Messages in this thread | | | From | Linus Walleij <> | Date | Thu, 18 Jan 2018 11:16:44 +0100 | Subject | Re: [RESEND RFC PATCH 0/2] fixing the gpio ownership |
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Hi Ludovic, thanks for your patches!
On Mon, Jan 15, 2018 at 5:24 PM, Ludovic Desroches <ludovic.desroches@microchip.com> wrote:
> A few weeks ago, I have sent an RFC about adding bias support for GPIOs [1].
I was confused I think, because the issue of ownership and adding bias support were conflated.
I think I discussed properly the ideas I have for pin control properties vs the GPIOlib API/ABI in my response to patch 1.
> It was motivated by the fact that I wanted to enable the pinmuxing strict mode > for my pin controller which can muxed a pin as a peripheral or as a GPIO.
So that is a different thing from bias support.
> Enabling the strict mode prevents several devices to be probed because > requesting a GPIO fails. The pin request function complains about the > ownership of the GPIO which is different from the mux ownership. I have to > remove my pinctrl node to avoid this conflict but I need it to configure my > pins and to set a pull-up bias for my GPIOs.
Okay I think the right solution is to fix the ownership issue, and set up bias using pin control/config but use the line through gpiolib for now.
> The main issue is that enabling the strict mode will > break old DTBs.
Yeah we need to work around that.
> I was going to submit patches for this but, after using the > sysfs which still show me a bad ownership, I decided that it should be fixed.
Yep :)
> So I did these patches. Unfortunately, there are several ways to lead to > gpiod_request(). It does the trick only for the gpiod_get family. The issue is > still present with legacy gpio_request and fwnode_get_named_gpiod.
fwnode_get_named_gpiod() must really be fixed too. You probably want to have things like LEDs and GPIO keys working even if your pin controller is strict.
I don't care so much about the old functions, I guess you just have to make sure that the drivers for *your* pin controller all use descriptors so that you can enable strict mode on *your* pin controller, right?
Restrict your task to this, I'd say.
> It seems > that more and more drivers are converted to use GPIO descriptors so there is > some hope.
Yeah I'm doing this when I have time. There is plenty of work... Help appreciated.
Yours, Linus Walleij
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