mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-29 05:44:11 +00:00
f226041424
Some boards like the AM335x EVM-SK and AM437x GP EVM provide software control via a GPIO pin to toggle the DDR VTT regulator to reduce power consumption in low power states. 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. The "ti,vtt-gpio-pin" device tree property in the wkup_m3_ipc node specifies which GPIO pin to use. This property is communicated to the Wakeup Cortex M3 co-processor where the actual toggling of the GPIO pin happens in CM3 firmware [1]. Please note that the GPIO pin must be on the GPIO0 module as that module is in the wakeup power domain. [1] https://git.ti.com/cgit/processor-firmware/ti-amx3-cm3-pm-firmware/tree/src/pm_services/ddr.c?h=08.02.00.006#n190 Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Signed-off-by: Keerthy <j-keerthy@ti.com> [dfustini: remove the unnecessary "ti,needs-vtt-toggle" property] Signed-off-by: Drew Fustini <dfustini@baylibre.com> Signed-off-by: Nishanth Menon <nm@ti.com> Link: https://lore.kernel.org/r/20220409211215.2529387-3-dfustini@baylibre.com |
||
---|---|---|
.. | ||
acpi | ||
asm-generic | ||
clocksource | ||
crypto | ||
drm | ||
dt-bindings | ||
keys | ||
kunit | ||
kvm | ||
linux | ||
math-emu | ||
media | ||
memory | ||
misc | ||
net | ||
pcmcia | ||
ras | ||
rdma | ||
scsi | ||
soc | ||
sound | ||
target | ||
trace | ||
uapi | ||
vdso | ||
video | ||
xen |