[lkml]   [2020]   [Sep]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectHow to use an ACPI declared GPIO in a userspace ...
Hi all,

I need to expose to the userspace a GPIO, physically connected to a board
push-button. This GPIO must expose a pre-defined name, such as
"user-push-button", so that the userspace applications can use it without
know any physical GPIO details.

I can customize the board BIOS and so my goal is to add an ACPI table with
a content like this:

Scope (\_SB.GPO1)
Device (BTNS)
Name (_HID, "PRP0001")
Name (_DDN, "GPIO buttons device")

Name (_CRS, ResourceTemplate ()
GpioIo (
Exclusive, // Not shared
PullNone, // No need for pulls
0, // Debounce timeout
0, // Drive strength
IoRestrictionInputOnly, // Only used as input
"\\_SB.GPO1", // GPIO controller
0, ResourceConsumer, , ) // Must be 0
25, // GPIO number

I know that this GPIO can be used from other drivers.
For example I successfully tested it using the "gpio-keys" device driver,
giving to my GPIO a key-code and emulating in this way a keyboard key.
This could be a possible solution.

But I prefer to expose my GPIO as a classic GPIO, not as a keyboard key.

I was wondering if there is a generic GPIO driver that I can use to expose
this GPIO with its pre-defined name (caming from the ACPI table declaration),
to the userspace...

Best regards,


 \ /
  Last update: 2020-09-29 17:43    [W:0.053 / U:4.368 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site