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mmc: increase power up delay 

Increase delay for power up in order to support some slower boards.

Also add some comments about why the delays are there.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
This commit is contained in:
Pierre Ossman 2007-09-19 18:38:50 +02:00
parent f75979b77f
commit f9996aee36
1 changed files with 9 additions and 1 deletions
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10
drivers/mmc/core/core.c
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@ -460,12 +460,20 @@ static void mmc_power_up(struct mmc_host *host)
host->ios.timing = MMC_TIMING_LEGACY;
mmc_set_ios(host);
mmc_delay(1);
/*
* This delay should be sufficient to allow the power supply
* to reach the minimum voltage.
*/
mmc_delay(2);
host->ios.clock = host->f_min;
host->ios.power_mode = MMC_POWER_ON;
mmc_set_ios(host);
/*
* This delay must be at least 74 clock sizes, or 1 ms, or the
* time required to reach a stable voltage.
*/
mmc_delay(2);
}