From mboxrd@z Thu Jan 1 00:00:00 1970 From: k.kozlowski@samsung.com (Krzysztof Kozlowski) Date: Mon, 12 Jan 2015 10:23:04 +0100 Subject: [RFC 2/3] ARM: dts: Specify MSHC realistic clocks and use frequency scaling In-Reply-To: <1421054585-9032-1-git-send-email-k.kozlowski@samsung.com> References: <1421054585-9032-1-git-send-email-k.kozlowski@samsung.com> Message-ID: <1421054585-9032-3-git-send-email-k.kozlowski@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- 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