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From: Chen-Yu Tsai <wenst@chromium.org>
Date: Tue, 9 Jan 2024 18:26:48 +0800
Message-ID: <CAGXv+5EHc08sv5+=tnFmoDAQhbD7ZS+XBOyaiSndaiSFhMksAA@mail.gmail.com>
Subject: Re: [RFC 8/9] PCI/pwrseq: add a pwrseq driver for QCA6390
To: Arnd Bergmann <arnd@arndb.de>
Cc: Kalle Valo <kvalo@kernel.org>, Jeff Johnson <quic_jjohnson@quicinc.com>, 
	Bartosz Golaszewski <brgl@bgdev.pl>, "David S . Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, 
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>, Rob Herring <robh+dt@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	Bjorn Andersson <andersson@kernel.org>, Konrad Dybcio <konrad.dybcio@linaro.org>, 
	Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, 
	Bjorn Helgaas <bhelgaas@google.com>, =?UTF-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>, 
	Jernej Skrabec <jernej.skrabec@gmail.com>, Chris Morgan <macromorgan@hotmail.com>, 
	Linus Walleij <linus.walleij@linaro.org>, Geert Uytterhoeven <geert+renesas@glider.be>, 
	Neil Armstrong <neil.armstrong@linaro.org>, 
	=?UTF-8?B?TsOtY29sYXMgRi4gUi4gQS4gUHJhZG8=?= <nfraprado@collabora.com>, 
	Marek Szyprowski <m.szyprowski@samsung.com>, Peng Fan <peng.fan@nxp.com>, 
	Robert Richter <rrichter@amd.com>, Dan Williams <dan.j.williams@intel.com>, 
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	=?UTF-8?Q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>, 
	Huacai Chen <chenhuacai@kernel.org>, Alex Elder <elder@linaro.org>, 
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>, 
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>, linux-wireless@vger.kernel.org, 
	Netdev <netdev@vger.kernel.org>, devicetree@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, 
	linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
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On Tue, Jan 9, 2024 at 6:15=E2=80=AFPM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Tue, Jan 9, 2024, at 11:09, Kalle Valo wrote:
> > Chen-Yu Tsai <wenst@chromium.org> writes:
> >> On Tue, Jan 9, 2024 at 5:18=E2=80=AFPM Kalle Valo <kvalo@kernel.org> w=
rote:
> >>> Jeff Johnson <quic_jjohnson@quicinc.com> writes:
> >>>
> >>> > On 1/4/2024 5:01 AM, Bartosz Golaszewski wrote:
> >>> >> diff --git a/drivers/pci/pcie/pwrseq/Kconfig b/drivers/pci/pcie/pw=
rseq/Kconfig
> >>> >> index 010e31f432c9..f9fe555b8506 100644
> >>> >> --- a/drivers/pci/pcie/pwrseq/Kconfig
> >>> >> +++ b/drivers/pci/pcie/pwrseq/Kconfig
> >>> >> @@ -6,3 +6,14 @@ menuconfig PCIE_PWRSEQ
> >>> >>      help
> >>> >>        Say yes here to enable support for PCIe power sequencing
> >>> >>        drivers.
> >>> >> +
> >>> >> +if PCIE_PWRSEQ
> >>> >> +
> >>> >> +config PCIE_PWRSEQ_QCA6390
> >>> >> +    tristate "PCIe Power Sequencing driver for QCA6390"
> >>> >> +    depends on ARCH_QCOM || COMPILE_TEST
> >>> >> +    help
> >>> >> +      Enable support for the PCIe power sequencing driver for the
> >>> >> +      ath11k module of the QCA6390 WLAN/BT chip.
> >>> >> +
> >>> >> +endif
> >>> >
> >>> > As I mentioned in the 5/9 patch I'm concerned that the current
> >>> > definition of PCIE_PWRSEQ and PCIE_PWRSEQ_QCA6390 will effectively =
hide
> >>> > the fact that QCA6390 may need additional configuration since the m=
enu
> >>> > item will only show up if you have already enabled PCIE_PWRSEQ.
> >>> > Yes I see that these are set in the defconfig in 9/9 but I'm concer=
ned
> >>> > about the more generic case.
> >>> >
> >>> > I'm wondering if there should be a separate config QCA6390 within a=
th11k
> >>> > which would then select PCIE_PWRSEQ and PCIE_PWRSEQ_QCA6390
> >>>
> >>> Or is it possible to provide an optional dependency in Kconfig (I gue=
ss
> >>
> >> imply PCIE_PWRSEQ
> >> imply PCIE_PWRSEQ_QCA6390
> >> ?
> >
> > Nice, I had forgotten imply altogether. Would 'imply
> > PCIE_PWRSEQ_QCA6390' in ath11k Kconfig be enough to address Jeff's
> > concern?
>
> Please don't use imply (ever), it doesn't normally do
> what you want. In this case, the only effect the
> 'imply' has is to change the default of the PCIE_PWRSEQ_QCA6390
> option when a defconfig contains QCA6390.
>
> If this is indeed what you want, it's still better to do the
> equivalent expression in PCIE_PWRSEQ_QCA6390 rather than ATH11K:
>
> config PCIE_PWRSEQ_QCA6390
>       tristate "PCIe Power Sequencing driver for QCA6390"
>       default ATH11K && ARCH_QCOM

PCIE_PWRSEQ_QCA6390 is also guarded by PCIE_PWRSEQ though. That would
require the default statement to be duplicated to the PCIE_PWRSEQ option
as well.

Presumably we'd get a few more power sequencing drivers, and the list of
default statements for PCIE_PWRSEQ would grow.

If that's acceptable then Arnd's proposal plus duplicating it to
PCIE_PWRSEQ should work as described.

ChenYu