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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>
This commit is contained in:
Anton Vorontsov 2008-06-17 18:17:15 +04:00 committed by Pierre Ossman
parent 150a55683b
commit 28f52482b4
2 changed files with 20 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/mmc/core/core.c
View File

@ -638,6 +638,9 @@ void mmc_rescan(struct work_struct *work)
*/
mmc_bus_put(host);
if (host->ops->get_cd && host->ops->get_cd(host) == 0)
goto out;
mmc_claim_host(host);
mmc_power_up(host);
@ -652,7 +655,7 @@ void mmc_rescan(struct work_struct *work)
if (!err) {
if (mmc_attach_sdio(host, ocr))
mmc_power_off(host);
return;
goto out;
}
/*
@ -662,7 +665,7 @@ void mmc_rescan(struct work_struct *work)
if (!err) {
if (mmc_attach_sd(host, ocr))
mmc_power_off(host);
return;
goto out;
}
/*
@ -672,7 +675,7 @@ void mmc_rescan(struct work_struct *work)
if (!err) {
if (mmc_attach_mmc(host, ocr))
mmc_power_off(host);
return;
goto out;
}
mmc_release_host(host);
@ -683,6 +686,9 @@ void mmc_rescan(struct work_struct *work)
mmc_bus_put(host);
}
out:
if (host->caps & MMC_CAP_NEEDS_POLL)
mmc_schedule_delayed_work(&host->detect, HZ);
}
void mmc_start_host(struct mmc_host *host)

11
include/linux/mmc/host.h
View File

@ -51,8 +51,18 @@ struct mmc_ios {
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 @@ struct mmc_host {
#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 */