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>

diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
index 1f0bd723f01124dd3e9b28b8afa3d000603d64d9..13a84b9309e064100caa7f1ec258907ef1de50e3 100644 (file)
--- a/drivers/mmc/host/sdhci-pci-core.c
+++ b/drivers/mmc/host/sdhci-pci-core.c
@@ -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