Commit 31e75ed9 authored by Erick Shepherd's avatar Erick Shepherd Committed by Ulf Hansson
Browse files

mmc: host: Wait for Vdd to settle on card power off 



The SD spec version 6.0 section 6.4.1.5 requires that Vdd must be
lowered to less than 0.5V for a minimum of 1 ms when powering off a
card. Increase wait to 15 ms so that voltage has time to drain down
to 0.5V and cards can power off correctly. Issues with voltage drain
time were only observed on Apollo Lake and Bay Trail host controllers
so this fix is limited to those devices.

Signed-off-by: default avatarErick Shepherd <erick.shepherd@ni.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20250314195021.1588090-1-erick.shepherd@ni.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent f4dfef81

drivers/mmc/host/sdhci-pci-core.c

+5 −1
Original line number Diff line number Diff line
@@ -610,8 +610,12 @@ static void sdhci_intel_set_power(struct sdhci_host *host, unsigned char mode, 


	sdhci_set_power(host, mode, vdd);



	if (mode == MMC_POWER_OFF)

	if (mode == MMC_POWER_OFF) {

		if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_APL_SD ||

		    slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BYT_SD)

			usleep_range(15000, 17500);

		return;

	}



	/*

	 * Bus power might not enable after D3 -> D0 transition due to the