On Wed, Sep 23, 2020 at 1:44 AM Ran Wang [off-list ref] wrote:

Hi Rob,

On Wednesday, September 23, 2020 10:33 AM, Rob Herring wrote:

quoted

On Wed, Sep 16, 2020 at 04:18:27PM +0800, Ran Wang wrote:

quoted

From: Biwen Li <redacted>

The 'fsl,ippdexpcr1-alt-addr' property is used to handle an errata
A-008646 on LS1021A

Signed-off-by: Biwen Li <redacted>
Signed-off-by: Ran Wang <redacted>
---
 Documentation/devicetree/bindings/soc/fsl/rcpm.txt | 19
+++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/Documentation/devicetree/bindings/soc/fsl/rcpm.txt

b/Documentation/devicetree/bindings/soc/fsl/rcpm.txt
index 5a33619..1be58a3 100644

--- a/Documentation/devicetree/bindings/soc/fsl/rcpm.txt
+++ b/Documentation/devicetree/bindings/soc/fsl/rcpm.txt

@@ -34,6 +34,11 @@ Chassis Version          Example Chips
 Optional properties:
  - little-endian : RCPM register block is Little Endian. Without it RCPM
    will be Big Endian (default case).
+ - fsl,ippdexpcr1-alt-addr : The property is related to a hardware issue
+   on SoC LS1021A and only needed on SoC LS1021A.
+   Must include 2 entries:
+   The first entry must be a link to the SCFG device node.
+   The 2nd entry must be offset of register IPPDEXPCR1 in SCFG.

You don't need a DT change for this. You can find SCFG node by its compatible
string and then the offset should be known given this issue is only on 1 SoC.

Did you mean that RCPM driver just to access IPPDEXPCR1 shadowed register in SCFG
directly without fetching it's offset info. from DT?

Yes. There's only 1 possible value of the offset because there's only
one SoC, so the driver can hardcode the offset. And I assume there's
only one SCFG node, so you can find it by its compatible string
(of_find_compatible_node).

Rob