From: Jisheng Zhang <jszhang@marvell.com>
Date: Sun, 4 Jan 2015 15:15:47 +0000 (+0800)
Subject: mmc: sdhci-pxav3: fix unbalanced clock issues during probe
X-Git-Tag: fixes-v4.0-rc1~141^2~42
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=62cf983ad84275f8580c807e5e596216c46773cf;p=pandora-kernel.git

mmc: sdhci-pxav3: fix unbalanced clock issues during probe

Commit 0dcaa2499b7d ("sdhci-pxav3: Fix runtime PM initialization") tries
to fix one hang issue caused by calling sdhci_add_host() on a suspended
device. The fix enables the clock twice, once by clk_prepare_enable() and
another by pm_runtime_get_sync(), meaning that the clock will never be
gated at runtime PM suspend. I observed the power consumption regression on
Marvell BG2Q SoCs.

In fact, the fix is not correct. There still be a very small window
during which a runtime suspend might somehow occur after pm_runtime_enable()
but before pm_runtime_get_sync().

This patch fixes all of the two problems by just incrementing the usage
counter before pm_runtime_enable(). It also adjust the order of disabling
runtime pm and storing the usage count in the error path to handle clock
gating properly.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Cc: <stable@vger.kernel.org> # v3.11+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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