mmc: Allow non-sleeping GPIO cd

This change uses the appropriate _cansleep or non-sleeping API for
reading GPIO card detect state. This allows users with GPIOs that
never sleep to avoid a warning when certain quirks are present.

The sdhci controller has an SDHCI_QUIRK_NO_CARD_NO_RESET, which
indicates that a controller will not reset properly if no card is
inserted. With this quirk enabled, mmc_get_cd_gpio is called in
several places with a spinlock held and interrupts disabled.
gpiod_get_raw_value_cansleep is not happy with this situation,
and throws out a warning.

For boards that a) use controllers that have this quirk, and b) wire
card detect up to a GPIO that doesn't sleep, this is a spurious warning.
This change silences that warning, at the cost of pushing this problem
down to users that have sleeping GPIOs and controllers with this quirk.
Signed-off-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/slot-gpio.c

@@ -79,15 +79,22 @@ EXPORT_SYMBOL(mmc_gpio_get_ro);
 int mmc_gpio_get_cd(struct mmc_host *host)
 {
 	struct mmc_gpio *ctx = host->slot.handler_priv;
+	int cansleep;
 
 	if (!ctx || !ctx->cd_gpio)
 		return -ENOSYS;
 
-	if (ctx->override_cd_active_level)
-		return !gpiod_get_raw_value_cansleep(ctx->cd_gpio) ^
-			!!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH);
+	cansleep = gpiod_cansleep(ctx->cd_gpio);
+	if (ctx->override_cd_active_level) {
+		int value = cansleep ?
+				gpiod_get_raw_value_cansleep(ctx->cd_gpio) :
+				gpiod_get_raw_value(ctx->cd_gpio);
+		return !value ^ !!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH);
+	}
 
-	return gpiod_get_value_cansleep(ctx->cd_gpio);
+	return cansleep ?
+		gpiod_get_value_cansleep(ctx->cd_gpio) :
+		gpiod_get_value(ctx->cd_gpio);
 }
 EXPORT_SYMBOL(mmc_gpio_get_cd);