[PATCH 0/2] arm: dts: lpc32xx: Specify compatibility of platform UARTs with 16550A

[PATCH 0/2] arm: dts: lpc32xx: Specify compatibility of platform UARTs with 16550A

[Vladimir Zapolskiy]

NXP LPC32xx SoC has 4 16550A compatible UARTs with 64 byte TX and RX FIFO
sizes, and the platform UART hardware is well supported as a standard
16550A UART.

Vladimir Zapolskiy (2):
  dt-bindings: serial: 8250: Explicitly make LPC32xx UARTs compatible with 16550A
  arm: dts: lpc32xx: Add ns16550a compatible value to UART device tree nodes

 Documentation/devicetree/bindings/serial/8250.yaml | 2 +-
 arch/arm/boot/dts/nxp/lpc/lpc32xx.dtsi             | 9 ++++-----
 2 files changed, 5 insertions(+), 6 deletions(-)

-- 
2.43.0

[PATCH 1/2] dt-bindings: serial: 8250: Explicitly make LPC32xx UARTs compatible with 16550A

[Vladimir Zapolskiy]

NXP LPC32xx SoC has 4 16550A compatible UARTs with 64 byte TX and RX FIFO
sizes, and the platform UART hardware is well supported as a standard
16550A UART.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
---
 Documentation/devicetree/bindings/serial/8250.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/serial/8250.yaml b/Documentation/devicetree/bindings/serial/8250.yaml
index 167ddcbd8800..1a5178320465 100644
--- a/Documentation/devicetree/bindings/serial/8250.yaml
+++ b/Documentation/devicetree/bindings/serial/8250.yaml
@@ -108,7 +108,6 @@ properties:
       - const: nuvoton,wpcm450-uart
       - const: nuvoton,npcm750-uart
       - const: nvidia,tegra20-uart
-      - const: nxp,lpc3220-uart
       - items:
           - enum:
               - exar,xr16l2552
@@ -123,6 +122,7 @@ properties:
               - fsl,16550-FIFO64
               - andestech,uart16550
               - nxp,lpc1850-uart
+              - nxp,lpc3220-uart
               - opencores,uart16550-rtlsvn105
               - ti,da830-uart
               - loongson,ls2k0500-uart
-- 
2.43.0

Re: [PATCH 1/2] dt-bindings: serial: 8250: Explicitly make LPC32xx UARTs compatible with 16550A

[Krzysztof Kozlowski]

On Sat, Jan 10, 2026 at 04:46:46AM +0200, Vladimir Zapolskiy wrote:
> NXP LPC32xx SoC has 4 16550A compatible UARTs with 64 byte TX and RX FIFO
> sizes, and the platform UART hardware is well supported as a standard
> 16550A UART.

Driver uses dedicated driver/match data, so some context here about
compatibility would be useful.

Best regards,
Krzysztof

Re: [PATCH 1/2] dt-bindings: serial: 8250: Explicitly make LPC32xx UARTs compatible with 16550A

[Vladimir Zapolskiy]

On 1/12/26 11:25, Krzysztof Kozlowski wrote:
> On Sat, Jan 10, 2026 at 04:46:46AM +0200, Vladimir Zapolskiy wrote:
>> NXP LPC32xx SoC has 4 16550A compatible UARTs with 64 byte TX and RX FIFO
>> sizes, and the platform UART hardware is well supported as a standard
>> 16550A UART.
> 
> Driver uses dedicated driver/match data, so some context here about
> compatibility would be useful.
> 

As the commit message says, 4 LPC32xx UARTs are NS16550A compatible, this
is the context of the change.

Any bootloader or operating system which does not locate "nxp,lpc3220-uart"
device driver shall use the general "ns16550" compatible device driver.

-- 
Best wishes,
Vladimir

[PATCH 2/2] arm: dts: lpc32xx: Add ns16550a compatible value to UART device tree nodes

[Vladimir Zapolskiy]

NXP LPC32xx SoC has 4 16550A compatible UARTs with a difference of minor
significance, which is expectedly handled in the 8250 serial driver.

Reflect this fact in the platform device tree file by adding the expected
compatible value.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
---
 arch/arm/boot/dts/nxp/lpc/lpc32xx.dtsi | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/arm/boot/dts/nxp/lpc/lpc32xx.dtsi b/arch/arm/boot/dts/nxp/lpc/lpc32xx.dtsi
index e94df78def18..8fa1848943f8 100644
--- a/arch/arm/boot/dts/nxp/lpc/lpc32xx.dtsi
+++ b/arch/arm/boot/dts/nxp/lpc/lpc32xx.dtsi
@@ -263,8 +263,7 @@ i2s1: i2s@2009c000 {
 
 			/* UART5 first since it is the default console, ttyS0 */
 			uart5: serial@40090000 {
-				/* actually, ns16550a w/ 64 byte fifos! */
-				compatible = "nxp,lpc3220-uart";
+				compatible = "nxp,lpc3220-uart", "ns16550a";
 				reg = <0x40090000 0x1000>;
 				interrupts = <9 IRQ_TYPE_LEVEL_HIGH>;
 				reg-shift = <2>;
@@ -273,7 +272,7 @@ uart5: serial@40090000 {
 			};
 
 			uart3: serial@40080000 {
-				compatible = "nxp,lpc3220-uart";
+				compatible = "nxp,lpc3220-uart", "ns16550a";
 				reg = <0x40080000 0x1000>;
 				interrupts = <7 IRQ_TYPE_LEVEL_HIGH>;
 				reg-shift = <2>;
@@ -282,7 +281,7 @@ uart3: serial@40080000 {
 			};
 
 			uart4: serial@40088000 {
-				compatible = "nxp,lpc3220-uart";
+				compatible = "nxp,lpc3220-uart", "ns16550a";
 				reg = <0x40088000 0x1000>;
 				interrupts = <8 IRQ_TYPE_LEVEL_HIGH>;
 				reg-shift = <2>;
@@ -291,7 +290,7 @@ uart4: serial@40088000 {
 			};
 
 			uart6: serial@40098000 {
-				compatible = "nxp,lpc3220-uart";
+				compatible = "nxp,lpc3220-uart", "ns16550a";
 				reg = <0x40098000 0x1000>;
 				interrupts = <10 IRQ_TYPE_LEVEL_HIGH>;
 				reg-shift = <2>;
-- 
2.43.0