On Wed, 09 Oct 2024, Lorenzo Bianconi wrote:
> On Oct 02, Lee Jones wrote:
> > On Tue, 01 Oct 2024, Lorenzo Bianconi wrote:
> >
> > > From: Christian Marangi <ansuelsmth@xxxxxxxxx>
> > >
> > > Support for Airoha EN7581 Multi Function Device that
> > > expose PINCTRL functionality and PWM functionality.
> >
> > The device is a jumble of pinctrl registers, some of which can oscillate.
> >
> > This is *still* not an MFD.
> >
> > If you wish to spread this functionality over 2 drivers, use syscon to
> > obtain the registers and simple-mfd to automatically probe the drivers.
>
> Hi Lee,
>
> IIUC you are suggesting two possible approaches here:
>
> 1- have a single driver implementing both pinctrl and pwm functionalities.
> This approach will not let us reuse the code for future devices that
> have just one of them in common, like pwm (but we can live with that).
If you can have one without the other, then they are separate devices.
> 2- use a device node like the one below (something similar to [0])
>
> system-controller@1fbf0200 {
> compatible = "syscon", "simple-mfd";
> reg = <0x0 0x1fbf0200 0x0 0xc0>;
>
> interrupt-parent = <&gic>;
> interrupts = <GIC_SPI 26 IRQ_TYPE_LEVEL_HIGH>;
>
> gpio-controller;
> #gpio-cells = <2>;
>
> interrupt-controller;
> #interrupt-cells = <2>;
>
> pio: pinctrl {
> compatible = "airoha,en7581-pinctrl";
>
> [ some pinctrl properties here ]
> };
>
> #pwm-cells = <3>;
>
> pwm {
> compatible = "airoha,en7581-pwm";
> };
> };
>
> Please correct me if I am wrong, but using syscon/simple-mfd as compatible
> string for the 'parent' device, will require to introduce the compatible strings
> even for the child devices in order to probe them, correct?
> If so, as pointed out by Christian, this is something nacked by Rob/Krzysztof/Conor
> (this is the main reason why we introduced a full mfd driver here).
>
> @Rob, Krzysztof, Conor: am I right?
I don't see why separate functionality shouldn't have separate
compatible strings, even if the registers are together. Register layout
and functionality separation are not related.
--
Lee Jones [李琼斯]
