles reset assuming active-high, which now conflicts with the corrected active-low DTS. This was unavoidable because the original DTS was factually wrong. Out-of-tree DTS users must update their DTS together with the kernel. Signed-off-by: Chen Minqiang --- arch/arm64/boot/dts/mediatek/mt7622-bananapi-bpi-r64.dts | 2 +- arch/arm64/boot/dts/mediatek/mt7622-rfb1.dts | 2 +- arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts | 2 +- arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts | 2 +- arch/arm64/boot/dts/mediatek/mt7986b-rfb.dts | 2 +- 5 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/arm64/boot/dts/mediatek/mt7622-bananapi-bpi-r64.dts b/arch/arm64/boot/dts/mediatek/mt7622-bananapi-bpi-r64.dts index 9f100b18a676..6f29ce828fdb 100644 --- a/arch/arm64/boot/dts/mediatek/mt7622-bananapi-bpi-r64.dts +++ b/arch/arm64/boot/dts/mediatek/mt7622-bananapi-bpi-r64.dts @@ -155,7 +155,7 @@ interrupt-controller; #interrupt-cells = <1>; interrupts-extended = <&pio 53 IRQ_TYPE_LEVEL_HIGH>; - reset-gpios = <&pio 54 0>; + reset-gpios = <&pio 54 GPIO_ACTIVE_LOW>; ports { #address-cells = <1>; diff --git a/arch/arm64/boot/dts/mediatek/mt7622-rfb1.dts b/arch/arm64/boot/dts/mediatek/mt7622-rfb1.dts index 8c3e2e2578bc..6600f06ccebf 100644 --- a/arch/arm64/boot/dts/mediatek/mt7622-rfb1.dts +++ b/arch/arm64/boot/dts/mediatek/mt7622-rfb1.dts @@ -137,7 +137,7 @@ switch@0 { compatible = "mediatek,mt7531"; reg = <0>; - reset-gpios = <&pio 54 0>; + reset-gpios = <&pio 54 GPIO_ACTIVE_LOW>; ports { #address-cells = <1>; diff --git a/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts b/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts index e7654dc9a1c9..8ec2ec78ee46 100644 --- a/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts +++ b/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts @@ -203,7 +203,7 @@ interrupt-parent = <&pio>; interrupts = <66 IRQ_TYPE_LEVEL_HIGH>; #interrupt-cells = <1>; - reset-gpios = <&pio 5 GPIO_ACTIVE_HIGH>; + reset-gpios = <&pio 5 GPIO_ACTIVE_LOW>; }; }; diff --git a/arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts b/arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts index 5d8e3d3f6c20..958ce291336b 100644 --- a/arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts +++ b/arch/arm64/boot/dts/mediatek/mt7986a-rfb.dts @@ -87,7 +87,7 @@ switch: switch@0 { compatible = "mediatek,mt7531"; reg = <31>; - reset-gpios = <&pio 5 0>; + reset-gpios = <&pio 5 1>; }; }; diff --git a/arch/arm64/boot/dts/mediatek/mt7986b-rfb.dts b/arch/arm64/boot/dts/mediatek/mt7986b-rfb.dts index 58f77d932429..0780b5a36259 100644 --- a/arch/arm64/boot/dts/mediatek/mt7986b-rfb.dts +++ b/arch/arm64/boot/dts/mediatek/mt7986b-rfb.dts @@ -64,7 +64,7 @@ switch@0 { compatible = "mediatek,mt7531"; reg = <31>; - reset-gpios = <&pio 5 0>; + reset-gpios = <&pio 5 1>; ports { #address-cells = <1>; -- 2.17.1 With GPIO_ACTIVE_LOW configured in DTS, gpiod_set_value(1) asserts reset (drives the line low), and gpiod_set_value(0) deasserts reset (drives high). Update the reset sequence so that the driver: - asserts reset by driving the GPIO low first - waits for the required reset interval - deasserts reset by driving it high This ensures MT7531 receives a correct low-to-high reset pulse. Compatibility notes: The previous implementation contained a polarity mismatch: the DTS described the reset line as active-high, while the driver asserted reset by driving the GPIO low. The two mistakes matched each other, so the reset sequence accidentally worked. This patch fixes both sides: the DTS is corrected to use GPIO_ACTIVE_LOW, and the driver now asserts reset by driving the line low (value = 1 for active-low) and then deasserts it by driving it high (value = 0). Because the old behaviour relied on a matched pair of bugs, this change is not compatible with mixed combinations of old DTS and new kernel, or new DTS and old kernel. Both sides must be updated together. Upstream DTS and upstream kernels will remain fully compatible after this patch. Out-of-tree DT blobs must update their reset-gpios flags to match the correct hardware polarity, or the switch may remain stuck in reset or fail to reset properly. There is no practical way to maintain compatibility with the previous incorrect behaviour without adding non-detectable heuristics, so fixing the binding and the driver together is the correct approach. Signed-off-by: Chen Minqiang --- drivers/net/dsa/mt7530.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c index 548b85befbf4..24c9adff191d 100644 --- a/drivers/net/dsa/mt7530.c +++ b/drivers/net/dsa/mt7530.c @@ -2405,9 +2405,9 @@ mt7530_setup(struct dsa_switch *ds) usleep_range(5000, 5100); reset_control_deassert(priv->rstc); } else { - gpiod_set_value_cansleep(priv->reset, 0); - usleep_range(5000, 5100); gpiod_set_value_cansleep(priv->reset, 1); + usleep_range(5000, 5100); + gpiod_set_value_cansleep(priv->reset, 0); } /* Waiting for MT7530 got to stable */ @@ -2643,9 +2643,9 @@ mt7531_setup(struct dsa_switch *ds) usleep_range(5000, 5100); reset_control_deassert(priv->rstc); } else { - gpiod_set_value_cansleep(priv->reset, 0); - usleep_range(5000, 5100); gpiod_set_value_cansleep(priv->reset, 1); + usleep_range(5000, 5100); + gpiod_set_value_cansleep(priv->reset, 0); } /* Waiting for MT7530 got to stable */ -- 2.17.1