[PATCH] thinkpad_acpi: Add sysfs entry for lcdshadow feature

[Andy Shevchenko]

On Thu, Feb 20, 2020 at 9:48 AM Nitin Joshi <nitjoshi at gmail.com> 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.

[1]: https://lore.kernel.org/dri-devel/CAL_quvRknSSVvXN3q_Se0hrziw2oTNS3ENNoeHYhvciCRq9Yww@mail.gmail.com/


--
With Best Regards,
Andy Shevchenko