Re: [PATCH v1] spi: dt-bindings: spi-rockchip: restrict num-cs

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On 1/23/24 11:49, Johan Jonker wrote:


On 1/23/24 10:17, Luis de Arquer wrote:
On 1/22/24 23:59, Johan Jonker wrote:
In the driver spi-rockchip.c max_native_cs is limited to 4 and the
default num-cs property is 1. Restrict num-cs in spi-rockchip.yaml.



Doesn't num-cs include gpio chip selects too?
I have a setup with num-cs = <12> which uses non-native cs-gpios just fine

Given that bindings and Linux drivers capabilities are 2 separate things.
However this document has also a purpose that must notify mainline maintainers if users submit bogus DT values.
Currently that limit is set to 4 in the mainline driver.
You are free to submit a real board file/patch serie afterwords as proof for review with 12 spi chips and then adjust this limit and increase ROCKCHIP_SPI_MAX_CS_NUM.

Hi Johan,

OK to that, I was not aware a driver could limit num-cs (I thought it could be extended with as many gpios as needed without involving the controller driver). I thought of num-cs as a spi subsystem generic thing.

In fact, I was reviewing the setup I mentioned, and even it defines 12 cs in the controller with no driver complaints, so far only 3 of them are mapped to devices (I'll have to review the driver before going any futher!)

Luis



Johan


Luis

Signed-off-by: Johan Jonker <jbx6244@xxxxxxxxx>
---
   Documentation/devicetree/bindings/spi/spi-rockchip.yaml | 5 +++++
   1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/spi/spi-rockchip.yaml b/Documentation/devicetree/bindings/spi/spi-rockchip.yaml
index e4941e9212d1..00d555bcbad3 100644
--- a/Documentation/devicetree/bindings/spi/spi-rockchip.yaml
+++ b/Documentation/devicetree/bindings/spi/spi-rockchip.yaml
@@ -65,6 +65,11 @@ properties:
         - const: tx
         - const: rx

+  num-cs:
+    default: 1
+    minimum: 1
+    maximum: 4
+
     rx-sample-delay-ns:
       default: 0
       description:
--
2.39.2


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