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erickshepherdNIstorulf
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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: Erick Shepherd <erick.shepherd@ni.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Link: https://lore.kernel.org/r/20250314195021.1588090-1-erick.shepherd@ni.com Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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drivers/mmc/host/sdhci-pci-core.c

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -610,8 +610,12 @@ static void sdhci_intel_set_power(struct sdhci_host *host, unsigned char mode,
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sdhci_set_power(host, mode, vdd);
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if (mode == MMC_POWER_OFF)
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if (mode == MMC_POWER_OFF) {
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if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_APL_SD ||
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slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BYT_SD)
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usleep_range(15000, 17500);
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return;
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}
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/*
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* Bus power might not enable after D3 -> D0 transition due to the

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