mmc: add support for card-detection polling
Some hosts (and boards that use mmc_spi) do not use interrupts on the CD
line, so they can't trigger mmc_detect_change. We want to poll the card
and see if there was a change. 1 second poll interval seems resonable.
This patch also implements .get_cd() host operation, that could be used
by the hosts that are able to report card-detect status without need to
talk MMC.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 7ab962f..6188e19 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -51,8 +51,18 @@
struct mmc_host_ops {
void (*request)(struct mmc_host *host, struct mmc_request *req);
+ /*
+ * Avoid calling these three functions too often or in a "fast path",
+ * since underlaying controller might implement them in an expensive
+ * and/or slow way.
+ *
+ * Also note that these functions might sleep, so don't call them
+ * in the atomic contexts!
+ */
void (*set_ios)(struct mmc_host *host, struct mmc_ios *ios);
int (*get_ro)(struct mmc_host *host);
+ int (*get_cd)(struct mmc_host *host);
+
void (*enable_sdio_irq)(struct mmc_host *host, int enable);
};
@@ -94,6 +104,7 @@
#define MMC_CAP_SD_HIGHSPEED (1 << 3) /* Can do SD high-speed timing */
#define MMC_CAP_SDIO_IRQ (1 << 4) /* Can signal pending SDIO IRQs */
#define MMC_CAP_SPI (1 << 5) /* Talks only SPI protocols */
+#define MMC_CAP_NEEDS_POLL (1 << 6) /* Needs polling for card-detection */
/* host specific block data */
unsigned int max_seg_size; /* see blk_queue_max_segment_size */