linux-kernel - Re: [PATCH v8 16/17] PCI/pwrctl: add a PCI power control driver for power sequenced devices

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Message-ID: <CAA8EJpomPLQmQbW8w3_ms_NMKHoSPcqBa7f2OhNTTOUSdB+9Eg@mail.gmail.com>
Date: Wed, 5 Jun 2024 02:34:52 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Bjorn Helgaas <helgaas@...nel.org>
Cc: Bartosz Golaszewski <brgl@...ev.pl>, Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>, 
	Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Marcel Holtmann <marcel@...tmann.org>, Luiz Augusto von Dentz <luiz.dentz@...il.com>, 
	"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	Balakrishna Godavarthi <quic_bgodavar@...cinc.com>, Rocky Liao <quic_rjliao@...cinc.com>, 
	Kalle Valo <kvalo@...nel.org>, Jeff Johnson <jjohnson@...nel.org>, 
	Bjorn Andersson <andersson@...nel.org>, Konrad Dybcio <konrad.dybcio@...aro.org>, 
	Bjorn Helgaas <bhelgaas@...gle.com>, Srini Kandagatla <srinivas.kandagatla@...aro.org>, 
	Elliot Berman <quic_eberman@...cinc.com>, Caleb Connolly <caleb.connolly@...aro.org>, 
	Neil Armstrong <neil.armstrong@...aro.org>, Alex Elder <elder@...nel.org>, 
	linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-bluetooth@...r.kernel.org, 
	netdev@...r.kernel.org, linux-wireless@...r.kernel.org, 
	ath11k@...ts.infradead.org, Jeff Johnson <quic_jjohnson@...cinc.com>, 
	ath12k@...ts.infradead.org, linux-pm@...r.kernel.org, 
	linux-pci@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>, kernel@...cinc.com, 
	Amit Pundir <amit.pundir@...aro.org>
Subject: Re: [PATCH v8 16/17] PCI/pwrctl: add a PCI power control driver for
 power sequenced devices

On Wed, 5 Jun 2024 at 02:23, Bjorn Helgaas <helgaas@...nel.org> wrote:
>
> On Tue, May 28, 2024 at 09:03:24PM +0200, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> >
> > Add a PCI power control driver that's capable of correctly powering up
> > devices using the power sequencing subsystem. The first users of this
> > driver are the ath11k module on QCA6390 and ath12k on WCN7850.
>
> Can you add a little detail here about what benefit we will see from
> this driver?  E.g., something that doesn't work correctly now, but
> will work with this driver?
>
> > +static const struct of_device_id pci_pwrctl_pwrseq_of_match[] = {
> > +     {
> > +             /* ATH11K in QCA6390 package. */
> > +             .compatible = "pci17cb,1101",
> > +             .data = "wlan",
> > +     },
> > +     {
> > +             /* ATH12K in WCN7850 package. */
> > +             .compatible = "pci17cb,1107",
> > +             .data = "wlan",
> > +     },
>
> IIUC, "pci17cb,1101" and "pci17cb,1107" exist partly so we can check
> that a DTS conforms to the schema, e.g., a "pci17cb,1101" node
> contains all the required regulators.  For that use, we obviously need
> a very specific "compatible" string.
>
> Is there any opportunity to add a more generic "compatible" string in
> addition to those so this list doesn't have to be updated for every
> PMU?  The .data here is "wlan" in both cases, and for this purpose, we
> don't care whether it's "pci17cb,1101" or "pci17cb,1107".

These two devices have different set of regulators and different
requirements to power them on.

-- 
With best wishes
Dmitry