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authorPierre Ossman <drzeus@drzeus.cx>2007-09-19 18:38:50 +0200
committerPierre Ossman <drzeus@drzeus.cx>2007-09-23 21:26:06 +0200
commitf9996aee36921e8f1d499de1b2ea380855cf6d97 (patch)
tree159358eb9fa65da8997f7122fcae1c57ae948bb2
parentf75979b77fb20b01522d8fab96dfc76cc9f42420 (diff)
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>
-rw-r--r--drivers/mmc/core/core.c10
1 files changed, 9 insertions, 1 deletions
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);
}