linux-kernel - Re: [PATCH v3 4/5] wifi: brcmfmac: Add optional lpo clock enable support

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Date: Sun, 30 Jun 2024 11:54:09 +0200
From: Stefan Wahren <wahrenst@....net>
To: wens@...nel.org, Jacobe Zang <jacobe.zang@...ion.com>
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 Nick Xie <nick@...das.com>
Subject: Re: [PATCH v3 4/5] wifi: brcmfmac: Add optional lpo clock enable
 support

Am 30.06.24 um 11:15 schrieb Chen-Yu Tsai:
> On Sun, Jun 30, 2024 at 5:10 PM Jacobe Zang <jacobe.zang@...ion.com> wrote:
>> Hi Stefan,
>>
>>>> WiFi modules often require 32kHz clock to function. Add support to
>>>> enable the clock to PCIe driver.
>>> the low power clock is independent from the host interface like PCIe. So
>>> the clock handling should move to the common code. Sorry, not i cannot
>>> give a good suggestion, what's the best place for this.
>> I think the clock is used by the PCIe device so enable it in this file. Also I checked
>> use of clock which in spi[0] or sdio[0] device was enabled similarly to this.
>>
>> [0] https://lore.kernel.org/all/20210806081229.721731-4-claudiu.beznea@microchip.com/
> You're looking at the wrong driver. For brcmfmac, the lpo clock is toggled
> by the MMC pwrseq code. And for the Bluetooth side (where it really matters)
> for UARTs, it is in drivers/bluetooth/hci_bcm.c. and documented in the
> binding Documentation/devicetree/bindings/net/broadcom-bluetooth.yaml
Thanks for clarifying. So this change handles the PCIe case without
bluetooth. For USB the clock control doesn't make sense.

Sorry for the noise
>
>
> ChenYu