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

[ Upstream commit 31e75ed964582257f59156ce6a42860e1ae4cc39 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
index 6b351810a301c935e981ed5784a3676b54e0b66c..dbfe0a5324eaf07eec0ee1889bc6f65cfa628325 100644 (file)
--- a/drivers/mmc/host/sdhci-pci-core.c
+++ b/drivers/mmc/host/sdhci-pci-core.c
@@ -608,8 +608,12 @@ 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