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Message-ID: <20230425103040.znv66k364ant6klq@bogus>
Date: Tue, 25 Apr 2023 11:30:40 +0100
From: Sudeep Holla <sudeep.holla@....com>
To: Arnd Bergmann <arnd@...db.de>, Huisong Li <lihuisong@...wei.com>
Cc: Bjorn Andersson <andersson@...nel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
Sudeep Holla <sudeep.holla@....com>,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>,
Shawn Guo <shawnguo@...nel.org>, linux-kernel@...r.kernel.org,
soc@...nel.org, wanghuiqiang@...wei.com, tanxiaofei@...wei.com,
liuyonglong@...wei.com, huangdaode@...wei.com,
linux-acpi@...r.kernel.org, Len Brown <lenb@...nel.org>,
"Rafael J. Wysocki" <rafael@...nel.org>,
devicetree@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
Frank Rowand <frowand.list@...il.com>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
Subject: Re: [PATCH] soc: hisilicon: Support HCCS driver on Kunpeng SoC
Thanks Arnd for cc-ing the ALKML.
On Mon, Apr 24, 2023 at 10:09:47AM +0200, Arnd Bergmann wrote:
> On Mon, Apr 24, 2023, at 09:30, Huisong Li wrote:
[...]
> > +
> > +static int hccs_get_device_property(struct hccs_dev *hdev)
> > +{
> > + struct device *dev = hdev->dev;
> > +
> > + if (device_property_read_u32(dev, "device-flags", &hdev->flags)) {
> > + dev_err(hdev->dev, "no device-flags property.\n");
> > + return -ENODEV;
> > + }
> > +
> > + if (device_property_read_u8(dev, "pcc-type", &hdev->type)) {
> > + dev_err(hdev->dev, "no pcc-type property.\n");
> > + return -ENODEV;
> > + }
> > +
> > + if (device_property_read_u32(dev, "pcc-chan-id", &hdev->chan_id)) {
> > + dev_err(hdev->dev, "no pcc-channel property.\n");
> > + return -ENODEV;
> > + }
> > +
> > + hdev->intr_mode = hccs_get_bit(hdev->flags, HCCS_DEV_FLAGS_INTR_B);
> > + if (!hccs_dev_property_supported(hdev))
> > + return -EOPNOTSUPP;
> > +
>
> Where are the device properties documented? I'm never quite sure how
> to handle these for ACPI-only drivers, since we don't normally have the
> bindings in Documentation/devicetree/bindings/, but it feels like there
> should be some properly reviewed document somewhere else.
>
> Adding ACPI and devicetree maintainers to Cc for clarification.
Why are these DSD style properties added here ? Why can't we just make
use of _CRS with Generic Address Structure(GAS) register entry for each
of the PCC channel which eliminates the need of "pcc-chan-id". The type
must be deduced from the order in the list of _CRS if needed. I don't
quite understand what magic the flags contain here to provide any info
there.
--
Regards,
Sudeep
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