Messages in this thread | | | From | Flavio Suligoi <> | Subject | RE: How to use an ACPI declared GPIO in a userspace ... | Date | Wed, 30 Sep 2020 12:04:43 +0000 |
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Hi Andy,
> > > > > I was wondering if there is a generic GPIO driver that I can use > Maybe I was not so clear, but as Bart mentioned the least you can do > is simply define line name via "gpio-line-names" property. The problem > here is when and how you would like to have them incorporated.
I already tried adding the "gpio-line-names" property, but the problem is the same: no driver asks for this GPIO, as shown by the following kernel messages:
ACPI: Host-directed Dynamic ACPI Table Load: ACPI: SSDT 0xFFFF994034D42A00 0000E8 (v05 ASEMsp GPIO_BTN 00000001 INTL 20200717) ACPI: \_SB_.GPO1.BTNS: PRP0001 requires 'compatible' property
So I'll start to write a simple device driver to use this GPIO. I'll keep you informed! > When: if ACPI tables are being provided by firmware which you may not > alter, then you must use initramfs type of solution (no configfs, > don't know about EFI var though). How: In that case you might have a > chance to incorporate _DSD() method into *existing* _CRS() one. > Possible impediments: if ACPI table from firmware already has a _DSD() > defined or above is not working for some reason. In such a case you > must upgrade entire DSDT via initramfs. > > > > > Adding Andy who knows ACPI GPIO well. > > > > > > Thanks. > > > > > > > In general, the "gpio-line-names" property is used for that and it's > > > > supported both for device tree as well as ACPI, although I have only > > > > ever used the former. > > > > > > Right. ACPI supports properties via _DSD() method. > > -- > With Best Regards, > Andy Shevchenko
Thanks Andy and Bartosz for your support! Best regards,
Flavio
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