Re: [PATCH 2/2] irqchip/renesas-intc-irqpin: Add R-Car Gen1 fallback binding

On Mon, Dec 12, 2016 at 12:43:11PM -0600, Rob Herring wrote:

On Fri, Dec 09, 2016 at 01:52:20PM +0100, Geert Uytterhoeven wrote:

quoted

Hi Simon,

On Fri, Dec 9, 2016 at 11:50 AM, Simon Horman
[off-list ref] wrote:

quoted

In the case of Renesas R-Car hardware we know that there are generations of
SoCs, e.g. Gen 1, Gen 2 and Gen 3. But beyond that its not clear what the

it's

quoted

relationship between IP blocks might be. For example, I believe that
r8a7779 is older than r8a7778 but that doesn't imply that the latter is a
descendant of the former or vice versa.

We can, however, by examining the documentation and behaviour of the
hardware at run-time observe that the current driver implementation appears
to be compatible with the IP blocks on SoCs within a given generation.

For the above reasons and convenience when enabling new SoCs a
per-generation fallback compatibility string scheme being adopted for
drivers for Renesas SoCs.

Signed-off-by: Simon Horman <horms+renesas-/R6kz+dDXgpPR4JQBCEnsQ@public.gmane.org>
---
 .../interrupt-controller/renesas,intc-irqpin.txt   | 44 ++++++++++++----------
 drivers/irqchip/irq-renesas-intc-irqpin.c          |  2 +
 2 files changed, 26 insertions(+), 20 deletions(-)

diff --git a/Documentation/devicetree/bindings/interrupt-controller/renesas,intc-irqpin.txt b/Documentation/devicetree/bindings/interrupt-controller/renesas,intc-irqpin.txt
index 772c550d3b4b..e5a5251be9f5 100644
--- a/Documentation/devicetree/bindings/interrupt-controller/renesas,intc-irqpin.txt
+++ b/Documentation/devicetree/bindings/interrupt-controller/renesas,intc-irqpin.txt

@@ -2,13 +2,19 @@ DT bindings for the R-/SH-Mobile irqpin controller

 Required properties:

-- compatible: has to be "renesas,intc-irqpin-<soctype>", "renesas,intc-irqpin"
-  as fallback.
-  Examples with soctypes are:
+- compatible:
     - "renesas,intc-irqpin-r8a7740" (R-Mobile A1)
     - "renesas,intc-irqpin-r8a7778" (R-Car M1A)
     - "renesas,intc-irqpin-r8a7779" (R-Car H1)
     - "renesas,intc-irqpin-sh73a0" (SH-Mobile AG5)
+    - "renesas,rcar-gen1-intc-irqpin" (generic R-Car Gen1 compatible device)

Does it make sense to add a new family-specific compatible value to a driver
that's unlikely to receive more users in the future? More recent SoCs use
renesas,irqc.

If that's the case, then no. Please don't go crazy with your generic 
strings. I don't mind them, but I don't know that I'd call it best 
practice.

Understood. I do not see any new users of this driver on the horizon
and given the above I withdraw this patch.
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html