linux/Documentation/devicetree/bindings/serial/fsl-mxs-auart.txt
Janusz Uzycki 7c573d7ea6 serial: mxs-auart: use mctrl_gpio helpers for handling modem signals
Dedicated CTS and RTS pins are unusable together with a lot of other
peripherals because they share the same line. Pinctrl is limited.

Moreover, the AUART controller doesn't handle DTR/DSR/DCD/RI signals,
so we have to control them via GPIO.

This patch permits to use GPIOs to control the CTS/RTS/DTR/DSR/DCD/RI
signals.

Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl>
Reviewed-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-06 14:57:18 -08:00

46 lines
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* Freescale MXS Application UART (AUART)
Required properties:
- compatible : Should be "fsl,<soc>-auart". The supported SoCs include
imx23 and imx28.
- reg : Address and length of the register set for the device
- interrupts : Should contain the auart interrupt numbers
- dmas: DMA specifier, consisting of a phandle to DMA controller node
and AUART DMA channel ID.
Refer to dma.txt and fsl-mxs-dma.txt for details.
- dma-names: "rx" for RX channel, "tx" for TX channel.
Optional properties:
- fsl,uart-has-rtscts : Indicate the UART has RTS and CTS lines
for hardware flow control,
it also means you enable the DMA support for this UART.
- {rts,cts,dtr,dsr,rng,dcd}-gpios: specify a GPIO for RTS/CTS/DTR/DSR/RI/DCD
line respectively. It will use specified PIO instead of the peripheral
function pin for the USART feature.
If unsure, don't specify this property.
Example:
auart0: serial@8006a000 {
compatible = "fsl,imx28-auart", "fsl,imx23-auart";
reg = <0x8006a000 0x2000>;
interrupts = <112>;
dmas = <&dma_apbx 8>, <&dma_apbx 9>;
dma-names = "rx", "tx";
cts-gpios = <&gpio1 15 GPIO_ACTIVE_LOW>;
dsr-gpios = <&gpio1 16 GPIO_ACTIVE_LOW>;
dcd-gpios = <&gpio1 17 GPIO_ACTIVE_LOW>;
};
Note: Each auart port should have an alias correctly numbered in "aliases"
node.
Example:
aliases {
serial0 = &auart0;
serial1 = &auart1;
serial2 = &auart2;
serial3 = &auart3;
serial4 = &auart4;
};