Re: [PATCH] net, can, ti_hecc: add DT support for the ti,hecc controller

On 10/20/2015 04:57 PM, Anton.Glukhov wrote:

Hello Marc, Heiko!
I'm sorry for the delay!

On 19.10.2015 10:31, Marc Kleine-Budde wrote:

quoted

On 10/19/2015 09:27 AM, Heiko Schocher wrote:

quoted

quoted

quoted

  .../devicetree/bindings/net/can/ti_hecc-can.txt    | 20 ++++++++++
  arch/arm/boot/dts/am3517.dtsi                      | 13 +++++++
  drivers/net/can/ti_hecc.c                          | 45 +++++++++++++++++++++-
  3 files changed, 76 insertions(+), 2 deletions(-)
  create mode 100644 Documentation/devicetree/bindings/net/can/ti_hecc-can.txt

diff --git a/Documentation/devicetree/bindings/net/can/ti_hecc-can.txt b/Documentation/devicetree/bindings/net/can/ti_hecc-can.txt
new file mode 100644
index 0000000..09fab59
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/can/ti_hecc-can.txt

@@ -0,0 +1,20 @@
+* TI HECC CAN *
+
+Required properties:
+  - compatible: Should be "ti,hecc"

We usually put the name of the first SoC this IP core appears in to the
compatible.

Ok, so "ti,am335xx-hecc" would be OK?
@Anton: you used "am35x" ... it should be "am35xx"

The "xx" is not okay. Give precisely the first SoC Version this IP core
was implemented in.

It's OMAP3 based arch, but HECC is implemented only in AM3505 and AM3517 SoCs.
So, I'm confused about what's "name" should I use.

Which SoC was available first? Pick that.

quoted

quoted

quoted

quoted

+  - reg: Should contain CAN controller registers location and length
+  - interrupts: Should contain IRQ line for the CAN controller

I'm missing the description of the ti,* properties. I think they are
required, too. Although the code doesn't enforce it.

Ok.

quoted

quoted

+
+Example:
+
+	can0: hecc@5c050000 {
+		compatible = "ti,hecc";
+		reg = <0x5c050000 0x4000>;
+		interrupts = <24>;
+		ti,hecc_scc_offset = <0>;
+		ti,hecc_scc_ram_offset = <0x3000>;
+		ti,hecc_ram_offset = <0x3000>;
+		ti,hecc_mbx_offset = <0x2000>;
+		ti,hecc_int_line = <0>;
+		ti,hecc_version = <1>;

Versioning in the OF world is done via the compatible. Are the offsets a
per SoC parameter? I'm not sure if it's better to put
the offsets into the driver.

I am unsure here too..

The devicetree people will hopefully help here.

I added offsets here just make it consistent with platform data in machine file.
Actually it seems that it's not necessary to put offsets in DT file and I can move it to driver.
But again, it was added to keep consistency.

The DT is supposed to be OS independent, copying from platform data to
DT is sometimes not the best way to go. Make yourself heard on the
devicetree mailinglist and figure out what's the best way to go here.

Are the offsets for the AM3505 and AM3517 identical?

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |