From mboxrd@z Thu Jan  1 00:00:00 1970
From: Lee Jones <lee.jones@linaro.org>
Subject: Re: [PATCH 3/7] gpio: mvebu: Add limited PWM support
Date: Sun, 18 Jan 2015 10:04:38 +0000
Message-ID: <20150118100438.GC3574@x1>
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To: Linus Walleij <linus.walleij@linaro.org>
Cc: Andrew Lunn <andrew@lunn.ch>, Thierry Reding <thierry.reding@gmail.com>, "linux-pwm@vger.kernel.org" <linux-pwm@vger.kernel.org>, Samuel Ortiz <sameo@linux.intel.com>, Thomas Petazzoni <thomas.petazzoni@free-electrons.com>, Imre Kaloz <kaloz@openwrt.org>, Gregory Clement <gregory.clement@free-electrons.com>, Sebastian Hesselbarth <sebastian.hesselbarth@googlemail.com>, "linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>
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On Thu, 15 Jan 2015, Linus Walleij wrote:

> On Tue, Jan 13, 2015 at 3:42 AM, Andrew Lunn <andrew@lunn.ch> wrote:
>=20
> > So i thought about this some more. What would an MFD based solution
> > look like?
> >
> > First issue is backwards compatibility. There are currently around =
90
> > .dts files using this gpio driver. I could imagine a few of these
> > being changed to make use of an MFD based driver to make us of the =
new
> > features, but the rest expect backwards compatibility.
>=20
> Good point.
>=20
> > I think the only sensible way to achieve this is that the gpio driv=
er
> > keeps its existing binding.
>=20
> Yup.
>=20
> > This does not really describe the hardware. The hardware is more li=
ke:
> >
> >         gpio: gpio {
> >                 compatible =3D "marvell,orion-gpio";
> >                 reg =3D <0xd0018100 0x40>;
> >                 ngpios =3D <32>;
> >                 gio-controller;
> >                 #gpio-cells =3D <2>;
> >                 interrupt-controller;
> >                 #interrupt-cells =3D <2>;
> >                 interrupts =3D <16>, <17>, <18>, <19>;
> >                 clocks =3D <&coreclk 0>;
> >
> >                 pwm: pwm {
> >                         compatible =3D "marvell,armada-pwm";
> >                         reg =3D <0xd00181c0 0x08>;
> >                         #pwm-cells =3D <2>;
> >                         clocks =3D <&coreclk 0>;
> >                 };
> >         };
> >
> > but i don't think MFD supports that sort of structure?
>=20
> No it would have to be some custom DT code in the GPIO driver
> spawning the PWM platform device.

of_platform_populate()?

--=20
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org =E2=94=82 Open source software for ARM SoCs
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