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Diffstat (limited to 'Documentation')
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 0000000..1e753c6 --- /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 0000000..a49d9a1 --- /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 0000000..f13f1c5 --- /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 a493238..079cb3d 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 |