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Message-ID: <b1a3f887fd037fd18c45ac020c6142cedba58ca7.camel@icenowy.me>
Subject: Re: [PATCH] PCI: fu740: do not use clock name when requesting clock
From:   Icenowy Zheng <uwu@icenowy.me>
To:     Conor.Dooley@microchip.com, paul.walmsley@sifive.com,
        greentime.hu@sifive.com, lpieralisi@kernel.org, robh@kernel.org,
        kw@linux.com, bhelgaas@google.com
Cc:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-riscv@lists.infradead.org
Date:   Mon, 12 Sep 2022 09:38:28 +0800
In-Reply-To: <8d7b8514-efe0-d3e3-8458-f4f003f10154@microchip.com>
References: <20220907054020.745672-1-uwu@icenowy.me>
         <8d7b8514-efe0-d3e3-8458-f4f003f10154@microchip.com>
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=E5=9C=A8 2022-09-08=E6=98=9F=E6=9C=9F=E5=9B=9B=E7=9A=84 18:14 +0000=EF=BC=
=8CConor.Dooley@microchip.com=E5=86=99=E9=81=93=EF=BC=9A
> On 07/09/2022 06:40, Icenowy Zheng wrote:
> > EXTERNAL EMAIL: Do not click links or open attachments unless you
> > know the content is safe
> >=20
> > The DT binding of FU740 PCIe does not enforce a clock-names property,
> > and there exist some device tree that has a clock name that does not
> > stick to the one used by Linux DT (e.g. the one shipped with current
> > U-Boot mainline).
>=20
> I recently added the missing enforcement:
> https://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/pci.git/commit=
/?h=3Dpci/dt&id=3Db408fad61d34c765c3e01895286332af2d50402a

Unfortunately binding w/o clock-names enforcement has already entered a
stable release (5.19), and the real clock name "pcie_aux" is never
enforced before (there's a DT in U-Boot that uses "pcieaux" instead),
should this be considered as breakage to stable DT binding?

Anyway, I had sent out a patch that synchorizes all FU740-related DT
files to U-Boot, see [1].

[1]
https://lore.kernel.org/all/20220825081119.1694007-2-uwu@icenowy.me/

>=20
> Since there's only one clock though, I'd imagine it makes little to no
> real difference if the check here is relaxed.
>=20
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
>=20
> >=20
> > Drop the name in the clock request, instead just pass NULL (because
> > this device should have only a single clock).
> >=20
> > Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
> > ---
> > =C2=A0drivers/pci/controller/dwc/pcie-fu740.c | 2 +-
> > =C2=A01 file changed, 1 insertion(+), 1 deletion(-)
> >=20
> > diff --git a/drivers/pci/controller/dwc/pcie-fu740.c
> > b/drivers/pci/controller/dwc/pcie-fu740.c
> > index 0c90583c078b..edb218a37a4f 100644
> > --- a/drivers/pci/controller/dwc/pcie-fu740.c
> > +++ b/drivers/pci/controller/dwc/pcie-fu740.c
> > @@ -315,7 +315,7 @@ static int fu740_pcie_probe(struct
> > platform_device *pdev)
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0 return dev_err_probe(dev, PTR_ERR(afp->pwren),
> > "unable to get pwren-gpios\n");
> >=20
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 /* Fetch clocks */
> > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 afp->pcie_aux =3D devm_clk_get(de=
v, "pcie_aux");
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 afp->pcie_aux =3D devm_clk_get(de=
v, NULL);
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (IS_ERR(afp->pcie_aux))
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0 return dev_err_probe(dev, PTR_ERR(afp->pcie_aux),
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 "pcie_aux clock source
> > missing or invalid\n");
> > --
> > 2.37.1
> >=20
>=20