From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leif Lindholm Subject: [PATCH v3 1/3] devicetree: of: Add bindings for chosen node, stdout-path Date: Thu, 27 Nov 2014 17:56:05 +0000 Message-ID: <1417110967-16284-2-git-send-email-leif.lindholm@linaro.org> References: <1417110967-16284-1-git-send-email-leif.lindholm@linaro.org> Return-path: In-Reply-To: <1417110967-16284-1-git-send-email-leif.lindholm@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: mark.rutland@arm.com, grant.likely@linaro.org, robh+dt@kernel.org, plagnioj@jcrosoft.com, ijc@debian.org, andrew@lunn.ch, s.hauer@pengutronix.de List-Id: devicetree@vger.kernel.org Add a global binding for the chosen node. Include a description of the stdout-path, and an explicit statement on its extra options in the context of a UART console. Opening description stolen from www.devicetree.org, and part of the remaining text provided by Mark Rutland. Signed-off-by: Leif Lindholm --- Documentation/devicetree/bindings/chosen.txt | 42 ++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 Documentation/devicetree/bindings/chosen.txt diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt new file mode 100644 index 0000000..9cd74e9 --- /dev/null +++ b/Documentation/devicetree/bindings/chosen.txt @@ -0,0 +1,42 @@ +The chosen node +--------------- + +The chosen node does not represent a real device, but serves as a place +for passing data between firmware and the operating system, like boot +arguments. Data in the chosen node does not represent the hardware. + + +stdout-path property +-------------------- + +Device trees may specify the device to be used for boot console output +with a stdout-path property under /chosen, as described in ePAPR, e.g. + +/ { + chosen { + stdout-path = "/serial@f00:115200"; + }; + + serial@f00 { + compatible = "vendor,some-uart"; + reg = <0xf00 0x10>; + }; +}; + +If the character ":" is present in the value, this terminates the path. +The meaning of any characters following the ":" is device-specific, and +must be specified in the relevant binding documentation. + +For UART devices, the format supported by uart_parse_options() is the +expected one. In this case, the format of the string is: + + {{{}}} + +where + + baud - baud rate in decimal + parity - 'n' (none), 'o', (odd) or 'e' (even) + bits - number of data bits + flow - 'r' (rts) + +For example: 115200n8r -- 1.7.10.4