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Message-ID: <6fe7914a2c39245ac9a05cdb9962b88c409ec1a4.1433253787.git.cyrille.pitchen@atmel.com>
Date: Tue, 2 Jun 2015 16:18:21 +0200
From: Cyrille Pitchen <cyrille.pitchen@...el.com>
To: <nicolas.ferre@...el.com>, <gregkh@...uxfoundation.org>,
<wenyou.yang@...el.com>, <ludovic.desroches@...el.com>,
<leilei.zhao@...el.com>, <josh.wu@...el.com>,
<alexandre.belloni@...e-electrons.com>,
<linux-serial@...r.kernel.org>
CC: <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<devicetree@...r.kernel.org>, <galak@...eaurora.org>,
<ijc+devicetree@...lion.org.uk>, <mark.rutland@....com>,
<pawel.moll@....com>, <robh+dt@...nel.org>,
Cyrille Pitchen <cyrille.pitchen@...el.com>
Subject: [PATCH linux-next 1/4] ARM: at91/dt: add new DT properties for Atmel usart
add 3 new properties:
- "atmel,fifo-size": to enable FIFO support
- "atmel,rts-low-threshold" and "atmel,rts-high-threshold": to control
the hardware handshake flow control.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@...el.com>
---
Documentation/devicetree/bindings/serial/atmel-usart.txt | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/Documentation/devicetree/bindings/serial/atmel-usart.txt b/Documentation/devicetree/bindings/serial/atmel-usart.txt
index 90787aa..6158418 100644
--- a/Documentation/devicetree/bindings/serial/atmel-usart.txt
+++ b/Documentation/devicetree/bindings/serial/atmel-usart.txt
@@ -22,6 +22,21 @@ Optional properties:
memory peripheral interface and USART DMA channel ID, FIFO configuration.
Refer to dma.txt and atmel-dma.txt for details.
- dma-names: "rx" for RX channel, "tx" for TX channel.
+- atmel,fifo-size: size of the TX and RX FIFOs. That is to say the maximum
+ number of data each FIFO can store. A positive size enables FIFO support.
+ A zero size or a missing property disables FIFO support.
+- atmel,rts-low-threshold: when the RX FIFO level, ie the number of data
+ available to be read from the RX FIFO, crosses down this threshold the RTS
+ line is driven to low level to tell the remote peer that it can (re)start
+ sending new data.
+- atmel,rts-high-threshold: when the RX FIFO level crosses up this threshold,
+ the RTS line is driven to high level to tell the remote peer that it should
+ stop sending new data.
+
+0 < rts-low-threshold < rts-high-threshold <= fifo-size
+
+These two thresholds are only used when both the FIFO support and the hardware
+handshake mode are enabled.
<chip> compatible description:
- at91rm9200: legacy USART support
--
1.8.2.2
--
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