On Fri, Jul 11, 2014 at 02:54:00PM +0200, Marc Kleine-Budde wrote:

On 07/11/2014 12:29 PM, Dong Aisheng wrote:

quoted

add M_CAN device tree binding documentation

Cc: Wolfgang Grandegger <redacted>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Varka Bhadram <redacted>
Signed-off-by: Dong Aisheng <redacted>
---
 .../devicetree/bindings/net/can/m_can.txt          |   65 ++++++++++++++++++++
 1 files changed, 65 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/net/can/m_can.txt

diff --git a/Documentation/devicetree/bindings/net/can/m_can.txt b/Documentation/devicetree/bindings/net/can/m_can.txt
new file mode 100644
index 0000000..c4cb263
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/can/m_can.txt

@@ -0,0 +1,65 @@
+Bosch MCAN controller Device Tree Bindings
+-------------------------------------------------
+
+Required properties:
+- compatible		: Should be "bosch,m_can" for M_CAN controllers
+- reg			: physical base address and size of the M_CAN
+			  registers map and Message RAM
+- reg-names		: Should be "m_can" and "message_ram"
+- interrupts		: Should be the interrupt number of M_CAN interrupt
+			  line 0 and line 1, could be same if sharing
+			  the same interrupt.
+- interrupt-names	: Should contain "int0" and "int1"
+- clocks		: Clocks used by controller, should be host clock
+			  and CAN clock.
+- clock-names		: Should contain "hclk" and "cclk"
+- pinctrl-<n>		: Pinctrl states as described in bindings/pinctrl/pinctrl-bindings.txt
+- pinctrl-names		: Names corresponding to the numbered pinctrl states
+- mram-cfg		: Message RAM configuration data.
+  Multiple M_CAN instances can share the same Message RAM and each element(e.g
+  Rx FIFO or Tx Buffer and etc) number in Message RAM is also configurable,
+  so this property is telling driver how the shared or private Message RAM
+  are used by this M_CAN controller.

Will you have to modify the binding, espeically the mram-cfg, if you add
canfd support to the driver?

No need, CANFD in i.MX6SX is using the same IP of Bosch M_CAN.

I think mram-cfg should have a vendor prefix, e.g.: bosch,mram-cfg

It's a good idea.
Will update it.

quoted

+
+  The format should be as follows:
+  <offset sidf_elems xidf_elems rxf0_elems rxf1_elems rxb_elems
+   txe_elems txb_elems>
+  The 'offset' is an address offset of the Message RAM where the following
+  elements start from. This is usually set to 0x0 if you're using a private
+  Message RAM. The remain cells are used to specify how many elements are used
+  for each FIFO/Buffer.
+
+M_CAN includes the following elements according to user manual:
+11-bit Filter	0-128 elements / 0-128 words
+29-bit Filter	0-64 elements / 0-128 words
+Rx FIFO 0	0-64 elements / 0-1152 words
+Rx FIFO 1	0-64 elements / 0-1152 words
+Rx Buffers	0-64 elements / 0-1152 words
+Tx Event FIFO	0-32 elements / 0-64 words
+Tx Buffers	0-32 elements / 0-576 words
+
+Please refer to 2.4.1 Message RAM Configuration in Bosch M_CAN user manual
+for details.
+
+Example:
+SoC dtsi:
+m_can1: can@020e8000 {
+	compatible = "bosch,m_can";
+	reg = <0x020e8000 0x4000>, <0x02298000 0x4000>;
+	reg-names = "m_can", "message_ram";
+	interrupts = <0 114 0x04>,
+		     <0 114 0x04>;
+	interrupt-names = "int0", "int1";
+	clocks = <&clks IMX6SX_CLK_CANFD>,
+		 <&clks IMX6SX_CLK_CANFD>;
+	clock-names = "hclk", "cclk";
+	mram-cfg = <0x0 0 0 32 0 0 0 1>;
+	status = "disabled";
+};
+
+Board dtsi:
+&m_can1 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_m_can1>;
+	status = "enabled";
+};

Marc
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Regards
Dong Aisheng