sdhci: Add support for card-detection polling
This patch adds SDHCI_QUIRK_BROKEN_CARD_DETECTION quirk. When specified,
sdhci driver will set MMC_CAP_NEEDS_POLL MMC host capability, and won't
enable card insert/remove interrupts.
This is needed for hosts with unreliable card detection, such as FSL
eSDHC. The original eSDHC driver was tring to "debounce" card-detection
IRQs by reading present state and disabling particular interrupts. But
with this debouncing scheme I noticed that sometimes we miss card
insertion/removal events.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index a9e25c6..968d713 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -214,6 +214,8 @@
#define SDHCI_QUIRK_BROKEN_SMALL_PIO (1<<13)
/* Controller does not provide transfer-complete interrupt when not busy */
#define SDHCI_QUIRK_NO_BUSY_IRQ (1<<14)
+/* Controller has unreliable card detection */
+#define SDHCI_QUIRK_BROKEN_CARD_DETECTION (1<<15)
int irq; /* Device IRQ */
void __iomem * ioaddr; /* Mapped address */