Re: [PATCH] thinkpad_acpi: Add sysfs entry for lcdshadow feature

From: Andy Shevchenko
Date: Thu Feb 20 2020 - 05:43:04 EST

On Thu, Feb 20, 2020 at 9:48 AM Nitin Joshi <nitjoshi@xxxxxxxxx> wrote:
> This feature is supported on some Thinkpad products like T490s, Thinkpad
> X1 yoga 4th Gen etc . The lcdshadow feature can be enabled and disabled
> when user press "Fn" + "D" key. Currently, no user feedback is given for
> this action. Adding as sysfs entry allows userspace to show an On Screen
> Display whenever the setting changes.
> Summary of changes is mentioned below :
> - Added TP_HKEY_EV_LCDSHADOW_CHANGED for consistency inside the driver
> - Added unmapped LCDSHADOW to keymap
> - Added lcdshadow_get function to read value using ACPI
> - Added lcdshadow_refresh function to re-read value and send notification
> - Added sysfs group creation to tpaci_lcdshadow_init
> - Added lcdshadow_exit to remove sysfs group again
> - Implemented lcdshadow_enable_show/lcdshadow_enable_store
> - Added handler to tpacpi_driver_event to update refresh lcdshadow
> - Explicitly call tpacpi_driver_event for extended keyset

Adding custom PrivacyGuard support to this driver was my mistake,
There is a discussion [1] how to do this in generic way to cover other
possible users.
I Cc this to people from that discussion.


With Best Regards,
Andy Shevchenko