mmc: enable MMC/SD/SDIO device to suspend/resume asynchronously

Now, PM core supports asynchronous suspend/resume mode for devices during system suspend/resume, and the power state transition of one device may be completed in separate kernel thread. PM core ensures all power state transition dependency between devices. This patch enables MMC/SD/SDIO card and SDIO function devices to suspend/resume asynchronously. This will take advantage of multicore and improve system suspend/resume speed. After applying this patch and enabling all SDIO function's child devices to suspend/resume asynchronously on ASUS T100TA, the system suspend-to-idle time is reduced from 1645ms to 1108ms, and the system resume time is reduced from 940ms to 918ms.

Signed-off-by Zhonghui Fu <[email protected]>

---
 drivers/mmc/core/bus.c      |    2 ++
 drivers/mmc/core/sdio_bus.c |    1 +
 2 files changed, 3 insertions(+), 0 deletions(-)

drivers/mmc/core/bus.c +2 -0

index 972ff84..4bc48f1 100644
@@ -349,6 +349,8 @@ int mmc_add_card(struct mmc_card *card)
 
        card->dev.of_node = mmc_of_find_child_device(card->host, 0);
 
+       device_enable_async_suspend(&card->dev);
+
        ret = device_add(&card->dev);
        if (ret)
                return ret;

drivers/mmc/core/sdio_bus.c +1 -2

index 7e327a6..86f5b32 100644
@@ -322,6 +322,7 @@ int sdio_add_func(struct sdio_func *func)
 
        sdio_set_of_node(func);
        sdio_acpi_set_handle(func);
+       device_enable_async_suspend(&func->dev);
        ret = device_add(&func->dev);
        if (ret == 0)
                sdio_func_set_present(func);
-- 1.7.1
 
--

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