Thread (9 messages) 9 messages, 5 authors, 2013-11-03

Re: [PATCH 5/5] serial: sh-sci: Add device tree bindings documentation

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: 2013-11-03 17:09:58
Also in: linux-serial, linux-sh

Hi Kumar,

On Thursday 31 October 2013 10:00:36 Kumar Gala wrote:
On Oct 31, 2013, at 9:55 AM, Laurent Pinchart wrote:
quoted
On Thursday 31 October 2013 09:42:48 Kumar Gala wrote:
quoted
On Oct 29, 2013, at 5:29 AM, Laurent Pinchart wrote:
quoted
Document the device tree bindings for the sci serial port devices.

Cc: devicetree@vger.kernel.org
Signed-off-by: Laurent Pinchart
[off-list ref]
---
.../bindings/serial/renesas,sci-serial.txt         | 51 ++++++++++++++++
1 file changed, 51 insertions(+)
create mode 100644
Documentation/devicetree/bindings/serial/renesas,sci-serial.txt

diff --git
a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt new
file mode 100644
index 0000000..5658b4f
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
@@ -0,0 +1,51 @@
+* Renesas SH-Mobile Serial Communication Interface
+
+Required properties:
+
+  - compatible: should be one of the following.
Being pedantic, but how about saying 'one of the following types (scif,
scifa, scifb, or hscif)
Sounds good to me.
quoted
quoted
+
+    - "renesas,scif-r8a7790" for R8A7790 (R-Car H2) SCIF compatible
UART.
+    - "renesas,scifa-r8a7790" for R8A7790 (R-Car H2) SCIFA compatible
UART.
+    - "renesas,scifb-r8a7790" for R8A7790 (R-Car H2) SCIFB compatible
UART.
+    - "renesas,hscif-r8a7790" for R8A7790 (R-Car H2) HSCIF compatible
UART.
+    - "renesas,scif-generic" for generic SCIF compatible UART.
+    - "renesas,scifa-generic" for generic SCIFA compatible UART.
+    - "renesas,scifb-generic" for generic SCIFB compatible UART.
+    - "renesas,hscif-generic" for generic HSCIF compatible UART.
+
+    When compatible with the generic version, nodes must also list the
+    SoC-specific version corresponding to the platform.
+
+  - reg: Base address and length of the memory resource used by the
UART.
+
+  - interrupt-parent: Reference to the parent interrupt controller.
+  - interrupts: Interrupt number(s). Depending on the SoC SCIx UARTs
are
tied
+    to one or multiple interrupt lines. When using multiple interrupt
lines,
+    specify the interrupt names as described below.
+
+  - clocks: Reference to the SCIx UART interface clock.
+  - clock-names: Should be "sci_ick".
+
+Optional properties:
+
+  - interrupt-names: When using multiple interrupts, report the
interrupt
+    names as "eri" (receive error), "rxi" (receive), "txi" (transmit)
and
+    "bri" (break). When using a single interrupt this property should
not
be +    present.
Hmm, is there a reason not to just have the 4 interrupts always present
and in the case they are all wired to the same interrupt, just have the
interrupts all be the same?

example:

interrupts = <0 144 4>, <0 144 4>, <0 144 4>, <0 144 4>;
The multiple interrupts case is the exception, I thought it would be
easier to specify a single interrupt in the general case and have a more
complex binding for the exceptions.
quoted
quoted
+
+Note: Each enabled SCIx UART should have an alias correctly numbered in
the +"aliases" node.
+
+Example:
+	aliases {
+		serial0 = &scifa0;
+	};
+
+	scifa0: serial@e6c40000 {
+		compatible = "renesas,scifa-r8a7790", "renesas,scifa-generic";
+		reg = <0 0xe6c40000 0 64>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 144 4>;
+		clocks = <&mstp2_clks 4>;
+		clock-names = "sci_ick";
+	};
might be nice to have an example with the 4 interrupts.
The example would be pretty theoretical, as the r8a7790 uses a single
interrupt in all cases. What about adding such an example when adding an
SoC that uses multiple interrupts to the DT bindings documentation ?
I'm fine with that if we strip the multiple interrupt bits out of the
binding until a device/compatible exists that needs it.
I'll do that and repost.

-- 
Regards,

Laurent Pinchart
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