On Mon, Dec 11, 2023 at 06:49:02PM +0100, Andrew Lunn wrote:
> On Mon, Dec 11, 2023 at 06:19:46PM +0100, Christian Marangi wrote:
> > On Mon, Dec 11, 2023 at 04:54:12PM +0100, Andrew Lunn wrote:
> > > > Mhhh with a generic property and LED core or phylib handling it... How
> > > > it would work applying that setting on PHY side?
> > >
> > > Add a .led_set_polarity callback to the PHY driver structure?
> > >
> > > Take a look at other LED drivers. Does anything similar already exist?
> > > It is unlikely that PHYs are the only sort of LED to have a polarity.
> > >
> >
> > Interesting topic... With a quick grep on Documentation for polarity of
> > high, I can't find any use of it...
>
> As i said, active-high is the default. So there is no need to specify
> it. But if you look in Documentation/devicetree/binding/leds for
> 'active-low' you will find a few examples.
>
Yes I was searching more and I just notice active-low and led-active-low
usage for bcm6358.
> > Also main problem is that the thing is controlled globally and not per
> > LED. (can be handled internally to the driver with some priv and check
> > magic)
>
> Ah, missed that. Marvell PHYs have polarity per LED.
>
> It would be better to describe this correctly, so one property at a
> higher level. We can then in the future add an 'active-low' property
> per PHY.
>
> > Is it worth to impemement the additional API to control this? And I
> > guess a egenric binding should be added to ethernet-phy? Or should it be
> > added to LEDs?
>
> Since it is above individual LEDs, i would not add it to the generic
> LED binding. But it could go inside the leds object of
> ethernet-phy.yaml.
>
> leds {
> #address-cells = <1>;
> #size-cells = <0>;
>
> active-low;
>
> led@0 {
> reg = <0>;
> color = <LED_COLOR_ID_WHITE>;
> function = LED_FUNCTION_LAN;
> default-state = "keep";
> };
>
Ok! And I guess the additional API will (initially to be later expanded
for other usage?) take this value and call the set polarity based on
this correct?
bool active_low = of_property_read_bool(leds_node, "active-low");
.led_set_polarity(struct phy_device *phydev, bool active_low);
Maybe a more flexible approach might be scan for both. (either in leds
node or in the led subnode)
.led_set_polarity(struct phy_device *phydev, int index, bool active_low);
Where index is -1 if it's global and the led index if it's in the led
node?
PHY driver will know what to ignore/use as I can't immagine to have a
PHY that have both global and per LED polarity. What do you think?
--
Ansuel
