From: Chuanjia Liu <chuanjia.liu@mediatek.com>
To: Rob Herring <robh+dt@kernel.org>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Ryder Lee <ryder.lee@mediatek.com>,
"Jianjun Wang" <jianjun.wang@mediatek.com>,
Yong Wu <yong.wu@mediatek.com>, PCI <linux-pci@vger.kernel.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@lists.infradead.org>,
<devicetree@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v12 2/6] PCI: mediatek: Add new method to get shared pcie-cfg base address
Date: Thu, 2 Sep 2021 17:34:08 +0800 [thread overview]
Message-ID: <eb855d186d572e8a0343456bb5d76797f8f3870f.camel@mediatek.com> (raw)
In-Reply-To: <CAL_Jsq+dBi-XUDJD_STP=jWw+RLkRpX1U9XsRMhqK4U1H=0FHw@mail.gmail.com>
On Tue, 2021-08-31 at 10:17 -0500, Rob Herring wrote:
> On Mon, Aug 30, 2021 at 10:31 PM Chuanjia Liu <
> chuanjia.liu@mediatek.com> wrote:
> >
> > On Mon, 2021-08-30 at 16:43 -0500, Bjorn Helgaas wrote:
> > > On Mon, Aug 30, 2021 at 03:09:44PM +0800, Chuanjia Liu wrote:
> > > > On Fri, 2021-08-27 at 11:46 -0500, Bjorn Helgaas wrote:
> > > > > On Mon, Aug 23, 2021 at 11:27:56AM +0800, Chuanjia Liu wrote:
> > > > > > @@ -995,6 +1004,14 @@ static int
> > > > > > mtk_pcie_subsys_powerup(struct
> > > > > > mtk_pcie *pcie)
> > > > > > return PTR_ERR(pcie->base);
> > > > > > }
> > > > > >
> > > > > > + cfg_node = of_find_compatible_node(NULL, NULL,
> > > > > > + "mediatek,generi
> > > > > > c-
> > > > > > pciecfg");
> > > > > > + if (cfg_node) {
> > > > > > + pcie->cfg =
> > > > > > syscon_node_to_regmap(cfg_node);
> > > > >
> > > > > Other drivers in drivers/pci/controller/ use
> > > > > syscon_regmap_lookup_by_phandle() (j721e, dra7xx, keystone,
> > > > > layerscape, artpec6) or syscon_regmap_lookup_by_compatible()
> > > > > (imx6,
> > > > > kirin, v3-semi).
> > > > >
> > > > > You should do it the same way unless there's a need to be
> > > > > different.
> > > >
> > > > I have used phandle, but Rob suggested to search for the node
> > > > by
> > > > compatible.
> > > > The reason why syscon_regmap_lookup_by_compatible() is not
> > > > used here is that the pciecfg node is optional, and there is no
> > > > need to
> > > > return error when the node is not searched.
> > >
> > > How about this?
> > >
> > > regmap = syscon_regmap_lookup_by_compatible("mediatek,generic-
> > > pciecfg");
> > > if (!IS_ERR(regmap))
> > > pcie->cfg = regmap;
>
> +1
>
> >
> > Hi Bjorn,
> >
> > We need to deal with three situations
> > 1) No error
> > 2) The error of the node not found, don't do anything
> > 3) Other errors, return errors
> >
> > I guess you mean
> >
> > regmap = syscon_regmap_lookup_by_compatible("mediatek,generic-
> > pciecfg");
> > if (!IS_ERR(regmap))
> > pcie->cfg = regmap;
> > else if (IS_ERR(regmap) && PTR_ERR(regmap) != -ENODEV)
>
> You already know IS_ERR is true here.
>
> > return PTR_ERR(regmap);
>
> syscon_regmap_lookup_by_compatible_optional is the function you are
> looking for. The _optional flavor doesn't exist, so create it. There
> is one for the phandle lookup.
>
> >
> > I'm not sure if we need this, it seems a little weird and there are
> > many drivers in other subsystems that use syscon_node_to_regmap().
>
> You are implementing the exact same sequence that
> syscon_regmap_lookup_by_compatible() does, so clearly you should be
> using it. The one difference is you forgot the of_node_put().
Hi,Rob
Thanks for your explanation. You're right.
Now I understand use syscon_regmap_lookup_by_compatible() is a better
way. I'll follow your advice
regmap = syscon_regmap_lookup_by_compatible("mediatek,generic-
pciecfg");
if (!IS_ERR(regmap))
pcie->cfg = regmap;
else if (PTR_ERR(regmap) != -ENODEV)
return PTR_ERR(regmap);
Best regards
Chuanjia
>
> Rob
>
> _______________________________________________
> Linux-mediatek mailing list
> Linux-mediatek@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-mediatek
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next prev parent reply other threads:[~2021-09-02 9:38 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-23 3:27 [PATCH v12 0/6] PCI: mediatek: Spilt PCIe node to comply with hardware design Chuanjia Liu
2021-08-23 3:27 ` [PATCH v12 1/6] dt-bindings: PCI: mediatek: Update the Device tree bindings Chuanjia Liu
2021-08-23 3:27 ` [PATCH v12 2/6] PCI: mediatek: Add new method to get shared pcie-cfg base address Chuanjia Liu
2021-08-27 16:46 ` Bjorn Helgaas
2021-08-30 7:09 ` Chuanjia Liu
2021-08-30 21:43 ` Bjorn Helgaas
2021-08-31 3:31 ` Chuanjia Liu
2021-08-31 15:17 ` Rob Herring
2021-09-02 9:34 ` Chuanjia Liu [this message]
2021-08-31 15:04 ` Rob Herring
2021-08-31 15:47 ` Bjorn Helgaas
2021-08-31 18:24 ` Rob Herring
2021-08-23 3:27 ` [PATCH v12 3/6] PCI: mediatek: Add new method to get irq number Chuanjia Liu
2021-08-31 18:30 ` Bjorn Helgaas
2021-09-02 9:28 ` Chuanjia Liu
2021-08-23 3:27 ` [PATCH v12 4/6] PCI: mediatek: Get pci domain and decide how to parse node Chuanjia Liu
2021-08-23 3:27 ` [PATCH v12 5/6] arm64: dts: mediatek: Split PCIe node for MT2712 and MT7622 Chuanjia Liu
2021-09-21 18:43 ` Matthias Brugger
2021-08-23 3:28 ` [PATCH v12 6/6] ARM: dts: mediatek: Update MT7629 PCIe node for new format Chuanjia Liu
2021-09-21 18:43 ` Matthias Brugger
2021-08-26 12:53 ` [PATCH v12 0/6] PCI: mediatek: Spilt PCIe node to comply with hardware design Lorenzo Pieralisi
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