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authorNicolas Ferre <nicolas.ferre@atmel.com>2011-10-12 18:06:56 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-10-18 16:40:33 -0700
commit0331bbf3c6fd9997e5f0d165840229ccfeba6548 (patch)
tree3aec3b01a2dc15dc39193034775a8b15d6487299 /Documentation/devicetree/bindings/serial
parent631180aca723cb92e128fdac5fd144e913ca84e5 (diff)
tty/serial: RS485 bindings for device tree
Generic bindings for RS485 feature included in some UARTs. Those bindings have to be used withing an UART device tree node. Documentation updated to link to the bindings definition. Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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+* RS485 serial communications
+
+The RTS signal is capable of automatically controlling line direction for
+the built-in half-duplex mode.
+The properties described hereafter shall be given to a half-duplex capable
+UART node.
+
+Required properties:
+- rs485-rts-delay: prop-encoded-array <a b> where:
+ * a is the delay beteween rts signal and beginning of data sent in milliseconds.
+ it corresponds to the delay before sending data.
+ * b is the delay between end of data sent and rts signal in milliseconds
+ it corresponds to the delay after sending data and actual release of the line.
+
+Optional properties:
+- linux,rs485-enabled-at-boot-time: empty property telling to enable the rs485
+ feature at boot time. It can be disabled later with proper ioctl.
+- rs485-rx-during-tx: empty property that enables the receiving of data even
+ whilst sending data.
+
+RS485 example for Atmel USART:
+ usart0: serial@fff8c000 {
+ compatible = "atmel,at91sam9260-usart";
+ reg = <0xfff8c000 0x4000>;
+ interrupts = <7>;
+ atmel,use-dma-rx;
+ atmel,use-dma-tx;
+ linux,rs485-enabled-at-boot-time;
+ rs485-rts-delay = <0 200>; // in milliseconds
+ };
+