[PATCH] arm64: dts: qcom: qcs6490-rb3gen2: Increase MCP2518FD SPI frequency to 17MHz

From: Viken Dadhaniya

Date: Mon Aug 10 2026 - 14:33:31 EST


The MCP2518FD CAN controller is limited to 14MHz because higher SPI
frequencies are unreliable with the current SPI3 pin drive strength.

Set the SPI3 data, clock and chip-select lines to 8mA drive strength and
raise spi-max-frequency to 17MHz, the maximum allowed by the MCP2518FD
errata:

0.85 * Fosc / 2 = 0.85 * 40MHz / 2 = 17MHz

Signed-off-by: Viken Dadhaniya <viken.dadhaniya@xxxxxxxxxxxxxxxx>
---
arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
index 90f2eebc349f..eb8d83317f36 100644
--- a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
+++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
@@ -1105,6 +1105,16 @@ &pon_resin {
status = "okay";
};

+&qup_spi3_cs {
+ drive-strength = <8>;
+ bias-disable;
+};
+
+&qup_spi3_data_clk {
+ drive-strength = <8>;
+ bias-disable;
+};
+
&qup_uart7_cts {
/*
* Configure a bias-bus-hold on CTS to lower power
@@ -1233,7 +1243,7 @@ can@0 {
reg = <0>;
interrupts-extended = <&tlmm 7 IRQ_TYPE_LEVEL_LOW>;
clocks = <&mcp2518fd_osc>;
- spi-max-frequency = <14000000>;
+ spi-max-frequency = <17000000>;
vdd-supply = <&vreg_l11c_2p8>;
microchip,xstbyen;
};

---
base-commit: 0f6da28aab51b16762ed82e8fdeaa5042da45b08
change-id: 20260810-kodiak-spi-can-17mhz-freq-c831e1893af8

Best regards,
--
Viken Dadhaniya <viken.dadhaniya@xxxxxxxxxxxxxxxx>