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Commit 3ec1ed2a authored by Guoping Yu's avatar Guoping Yu Committed by Gerrit - the friendly Code Review server
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mmc: core: increase delay between power-up and power-on 



Add a capability to selectively increase the delay between
power_up and power_on. This delay was arrived at after performing
a series of experiments to find the minimum value. It is required
in some scenarios to avoid command timeouts during resume.

Change-Id: I857e740aa20a33e08515d054e5c9bf128db229c6
Signed-off-by: default avatarGuoping Yu <guopingy@codeaurora.org>
parent c5bc590f

drivers/mmc/core/core.c

+4 −1
Original line number Diff line number Diff line
@@ -2085,6 +2085,9 @@ void mmc_power_up(struct mmc_host *host) 
	 * This delay should be sufficient to allow the power supply

	 * to reach the minimum voltage.

	 */

	if (host->caps2 & MMC_CAP2_VDD_MORE_POWER_UP_TIME)

		mmc_delay(150);

	else

		mmc_delay(10);



	host->ios.clock = host->f_init;

include/linux/mmc/host.h

+2 −0
Original line number Diff line number Diff line
@@ -330,6 +330,8 @@ struct mmc_host { 
#define MMC_CAP2_HS400		(MMC_CAP2_HS400_1_8V | \

				 MMC_CAP2_HS400_1_2V)

#define MMC_CAP2_NONHOTPLUG	(1 << 25)	/*Don't support hotplug*/

/*Vdd need more power up time*/

#define MMC_CAP2_VDD_MORE_POWER_UP_TIME	(1 << 26)

	mmc_pm_flag_t		pm_caps;	/* supported pm features */



	int			clk_requests;	/* internal reference counter */