Re: about pca955x led driver gpio management

[Andrea Scian - DAVE Embedded Systems]

Il 24/10/2017 07:51, Cédric Le Goater ha scritto:
> On 10/17/2017 11:16 AM, Andrea Scian - DAVE Embedded Systems wrote:
> > > On 10/17/2017 10:20 AM, Andrea Scian - DAVE Embedded Systems wrote:
> > > > Il 17/10/2017 10:18, Cédric Le Goater ha scritto:
> > > > > On 10/17/2017 09:36 AM, Andrea Scian - DAVE Embedded Systems wrote:
> > > > > > Dear all,
> > > > > >
> > > > > > I'm working on an iMX6 based board with a PCA9555 which is used both to drive LEDs and manage some GPIOs.
> > > > > The PCA9555 chip and the PCA955[0-3] chips have different control
> > > > > registers. You need a different led driver for it.
> > > >
> > > > My typo sorry, as you can see in the device tree below, I'm using pca9551
> > >
> > > ok.
> > >
> > > You might want to take a look at how we mixed gpios and leds on the witherspoon
> > > system using pca9552 chips. we added a gpio-leds binding.
> > >
> > > https://github.com/openbmc/linux/blob/dev-4.10/arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dts
> >
> > understood: you configure all pins of PCA955x as GPIOs and the map the one you need as led with gpio-leds binding.
>
> Sorry I got distracted.
>
> > However to me this is a kind of workaround or, at least, there's nothing about this limitation into the devicetree binding (in fact, IMHO, the device tree binding example will just fail)
>
> euh ? what do you mean. There is a real system using this device tree.
> I think we would know about it if it didn't work. Please explain

I mean that, for what I understand, your configuration is working 
because all pin of 9551 are configured as GPIOs (and the binded back as led)
In my configuration I have some pins configured as led and some as 
GPIOs, and this is not working.

> > I wrote the attached patch which should fix the issue and allow a more generic approach. WDYT?
> >
> > (in case it looks good, I'll send the patch in the correct way)
>
> Please send the patch to discuss, add Andrew Jeffery <andrew@xxxxxxxx>
> in cc:

Sorry for the delay but I'm busy in Prague with OSSummit and ELCE. I'll 
send a proper patch and more comments, if needed, by the begin of next week.

(BTW, if some of you are here, drop me a line and have a beer together! 
;-) )