4 files changed, 91 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/serial/rs485.txt b/Documentation/devicetree/bindings/serial/rs485.txt
new file mode 100644
index 000000000000..1e753c69fc83
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/rs485.txt
@@ -0,0 +1,31 @@
+* 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
+        };
+
diff --git a/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt b/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt
new file mode 100644
index 000000000000..a49d9a1d4ccf
--- /dev/null
+++ b/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt
@@ -0,0 +1,27 @@
+* Atmel Universal Synchronous Asynchronous Receiver/Transmitter (USART)
+
+Required properties:
+- compatible: Should be "atmel,<chip>-usart"
+  The compatible <chip> indicated will be the first SoC to support an
+  additional mode or an USART new feature.
+- reg: Should contain registers location and length
+- interrupts: Should contain interrupt
+
+Optional properties:
+- atmel,use-dma-rx: use of PDC or DMA for receiving data
+- atmel,use-dma-tx: use of PDC or DMA for transmitting data
+
+<chip> compatible description:
+- at91rm9200:  legacy USART support
+- at91sam9260: generic USART implementation for SAM9 SoCs
+
+Example:
+
+        usart0: serial@fff8c000 {
+                compatible = "atmel,at91sam9260-usart";
+                reg = <0xfff8c000 0x4000>;
+                interrupts = <7>;
+                atmel,use-dma-rx;
+                atmel,use-dma-tx;
+        };
+
diff --git a/Documentation/devicetree/bindings/tty/serial/snps-dw-apb-uart.txt b/Documentation/devicetree/bindings/tty/serial/snps-dw-apb-uart.txt
new file mode 100644
index 000000000000..f13f1c5be91c
--- /dev/null
+++ b/Documentation/devicetree/bindings/tty/serial/snps-dw-apb-uart.txt
@@ -0,0 +1,25 @@
+* Synopsys DesignWare ABP UART
+
+Required properties:
+- compatible : "snps,dw-apb-uart"
+- reg : offset and length of the register set for the device.
+- interrupts : should contain uart interrupt.
+- clock-frequency : the input clock frequency for the UART.
+
+Optional properties:
+- reg-shift : quantity to shift the register offsets by.  If this property is
+  not present then the register offsets are not shifted.
+- reg-io-width : the size (in bytes) of the IO accesses that should be
+  performed on the device.  If this property is not present then single byte
+  accesses are used.
+
+Example:
+
+        uart@80230000 {
+                compatible = "snps,dw-apb-uart";
+                reg = <0x80230000 0x100>;
+                clock-frequency = <3686400>;
+                interrupts = <10>;
+                reg-shift = <2>;
+                reg-io-width = <4>;
+        };
diff --git a/Documentation/serial/serial-rs485.txt b/Documentation/serial/serial-rs485.txt
index a4932387bbfb..079cb3df62cf 100644
--- a/Documentation/serial/serial-rs485.txt
+++ b/Documentation/serial/serial-rs485.txt
@@ -28,6 +28,10 @@
    RS485 communications. This data structure is used to set and configure RS485
    parameters in the platform data and in ioctls.
 
+   The device tree can also provide RS485 boot time parameters (see [2]
+   for bindings). The driver is in charge of filling this data structure from
+   the values given by the device tree.
+
    Any driver for devices capable of working both as RS232 and RS485 should
    provide at least the following ioctls:
 
@@ -104,6 +108,9 @@
         rs485conf.flags |= SER_RS485_RTS_AFTER_SEND;
         rs485conf.delay_rts_after_send = ...;
 
+        /* Set this flag if you want to receive data even whilst sending data */
+        rs485conf.flags |= SER_RS485_RX_DURING_TX;
+
         if (ioctl (fd, TIOCSRS485, &rs485conf) < 0) {
                 /* Error handling. See errno. */
         }
@@ -118,3 +125,4 @@
 5. REFERENCES
 
  [1]    include/linux/serial.h
+ [2]    Documentation/devicetree/bindings/serial/rs485.txt