From: Helmut Klein <hgkr.kl...@gmail.com> Add the documentation for the device tree binding of Amlogic Meson Serial UART.
Signed-off-by: Helmut Klein <hgkr.kl...@gmail.com> Signed-off-by: Neil Armstrong <narmstr...@baylibre.com> --- .../bindings/serial/amlogic,meson-uart.txt | 38 ++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 Documentation/devicetree/bindings/serial/amlogic,meson-uart.txt diff --git a/Documentation/devicetree/bindings/serial/amlogic,meson-uart.txt b/Documentation/devicetree/bindings/serial/amlogic,meson-uart.txt new file mode 100644 index 0000000..8ff65fa --- /dev/null +++ b/Documentation/devicetree/bindings/serial/amlogic,meson-uart.txt @@ -0,0 +1,38 @@ +Amlogic Meson SoC UART Serial Interface +======================================= + +The Amlogic Meson SoC UART Serial Interface is present on a large range +of SoCs, and can be present either in the "Always-On" power domain or the +"Everything-Else" power domain. + +The particularity of the "Always-On" Serial Interface is that the hardware +is active since power-on and does not need any clock gating and is usable +as very early serial console. + +Required properties: +- compatible : compatible: value should be different for each SoC family as : + - Meson6 : "amlogic,meson6-uart" + - Meson8 : "amlogic,meson8-uart" + - Meson8b : "amlogic,meson8b-uart" + - GX (GXBB, GXL, GXM) : "amlogic,meson-gx-uart" + eventually followed by : "amlogic,meson-ao-uart" if this UART interface + is in the "Always-On" power domain. +- reg : offset and length of the register set for the device. +- interrupts : identifier to the device interrupt +- clocks : a list of phandle + clock-specifier pairs, one for each + entry in clock names. +- clocks-names : + * "xtal" for external xtal clock identifier + * "pclk" for the bus core clock, either the clk81 clock or the gate clock + * "baud" for the source of the baudrate generator, can be either the xtal + or the pclk. + +e.g. +uart_A: serial@84c0 { + compatible = "amlogic,meson-gx-uart"; + reg = <0x0 0x84c0 0x0 0x14>; + interrupts = <GIC_SPI 26 IRQ_TYPE_EDGE_RISING>; + /* Use xtal as baud rate clock source */ + clocks = <&xtal>, <&clkc CLKID_UART0>, <&xtal>; + clock-names = "xtal", "pclk", "baud"; +}; -- 1.9.1