IMX6Q EMMC sleep mode for Android 4.4 BSP

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IMX6Q EMMC sleep mode for Android 4.4 BSP

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changyuheng
Contributor II

Hello All:

As title, Because I want to decrease power consumption when OS entering sleep mode,

my EMMC vendor is Kinston 4G size, their EMMC support sleep mode.

I trying to modify source code as following:

static const struct esdhc_platform_data mx6q_sabresd_sd4_data __initconst = {

    .always_present = 1,

    .keep_power_at_suspend = 0,

    .support_8bit = 1,

    .delay_line = 0,

    .cd_type = ESDHC_CD_PERMANENT,

};

but the power consumption still no decrease.

so what can I do to decrease EMMC suspend power consumption?

Thanks a lot!

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igorpadykov
NXP TechSupport
NXP TechSupport

Hi Publlic

".keep_power_at_suspend" structure host->mmc->pm_caps |= MMC_PM_KEEP_POWER

is used for SDIO cards, not eMMC.

SDIO MMC keep power – enable the SDIO to avoid re enumeration after

resuming from suspend mode, since the assumption is that the SDIO

continue to be in Active mode during Hosts Suspend mode.

Linux/Documentation/devicetree/bindings/mmc/mmc.txt - Linux Cross Reference - Free Electrons

Best regards

igor

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changyuheng
Contributor II

Thanks .

After I traced Android 4.4 BSP kernel source, eMMC sleep mode was defined in

kernel_imx\drivers\mmc\core\mmc.c, and I don't know why eMMC was in mmc_ops_unsafe mode.

I trying to set eMMC for sleep mode for mmc.c, but eMMC cause OS crash when Android OS enter suspend mode, eMMC only support suspend mode, not for sleep mode.

how to fix this issue? thanks.

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igorpadykov
NXP TechSupport
NXP TechSupport

I think you can ask EMMC vendor Kinston

what correct sequence should be for sleep mode.

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