Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

* 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

	};

* 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;

	};

* 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>;

	};

   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:

	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. */

	}

5. REFERENCES

 [1]	include/linux/serial.h

 [2]	Documentation/devicetree/bindings/serial/rs485.txt

	select ARCH_REQUIRE_GPIOLIB

	select SAMSUNG_CLKSRC

	select SAMSUNG_IRQ_VIC_TIMER

	select SAMSUNG_IRQ_UART

	select S3C_GPIO_TRACK

	select S3C_GPIO_PULL_UPDOWN

	select S3C_GPIO_CFG_S3C24XX