From: Mark Brown <broonie@kernel.org>
To: Jim Quinlan <jim2101024@gmail.com>
Cc: Rob Herring <robh@kernel.org>,
Jim Quinlan <james.quinlan@broadcom.com>,
linux-pci <linux-pci@vger.kernel.org>,
Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
bcm-kernel-feedback-list <bcm-kernel-feedback-list@broadcom.com>,
Florian Fainelli <f.fainelli@gmail.com>,
Bjorn Helgaas <bhelgaas@google.com>,
"moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE"
<linux-rpi-kernel@lists.infradead.org>,
"moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/6] dt-bindings: PCI: Add bindings for Brcmstb EP voltage regulators
Date: Tue, 5 Jan 2021 15:33:47 +0000 [thread overview]
Message-ID: <20210105153347.GE4487@sirena.org.uk> (raw)
In-Reply-To: <CANCKTBtNgyBTNwwtbtMkR9nFwq+AZyAZmGX9XXfhwf27zwjG_Q@mail.gmail.com>
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On Tue, Jan 05, 2021 at 10:09:21AM -0500, Jim Quinlan wrote:
> On Tue, Jan 5, 2021 at 9:01 AM Mark Brown <broonie@kernel.org> wrote:
> > > For us, the supplies are for the EP chip's power. We have the PCIe
> > > controller turning them "on" for power-on/resume and "off" for
> > > power-off/suspend. We need the "xxx-supply" property in the
> > > controller's DT node because of the chicken-and-egg situation: if the
> > > property was in the EP's DT node, the RC will never discover the EP
> > > to see that there is a regulator to turn on. We would be happy with
> > Why can't the controller look at the nodes describing devices for
> > standard properties?
> It just feels wrong for the driver (RC) of one DT node to be acting on
> a property of another driver's (EP) node, even though it is a subnode.
This is something we do for other buses, for example where there's
device specific tuning that is actually implemented in the controller
hardware.
> There is also the possibility of the EP driver acting upon the
> property simultaneously; we don't really have control of what EP
> device and drivers are paired with our SOCs.
If the device is trying to do something with a supply that's a standard
part of the bus outside of the bus it seems like that's going to lead to
problems no matter what, due to the discovery issues the device must be
coordinating with the bus somehow.
> In addition, this just pushes the binding name issue down a level --
> what should these power supplies be called? They are not slot power
> supplies. Can the Broadcom STB PCIe RC driver's binding document
> specify and define the properties of EP sub-nodes?
I assume the supplies have some name in the PCI specs, whatever names
are used there would probably be appropriate.
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next prev parent reply other threads:[~2021-01-05 15:35 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 21:11 [PATCH v2 0/6] brcmstb: add EP regulators and panic handler Jim Quinlan
2020-11-30 21:11 ` [PATCH v2 1/6] dt-bindings: PCI: Add bindings for Brcmstb EP voltage regulators Jim Quinlan
2020-12-09 14:01 ` Rob Herring
2021-01-04 22:12 ` Jim Quinlan
2021-01-05 14:01 ` Mark Brown
2021-01-05 15:09 ` Jim Quinlan
2021-01-05 15:33 ` Mark Brown [this message]
2021-01-07 22:31 ` Rob Herring
2020-11-30 21:11 ` [PATCH v2 2/6] PCI: brcmstb: Add control of EP voltage regulator(s) Jim Quinlan
2020-11-30 21:32 ` Florian Fainelli
2020-11-30 21:11 ` [PATCH v2 3/6] PCI: brcmstb: Do not turn off regulators if EP can wake up Jim Quinlan
2020-11-30 21:29 ` Florian Fainelli
2020-11-30 21:11 ` [PATCH v2 4/6] PCI: brcmstb: Give 7216 SOCs their own config type Jim Quinlan
2020-11-30 21:24 ` Florian Fainelli
2020-11-30 21:11 ` [PATCH v2 5/6] PCI: brcmstb: Add panic/die handler to RC driver Jim Quinlan
2020-11-30 21:28 ` Florian Fainelli
2020-12-01 18:05 ` Bjorn Helgaas
2020-12-01 20:12 ` Jim Quinlan
2021-01-06 19:19 ` Bjorn Helgaas
[not found] ` <CA+-6iNzARUT63Mv7qFzk_g5wep4v6aPuN8f8yjQcgozVcKhVTw@mail.gmail.com>
2021-01-06 19:57 ` Jim Quinlan
2021-01-06 23:11 ` Bjorn Helgaas
2020-11-30 21:11 ` [PATCH v2 6/6] PCI: brcmstb: check return value of clk_prepare_enable() Jim Quinlan
2020-11-30 21:24 ` Florian Fainelli
2021-01-06 19:19 ` [PATCH v2 0/6] brcmstb: add EP regulators and panic handler Bjorn Helgaas
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