Thread (25 messages) 25 messages, 5 authors, 2024-07-31

Re: [PATCH v5 2/5] dt-bindings: net: wireless: brcm4329-fmac: add clock description for AP6275P

From: Jacobe Zang <hidden>
Date: 2024-07-30 10:00:25
Also in: linux-arm-kernel, linux-devicetree, linux-rockchip, linux-wireless, lkml

quoted
On 30/07/2024 08:37, Arend Van Spriel wrote:
quoted
+ Linus W

On July 30, 2024 5:31:15 AM Jacobe Zang [off-list ref] wrote:
quoted
Not only AP6275P Wi-Fi device but also all Broadcom wireless devices allow
external low power clock input. In DTS the clock as an optional choice in
the absence of an internal clock.

Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Jacobe Zang <redacted>
---
.../bindings/net/wireless/brcm,bcm4329-fmac.yaml          | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git
a/Documentation/devicetree/bindings/net/wireless/brcm,bcm4329-fmac.yaml
b/Documentation/devicetree/bindings/net/wireless/brcm,bcm4329-fmac.yaml
index 2c2093c77ec9a..a3607d55ef367 100644
--- a/Documentation/devicetree/bindings/net/wireless/brcm,bcm4329-fmac.yaml
+++ b/Documentation/devicetree/bindings/net/wireless/brcm,bcm4329-fmac.yaml
@@ -122,6 +122,14 @@ properties:
NVRAM. This would normally be filled in by the bootloader from platform
configuration data.

+  clocks:
+    items:
+      - description: External Low Power Clock input (32.768KHz)
+
+  clock-names:
+    items:
+      - const: lpo
+
We still have an issue that this clock input is also present in the
bindings specification broadcom-bluetooth.yaml (not in bluetooth
subfolder). This clock is actually a chip resource. What happens if both
are defined and both wifi and bt drivers try to enable this clock? Can this
be expressed in yaml or can we only put a textual warning in the property
descriptions?
Just like all clocks, what would happen? It will be enabled.
Oh, wow! Cool stuff. But seriously is it not a problem to have two entities
controlling one and the same clock? Is this use-case taken into account by
the clock framework?
I have enabled the same clock both in bluetooth and wifi just now, they worked
well. Maybe this make sense?

---
Best Regards
Jacobe
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