Eric Lee / smarc-uboot

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Commit 3747a3f010b2b1442dec3e871c69788b6017aaae

Authored by Domen Puncer
Committed by Stefan Roese
1 parent e673226ff9
Exists in master and in 55 other branches 8qm-imx_v2020.04_5.4.70_2.3.0, emb_lf_v2022.04, emb_lf_v2023.04, imx_v2015.04_4.1.15_1.0.0_ga, pitx_8mp_lf_v2020.04, smarc-8m-android-10.0.0_2.6.0, smarc-8m-android-11.0.0_2.0.0, smarc-8mp-android-11.0.0_2.0.0, smarc-emmc-imx_v2014.04_3.10.53_1.1.0_ga, smarc-emmc-imx_v2014.04_3.14.28_1.0.0_ga, smarc-imx-l5.0.0_1.0.0-ga, smarc-imx6_v2018.03_4.14.98_2.0.0_ga, smarc-imx7_v2017.03_4.9.11_1.0.0_ga, smarc-imx7_v2018.03_4.14.98_2.0.0_ga, smarc-imx_v2014.04_3.14.28_1.0.0_ga, smarc-imx_v2015.04_4.1.15_1.0.0_ga, smarc-imx_v2017.03_4.9.11_1.0.0_ga, smarc-imx_v2017.03_4.9.88_2.0.0_ga, smarc-imx_v2017.03_o8.1.0_1.3.0_8m, smarc-imx_v2018.03_4.14.78_1.0.0_ga, smarc-m6.0.1_2.1.0-ga, smarc-n7.1.2_2.0.0-ga, smarc-rel_imx_4.1.15_2.0.0_ga, smarc_8m-imx_v2018.03_4.14.98_2.0.0_ga, smarc_8m-imx_v2019.04_4.19.35_1.1.0, smarc_8m_00d0-imx_v2018.03_4.14.98_2.0.0_ga, smarc_8mm-imx_v2018.03_4.14.98_2.0.0_ga, smarc_8mm-imx_v2019.04_4.19.35_1.1.0, smarc_8mm-imx_v2020.04_5.4.24_2.1.0, smarc_8mp_lf_v2020.04, smarc_8mq-imx_v2020.04_5.4.24_2.1.0, smarc_8mq_lf_v2020.04, ti-u-boot-2015.07, u-boot-2013.01.y, v2013.10, v2013.10-smarct33, v2013.10-smartmen, v2014.01, v2014.04, v2014.04-smarct33, v2014.04-smarct33-emmc, v2014.04-smartmen, v2014.07, v2014.07-smarct33, v2014.07-smartmen, v2015.07-smarct33, v2015.07-smarct33-emmc, v2015.07-smarct4x, v2016.05-dlt, v2016.05-smarct3x, v2016.05-smarct3x-emmc, v2016.05-smarct4x, v2017.01-smarct3x, v2017.01-smarct3x-emmc, v2017.01-smarct4x

[PATCH] icecube/lite5200b: document wakeup from low-power support 

Signed-off-by: Domen Puncer <domen.puncer@telargo.com>

Showing 1 changed file with 22 additions and 0 deletions Side-by-side Diff

doc/README.Lite5200B_low_power
Diff comments   View file @ 3747a3f
  1 +Lite5200B wakeup from low-power mode (CONFIG_LITE5200B_PM)
  2 +----------------------------------------------------------
  3 +
  4 +Low-power mode as described in Lite5200B User's Manual, means that
  5 +with support of MC68HLC908QT1 microcontroller (refered to as QT),
  6 +everything but the SDRAM can be powered down. This brings
  7 +maximum power saving, while one can still restore previous state
  8 +quickly.
  9 +
  10 +Quick overview where U-Boot comes into the picture:
  11 +- OS saves device states
  12 +- OS saves wakeup handler address to physical 0x0, puts SDRAM into
  13 + self-refresh and signals to QT, it should power down the board
  14 +- / board is sleeping here /
  15 +- someone presses SW4 (connected to QT)
  16 +- U-Boot checks PSC2_4 pin, if QT drives it down, then we woke up,
  17 + so get SDRAM out of self-refresh and transfer control to OS
  18 + wakeup handler
  19 +- OS restores device states
  20 +
  21 +This was tested on Linux with USB and Ethernet in use. Adding
  22 +support for other devices is an OS issue.