From f9996aee36921e8f1d499de1b2ea380855cf6d97 Mon Sep 17 00:00:00 2001 From: Pierre Ossman Date: Wed, 19 Sep 2007 18:38:50 +0200 Subject: 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 --- drivers/mmc/core/core.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'drivers/mmc/core') diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 3bebd3b55dc..bffcaf8df35 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -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); } -- cgit v1.2.3