From: Rong Zhang Date: Sun, 15 Mar 2026 18:44:00 +0000 (+0800) Subject: MIPS: dts: loongson64g-package: Switch to Loongson UART driver X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=79b888ee4c6387bc07c5452bfd031cb985871a5f;p=thirdparty%2Fkernel%2Flinux.git MIPS: dts: loongson64g-package: Switch to Loongson UART driver Loongson64g is Loongson 3A4000, whose UART controller is compatible with Loongson 2K1500, which is NS16550A-compatible with an additional fractional frequency divisor register. Update the compatible strings to reflect this, so that 3A4000 can benefit from the fractional frequency divisor provided by loongson-uart. This is required on some devices, otherwise their UART can't work at some high baud rates, e.g., 115200. Tested on Loongson-LS3A4000-7A1000-NUC-SE with a 25MHz UART clock. Without fractional frequency divisor, the actual baud rate was 111607 (25MHz / 16 / 14, measured value: 111545) and some USB-to-UART converters couldn't work with it at all. With fractional frequency divisor, the measured baud rate becomes 115207, which is quite accurate. Signed-off-by: Rong Zhang Signed-off-by: Thomas Bogendoerfer --- diff --git a/arch/mips/boot/dts/loongson/loongson64g-package.dtsi b/arch/mips/boot/dts/loongson/loongson64g-package.dtsi index d4314f62ccc20..029daeedd0ab6 100644 --- a/arch/mips/boot/dts/loongson/loongson64g-package.dtsi +++ b/arch/mips/boot/dts/loongson/loongson64g-package.dtsi @@ -40,7 +40,7 @@ }; cpu_uart0: serial@1fe00100 { - compatible = "ns16550a"; + compatible = "loongson,ls3a4000-uart", "loongson,ls2k1500-uart", "ns16550a"; reg = <0 0x1fe00100 0x10>; clock-frequency = <100000000>; interrupt-parent = <&liointc>; @@ -50,7 +50,7 @@ cpu_uart1: serial@1fe00110 { status = "disabled"; - compatible = "ns16550a"; + compatible = "loongson,ls3a4000-uart", "loongson,ls2k1500-uart", "ns16550a"; reg = <0 0x1fe00110 0x10>; clock-frequency = <100000000>; interrupts = <15 IRQ_TYPE_LEVEL_HIGH>;