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[2/4] mmci: adjust calculation of f_min

Message ID 1309247853-17143-1-git-send-email-linus.walleij@stericsson.com
State Accepted
Headers show

Commit Message

Linus Walleij June 28, 2011, 7:57 a.m. UTC 
From: Ulf Hansson <ulf.hansson@stericsson.com>

For the st_clkdiv variant f_min is too low for practical cases,
there is a heuristic calculation that appear to set the min
frequency to mclk rounded up with 512, for our practical use
cases dividing by 257 gives a reasonable floor value on the
ST Micro version of the clock divider.

Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Reviewed-by: Sebastian Rasmussen <sebastian.rasmussen@stericsson.com>
[Use DIV_ROUND_UP to clarify elder code]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/mmc/host/mmci.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
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Patch

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index fe14072..c73d054 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -1063,7 +1063,10 @@  static int __devinit mmci_probe(struct amba_device *dev,
 	}
 
 	mmc->ops = &mmci_ops;
-	mmc->f_min = (host->mclk + 511) / 512;
+	if (variant->st_clkdiv)
+		mmc->f_min = host->mclk / 257;
+	else
+		mmc->f_min = DIV_ROUND_UP(host->mclk, 512);
 	/*
 	 * If the platform data supplies a maximum operating
 	 * frequency, this takes precedence. Else, we fall back