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[PATCHv5,03/20] OMAP: McBSP: Use appropriate value for startup delay

Message ID 1250518143-13336-1-git-send-email-eduardo.valentin@nokia.com (mailing list archive)
State Awaiting Upstream, archived
Headers show

Commit Message

Eduardo Valentin Aug. 17, 2009, 2:09 p.m. UTC 
From: Eduardo Valentin <eduardo.valentin@nokia.com>

Increasing startup delay value as worst case:
 CLKSRG*2 = 8000khz: (1/8000) * 2 * 2 usec

Although, 100us may give enough time for two CLKSRG,
due to some unknown PM related, clock gating etc. reason,
this patch increases it to 500us.

Signed-off-by: Eduardo Valentin <eduardo.valentin@nokia.com>
---
 arch/arm/plat-omap/mcbsp.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)
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Patch

diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
index 0aa2524..e9dd703 100644
--- a/arch/arm/plat-omap/mcbsp.c
+++ b/arch/arm/plat-omap/mcbsp.c
@@ -365,7 +365,13 @@  void omap_mcbsp_start(unsigned int id, int tx, int rx)
 	w = OMAP_MCBSP_READ(io_base, SPCR1);
 	OMAP_MCBSP_WRITE(io_base, SPCR1, w | (rx & 1));
 
-	udelay(100);
+	/*
+	 * Worst case: CLKSRG*2 = 8000khz: (1/8000) * 2 * 2 usec
+	 * REVISIT: 100us may give enough time for two CLKSRG, however
+	 * due to some unknown PM related, clock gating etc. reason it
+	 * is now at 500us.
+	 */
+	udelay(500);
 
 	if (idle) {
 		/* Start frame sync */