From: Krzysztof Kozlowski <k.kozlowski@samsung.com>
To: Chris Ball <chris@printf.net>,
Ulf Hansson <ulf.hansson@linaro.org>,
Jaehoon Chung <jh80.chung@samsung.com>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mmc@vger.kernel.org, Kukjin Kim <kgene@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org
Cc: Kyungmin Park <kyungmin.park@samsung.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Krzysztof Kozlowski <k.kozlowski@samsung.com>
Subject: [RFC 2/3] ARM: dts: Specify MSHC realistic clocks and use frequency scaling
Date: Mon, 12 Jan 2015 10:23:04 +0100 [thread overview]
Message-ID: <1421054585-9032-3-git-send-email-k.kozlowski@samsung.com> (raw)
In-Reply-To: <1421054585-9032-1-git-send-email-k.kozlowski@samsung.com>
Lower the dw_mmc host clock from 400 MHz to 100 MHz because there are a
lot of MMC errors above 100 MHz.
Enable frequency scaling to reduce energy consumption. In idle this
reduced energy consumption by 2.6% (from 119.5 mA to 116.4 mA).
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
---
arch/arm/boot/dts/exynos4412-trats2.dts | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/exynos4412-trats2.dts b/arch/arm/boot/dts/exynos4412-trats2.dts
index 29231b452643..21f1236ae979 100644
--- a/arch/arm/boot/dts/exynos4412-trats2.dts
+++ b/arch/arm/boot/dts/exynos4412-trats2.dts
@@ -558,7 +558,9 @@
non-removable;
card-detect-delay = <200>;
vmmc-supply = <&vemmc_reg>;
- clock-frequency = <400000000>;
+ clock-frequency = <100000000>;
+ clock-freq-min-max = <400000 100000000>;
+ frequency-scaling;
samsung,dw-mshc-ciu-div = <0>;
samsung,dw-mshc-sdr-timing = <2 3>;
samsung,dw-mshc-ddr-timing = <1 2>;
--
1.9.1
next prev parent reply other threads:[~2015-01-12 9:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-12 9:23 [RFC 0/3] mmc: Add dynamic " Krzysztof Kozlowski
2015-01-12 9:23 ` [RFC 1/3] " Krzysztof Kozlowski
2015-01-12 9:23 ` Krzysztof Kozlowski [this message]
2015-01-12 9:23 ` [RFC 3/3] ARM: dts: Use frequency scaling for MSHC Krzysztof Kozlowski
2015-01-15 8:20 ` [RFC 0/3] mmc: Add dynamic frequency scaling Ulf Hansson
2015-01-15 9:20 ` Krzysztof Kozlowski
2015-01-15 10:04 ` Ulf Hansson
2015-01-17 23:52 ` Mike Turquette
2015-01-15 15:25 ` Tomeu Vizoso
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