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 our wait to 15 ms so that voltage has time to drain down
to 0.5V and cards can power off correctly.

Signed-off-by: Erick Shepherd <[email protected]>

Author: erickshepherdNI

drivers/mmc/host/sdhci.c

@@ -2147,6 +2147,9 @@ EXPORT_SYMBOL_GPL(sdhci_set_power_noreg);
 void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
 		     unsigned short vdd)
 {
+	if (mode == MMC_POWER_OFF)
+		usleep_range(15000, 17500);
+
 	if (IS_ERR(host->mmc->supply.vmmc))
 		sdhci_set_power_noreg(host, mode, vdd);
 	else