wkup_m3_ipc: Add support for toggling VTT regulator
authorDave Gerlach <d-gerlach@ti.com>
Fri, 2 Nov 2018 10:29:06 +0000 (15:59 +0530)
committerTero Kristo <t-kristo@ti.com>
Tue, 6 Nov 2018 13:06:17 +0000 (15:06 +0200)
commitb6aef1c5439b0e76c8e0cc8f0bf0b4c1ee2c53bc
treec2ce40f7153c13f8dd74a4cae3fccf2124bf9aa8
parent1fc39d6bbad8a8c46b853b77761309de7fdead6e
wkup_m3_ipc: Add support for toggling VTT regulator

Some boards (currently AM335x EVM-SK) provides s/w control via
GPIO to toggle VTT regulator to reduce power consumption in low
power state.

The VTT regulator should be disabled after enabling self-refresh on
suspend, and should be enabled before disabling self-refresh on resume.
This is to allow proper self-refresh entry/exit commands to be
transmitted to the memory.

Add support for toggling VTT regulator using DT properties.
Actual toggling happens in CM3 Firmware. The enable option & the GPIO
pin used is collected in A8 Core and then sent to CM3 using IPC
registers.

Note:
Here it is assumed that VTT Toggle will be done using a pin on GPIO-0
Instance. The reason is GPIO-0 is in wakeup domain.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>
Documentation/devicetree/bindings/soc/ti/wkup_m3_ipc.txt
drivers/soc/ti/wkup_m3_ipc.c
include/linux/wkup_m3_ipc.h