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Document a set of generic properties for describing UARTs in a
device tree:
1. The GPIO modem control properties are currently duplicated across
hardware-specific binding documentation,
2. The property for dedicated RTS/CTS hardware flow control lines is
already supported by several drivers, albeit with a vendor-specific
prefix, hence make it generic.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <rob@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
58 lines
2.1 KiB
Plaintext
58 lines
2.1 KiB
Plaintext
Generic Serial DT Bindings
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This document lists a set of generic properties for describing UARTs in a
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device tree. Whether these properties apply to a particular device depends on
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the DT bindings for the actual device.
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Optional properties:
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- cts-gpios: Must contain a GPIO specifier, referring to the GPIO pin to be
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used as the UART's CTS line.
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- dcd-gpios: Must contain a GPIO specifier, referring to the GPIO pin to be
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used as the UART's DCD line.
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- dsr-gpios: Must contain a GPIO specifier, referring to the GPIO pin to be
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used as the UART's DSR line.
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- dtr-gpios: Must contain a GPIO specifier, referring to the GPIO pin to be
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used as the UART's DTR line.
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- rng-gpios: Must contain a GPIO specifier, referring to the GPIO pin to be
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used as the UART's RNG line.
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- rts-gpios: Must contain a GPIO specifier, referring to the GPIO pin to be
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used as the UART's RTS line.
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- uart-has-rtscts: The presence of this property indicates that the
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UART has dedicated lines for RTS/CTS hardware flow control, and that
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they are available for use (wired and enabled by pinmux configuration).
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This depends on both the UART hardware and the board wiring.
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Note that this property is mutually-exclusive with "cts-gpios" and
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"rts-gpios" above.
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Examples:
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uart1: serial@48022000 {
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compatible = "ti,am3352-uart", "ti,omap3-uart";
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ti,hwmods = "uart2";
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clock-frequency = <48000000>;
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reg = <0x48022000 0x2000>;
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interrupts = <73>;
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dmas = <&edma 28 0>, <&edma 29 0>;
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dma-names = "tx", "rx";
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dtr-gpios = <&gpio2 22 GPIO_ACTIVE_LOW>;
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dsr-gpios = <&gpio2 23 GPIO_ACTIVE_LOW>;
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dcd-gpios = <&gpio2 24 GPIO_ACTIVE_LOW>;
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rng-gpios = <&gpio2 25 GPIO_ACTIVE_LOW>;
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cts-gpios = <&gpio0 12 GPIO_ACTIVE_LOW>;
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rts-gpios = <&gpio0 13 GPIO_ACTIVE_LOW>;
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status = "okay";
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};
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scifa4: serial@e6c80000 {
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compatible = "renesas,scifa-sh73a0", "renesas,scifa";
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reg = <0xe6c80000 0x100>;
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interrupts = <GIC_SPI 78 IRQ_TYPE_LEVEL_HIGH>;
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clocks = <&mstp2_clks SH73A0_CLK_SCIFA4>;
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clock-names = "fck";
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power-domains = <&pd_a3sp>;
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uart-has-rtscts;
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status = "okay";
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};
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