On Sun, Jan 18, 2015 at 10:04:38AM +0000, Lee Jones wrote: > On Thu, 15 Jan 2015, Linus Walleij wrote: > > > On Tue, Jan 13, 2015 at 3:42 AM, Andrew Lunn <[email protected]> wrote: > > > > > 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. > > > > Good point. > > > > > I think the only sensible way to achieve this is that the gpio driver > > > keeps its existing binding. > > > > Yup. > > > > > This does not really describe the hardware. The hardware is more like: > > > > > > gpio: gpio { > > > compatible = "marvell,orion-gpio"; > > > reg = <0xd0018100 0x40>; > > > ngpios = <32>; > > > gio-controller; > > > #gpio-cells = <2>; > > > interrupt-controller; > > > #interrupt-cells = <2>; > > > interrupts = <16>, <17>, <18>, <19>; > > > clocks = <&coreclk 0>; > > > > > > pwm: pwm { > > > compatible = "marvell,armada-pwm"; > > > reg = <0xd00181c0 0x08>; > > > #pwm-cells = <2>; > > > clocks = <&coreclk 0>; > > > }; > > > };
I think you technically need an (empty) ranges property in the gpio node so that the address can be properly translated. > > > > > > but i don't think MFD supports that sort of structure? > > > > No it would have to be some custom DT code in the GPIO driver > > spawning the PWM platform device. > > of_platform_populate()? Huh? I was under the impression that mfd_add_devices() would already deal with this situation? Isn't that what's parsed based on the cells parameter? Thierry
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