From mboxrd@z Thu Jan 1 00:00:00 1970 From: drake@endlessm.com (Daniel Drake) Date: Mon, 21 Jul 2014 13:51:59 +0100 Subject: [PATCH v2 1/2] clk: samsung: exynos4: Enable ARMCLK down feature In-Reply-To: <1405694193-29643-1-git-send-email-k.kozlowski@samsung.com> References: <1405694193-29643-1-git-send-email-k.kozlowski@samsung.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Jul 18, 2014 at 3:36 PM, Krzysztof Kozlowski wrote: > Enable ARMCLK down feature on all Exynos4 SoCs. The frequency of > ARMCLK will be reduced upon entering idle mode (WFI or WFE). > > The feature behaves like very fast cpufreq ondemand governor. In idle > mode this reduces energy consumption on full frequency chosen by > cpufreq governor by approximately: > - Trats2: 6.5% (153 mA -> 143 mA) > - Trats: 33.0% (180 mA -> 120 mA) > - Gear1: 27.0% (180 mA -> 130 mA) > > The patch uses simillar settings as Exynos5250 (clk-exynos5250.c), > except it disables clock up feature and on Exynos4412 ARMCLK down is > enabled for all 4 cores. > > Tested on Trats board (Exynos4210), Trats2 board (Exynos4412) and > Samsung Gear 1 (Exynos4212). > > Signed-off-by: Krzysztof Kozlowski Tested on ODROID-U2, seems to be working. I don't have a way of measuring the power usage, but the system seems as stable as before. Tested-by: Daniel Drake