linux/arch/arm/mach-at91
Claudiu Beznea 9f7195da31 power: reset: at91-poweroff: switch to slow clock before shutdown
The SAMA5D2 NRST input signal is resynchronized with the SLCK clock and it
can take up to 2 SLCK cycles (about 90us) for the internal reset to be
effective. During this delay, the VDDCORE current consumption may still be
high (application-dependent) with the VDDCORE regulator already OFF. Under
such conditions, VDDCORE may operate below its operating range leading to
potential register corruption.

To prevent such situation, it is recommended to decrease significantly the
power consumption of the device once the voltage regulator is  turned-off.
This can be achieved by operating the device at a much lower low frequency.

To solve this switch the master clock to slock clock just before writing
shutdown command to shutdown controller.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Suggested-by: Patrice Vilchez <patrice.vilchez@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2018-09-16 12:31:48 +02:00
..
Kconfig clk: at91: add I2S clock mux driver 2018-07-06 11:12:20 -07:00
Makefile ARM: at91: remove unused duplicated filechk_offsets 2018-07-28 10:34:06 +09:00
Makefile.boot ARM: at91: Add armv7m support 2017-06-02 10:11:38 +02:00
at91rm9200.c ARM: at91: move SoC detection to its own driver 2017-03-31 20:36:10 +02:00
at91sam9.c ARM: at91: move SoC detection to its own driver 2017-03-31 20:36:10 +02:00
generic.h ARM: at91: pm: Add sama5d2 backup mode 2017-05-15 11:55:17 +02:00
pm.c ARM: Device-tree updates 2018-08-23 14:02:22 -07:00
pm.h ARM: at91: pm: Add ULP1 mode support 2018-07-17 15:08:02 +02:00
pm_data-offsets.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pm_suspend.S power: reset: at91-poweroff: switch to slow clock before shutdown 2018-09-16 12:31:48 +02:00
sama5.c ARM: at91: pm: Add sama5d2 backup mode 2017-05-15 11:55:17 +02:00
samv7.c ARM: at91: fix at91_suspend_entering_slow_clock link error 2017-06-13 11:51:11 +02:00