mmc: sdio: fix runtime PM anomalies by introducing MMC_CAP_POWER_OFF_CARD

Some board/card/host configurations are not capable of powering off the
card after boot.

To support such configurations, and to allow smoother transition to
runtime PM behavior, MMC_CAP_POWER_OFF_CARD is added, so hosts need to
explicitly indicate whether it's OK to power off their cards after boot.

SDIO core will enable runtime PM for a card only if that cap is set.
As a result, the card will be powered down after boot, and will only
be powered up again when a driver is loaded (and then it's up to the
driver to decide whether power will be kept or not).

This will prevent sdio_bus_probe() failures with setups that do not
support powering off the card.

Reported-and-tested-by: Daniel Drake <dsd@laptop.org>
Reported-and-tested-by: Arnd Hannemann <arnd@arndnet.de>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 6d87f68ce4b6..30f6fad99a58 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -168,6 +168,7 @@ struct mmc_host {
                                                 /* DDR mode at 1.8V */
 #define MMC_CAP_1_2V_DDR        (1 << 12)       /* can support */
                                                 /* DDR mode at 1.2V */
+#define MMC_CAP_POWER_OFF_CARD  (1 << 13)       /* Can power off after boot */
 
         mmc_pm_flag_t           pm_caps;        /* supported pm features */