From: Christian Lütke-Stetzkamp <christian@lkamp.de>
Date: Wed, 18 Apr 2018 15:27:28 +0000 (+0200)
Subject: staging: mt7621-mmc: Relax cpu while waiting for stable clock
X-Git-Tag: v4.18-rc1~83^2~603
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d1eade674e2edc68e5b23d26c70440a4f0cc3750;p=linux.git

staging: mt7621-mmc: Relax cpu while waiting for stable clock

Current code just busy waits with nop for clock becoming stable,
relaxing the cpu here improves readability and portability and also
removes a unnecessary difference with the mtk-sd driver.

Signed-off-by: Christian Lütke-Stetzkamp <christian@lkamp.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/mt7621-mmc/sd.c b/drivers/staging/mt7621-mmc/sd.c
index 52e6de51a91b..124a763f6049 100644
--- a/drivers/staging/mt7621-mmc/sd.c
+++ b/drivers/staging/mt7621-mmc/sd.c
@@ -618,7 +618,7 @@ static void msdc_set_mclk(struct msdc_host *host, int ddr, unsigned int hz)
 
 	/* wait clock stable */
 	while (!(sdr_read32(MSDC_CFG) & MSDC_CFG_CKSTB))
-		;
+		cpu_relax();
 
 	host->sclk = sclk;
 	host->mclk = hz;