Re: [PATCH v5 2/5] dt-bindings: net: wireless: brcm4329-fmac: add clock description for AP6275P
From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2024-07-30 10:18:17
Also in:
linux-arm-kernel, linux-devicetree, linux-rockchip, linux-wireless, lkml
On 30/07/2024 11:52, Arend Van Spriel wrote:
On July 30, 2024 11:01:43 AM Krzysztof Kozlowski [off-list ref] wrote: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?
Yes, it is handled correctly. That's a basic use-case, handled by CCF since some years (~12?). Anyway, whatever OS is doing (or not doing) with the clocks is independent of the bindings here. The question is about hardware - does this node, which represents PCI interface of the chip, has/uses the clocks? Best regards, Krzysztof