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 bdb82c1265edc8b305069903d86641d3b5303b22..b4226ba1a1b3386e2ccf9021b0601ac765966e28 100644 (file)
--- a/drivers/mmc/host/sdhci-pci-core.c
+++ b/drivers/mmc/host/sdhci-pci-core.c
@@ -677,8 +677,12 @@ 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