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Message-ID: <20170724230521.1436-3-fcooper@ti.com>
Date: Mon, 24 Jul 2017 18:05:19 -0500
From: Franklin S Cooper Jr <fcooper@...com>
To: <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
<netdev@...r.kernel.org>, <linux-can@...r.kernel.org>,
<wg@...ndegger.com>, <mkl@...gutronix.de>, <robh+dt@...nel.org>,
<quentin.schulz@...e-electrons.com>,
<dev.kurt@...dijck-laurijssen.be>, <andrew@...n.ch>,
<sergei.shtylyov@...entembedded.com>, <socketcan@...tkopp.net>
CC: Franklin S Cooper Jr <fcooper@...com>
Subject: [PATCH v2 2/4] can: fixed-transceiver: Add documentation for CAN fixed transceiver bindings
Add documentation to describe usage of the new fixed transceiver binding.
This new binding is applicable for any CAN device therefore it exists as
its own document.
Signed-off-by: Franklin S Cooper Jr <fcooper@...com>
---
Version 2:
Tweak commit message working
Tweak wording for properties
Drop unit addressing
Give example if CAN-FD isn't supported
.../bindings/net/can/fixed-transceiver.txt | 42 ++++++++++++++++++++++
1 file changed, 42 insertions(+)
create mode 100644 Documentation/devicetree/bindings/net/can/fixed-transceiver.txt
diff --git a/Documentation/devicetree/bindings/net/can/fixed-transceiver.txt b/Documentation/devicetree/bindings/net/can/fixed-transceiver.txt
new file mode 100644
index 0000000..dc7e3eb
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/can/fixed-transceiver.txt
@@ -0,0 +1,42 @@
+Fixed transceiver Device Tree binding
+------------------------------
+
+CAN transceiver typically limits the max speed in standard CAN and CAN FD
+modes. Typically these limitations are static and the transceivers themselves
+provide no way to detect this limitation at runtime. For this situation,
+the "fixed-transceiver" node can be used.
+
+Properties:
+
+Optional:
+ max-arbitration-speed: a positive non 0 value that determines the max
+ speed that CAN can run in non CAN-FD mode or during the
+ arbitration phase in CAN-FD mode.
+
+ max-data-speed: a positive non 0 value that determines the max data rate
+ that can be used in CAN-FD mode. A value of -1 implies
+ CAN-FD is not supported by the transceiver.
+
+Examples:
+
+Based on Texas Instrument's TCAN1042HGV CAN Transceiver
+
+m_can0 {
+ ....
+ fixed-transceiver {
+ max-arbitration-speed = <1000000>;
+ max-data-speed = <5000000>;
+ };
+ ...
+};
+
+Based on a CAN Transceiver that doesn't support CAN-FD. Only needed if the
+CAN IP supports CAN-FD but is using a transceiver that doesn't.
+
+m_can0 {
+ ....
+ fixed-transceiver {
+ max-data-speed = <(-1)>;
+ };
+ ...
+};
--
2.10.0
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