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From: dianders@chromium.org (Doug Anderson)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] mmc: dw_mmc: rockchip: Don't recalc the clock when it goes off
Date: Tue, 14 Oct 2014 09:39:12 -0700	[thread overview]
Message-ID: <1413304752-7823-1-git-send-email-dianders@chromium.org> (raw)

The "set_ios" function is called with a clock of 0 when the clock is
turning off.  There's no reason to go through all the extra Rockchip
logic (whose goal is to make sure DIV is 0 or 1) in that case.  The
Rockchip logic happened to work because the CCF will pick the lowest
possible rate when you ask it for a clock of 0, but it's silly to go
through all the remuxing and adjusting for no reason.

Signed-off-by: Doug Anderson <dianders@chromium.org>
---
 drivers/mmc/host/dw_mmc-rockchip.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mmc/host/dw_mmc-rockchip.c b/drivers/mmc/host/dw_mmc-rockchip.c
index f0c2cb1..bbb4ec3 100644
--- a/drivers/mmc/host/dw_mmc-rockchip.c
+++ b/drivers/mmc/host/dw_mmc-rockchip.c
@@ -37,6 +37,9 @@ static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
 	unsigned int cclkin;
 	u32 bus_hz;
 
+	if (ios->clock == 0)
+		return;
+
 	/*
 	 * cclkin: source clock of mmc controller
 	 * bus_hz: card interface clock generated by CLKGEN
-- 
2.1.0.rc2.206.gedb03e5

             reply	other threads:[~2014-10-14 16:39 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-14 16:39 Doug Anderson [this message]
2014-10-16  2:21 ` [PATCH] mmc: dw_mmc: rockchip: Don't recalc the clock when it goes off Jaehoon Chung
2014-10-27 14:18 ` Ulf Hansson

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