From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753794AbbLJCV0 (ORCPT ); Wed, 9 Dec 2015 21:21:26 -0500 Received: from mailout4.w1.samsung.com ([210.118.77.14]:19829 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751875AbbLJCVX (ORCPT ); Wed, 9 Dec 2015 21:21:23 -0500 MIME-version: 1.0 Content-type: text/plain; charset=utf-8 X-AuditID: cbfec7f4-f79026d00000418a-c5-5668e1a048c8 Content-transfer-encoding: 8BIT Subject: Re: [PATCH v2 03/19] ARM: dts: Add DMC bus node for Exynos3250 To: Chanwoo Choi , myungjoo.ham@samsung.com, kgene@kernel.org References: <1449634091-1842-1-git-send-email-cw00.choi@samsung.com> <1449634091-1842-4-git-send-email-cw00.choi@samsung.com> <5668CADE.8090706@samsung.com> <5668D0B6.1030902@samsung.com> <5668D34B.1010602@samsung.com> <5668DCDB.8020609@samsung.com> <5668DDBF.2070305@samsung.com> <5668E0D6.7000200@samsung.com> Cc: kyungmin.park@samsung.com, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, linux@arm.linux.org.uk, tjakobi@math.uni-bielefeld.de, linux.amoon@gmail.com, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-samsung-soc@vger.kernel.org, devicetree@vger.kernel.org From: Krzysztof Kozlowski Message-id: <5668E199.7010001@samsung.com> Date: Thu, 10 Dec 2015 11:21:13 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 In-reply-to: <5668E0D6.7000200@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprNIsWRmVeSWpSXmKPExsVy+t/xq7oLHmaEGezrZLG4/uU5q8X8I+dY LfrfLGS1OPdqJaPF6xeGFv2PXzNbnG16w25xedccNovPvUcYLWac38dksW7jLXaL25d5LZZe v8hkcbtxBZvFhOlrWSxa9x5ht2hb/YHVQdBjzbw1jB4tzT1sHpf7epk8ds66y+6xcvkXNo9N qzrZPP4dY/fo27KK0ePzJrkAzigum5TUnMyy1CJ9uwSujNOH5rMUfJevaDrxj62B8aJkFyMn h4SAiUTn76tsELaYxIV764FsLg4hgaWMElcevmEHSfAKCEr8mHyPpYuRg4NZQF7iyKVsCFNd YsqUXIjyp4wSS24dApsjLOAucezXcSYQW0QgTGL2jB/MEEX7mSTePW5lAnGYBe4ySVx8/wSs g03AWGLz8iVsIFN5BbQkbndFgoRZBFQlfq5fB7ZXVCBCYtGOTJAwp4C2REfLV9YJjAKzkFw3 C+G6WQjXLWBkXsUomlqaXFCclJ5rqFecmFtcmpeul5yfu4kREmVfdjAuPmZ1iFGAg1GJh/eC S3qYEGtiWXFl7iFGCQ5mJRHeJw8ywoR4UxIrq1KL8uOLSnNSiw8xSnOwKInzzt31PkRIID2x JDU7NbUgtQgmy8TBKdXA6CCUN7uhOVTQIuB+bUvWVUNxReG1wYZHd7gIpT1+bWn3Ma3oZWyv i0aFz7zYvYnHRG3dPyUHP/FoU69pCVuiJ2ulu/gHQ4zj09VPEzqv9WeeXinA86Zsl/Ckgs0b boQsryi2unu17Xr4YuNimQbZiRf3rGA99M3kgc3PNNMpL94KHpuurKuvxFKckWioxVxUnAgA Ks4jJK4CAAA= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10.12.2015 11:17, Chanwoo Choi wrote: > On 2015년 12월 10일 11:04, Krzysztof Kozlowski wrote: >> On 10.12.2015 11:00, Chanwoo Choi wrote: >>> On 2015년 12월 10일 10:20, Krzysztof Kozlowski wrote: >>>> On 10.12.2015 10:09, Chanwoo Choi wrote: >>>>> On 2015년 12월 10일 09:44, Krzysztof Kozlowski wrote: >>>>>> On 09.12.2015 13:07, Chanwoo Choi wrote: >>>>>>> This patch adds the DMC (Dynamic Memory Controller) bus node for Exynos3250 SoC. >>>>>>> The DMC is an AMBA AXI-compliant slave to interface external JEDEC standard >>>>>>> SDRAM devices. The bus includes the OPP tables and the source clock for DMC >>>>>>> block. >>>>>>> >>>>>>> Following list specifies the detailed relation between the clock and DMC block: >>>>>>> - The source clock of DMC block : div_dmc >>>>>>> >>>>>>> Signed-off-by: Chanwoo Choi >>>>>>> --- >>>>>>> arch/arm/boot/dts/exynos3250.dtsi | 34 ++++++++++++++++++++++++++++++++++ >>>>>>> 1 file changed, 34 insertions(+) >>>>>>> >>>>>>> diff --git a/arch/arm/boot/dts/exynos3250.dtsi b/arch/arm/boot/dts/exynos3250.dtsi >>>>>>> index 2f30d632f1cc..7214c5e42150 100644 >>>>>>> --- a/arch/arm/boot/dts/exynos3250.dtsi >>>>>>> +++ b/arch/arm/boot/dts/exynos3250.dtsi >>>>>>> @@ -687,6 +687,40 @@ >>>>>>> clock-names = "ppmu"; >>>>>>> status = "disabled"; >>>>>>> }; >>>>>>> + >>>>>>> + bus_dmc: bus_dmc { >>>>>>> + compatible = "samsung,exynos-bus"; >>>>>>> + clocks = <&cmu_dmc CLK_DIV_DMC>; >>>>>>> + clock-names = "bus"; >>>>>>> + operating-points-v2 = <&bus_dmc_opp_table>; >>>>>>> + status = "disabled"; >>>>>>> + }; >>>>>>> + >>>>>>> + bus_dmc_opp_table: opp_table1 { >>>>>> >>>>>> This is the firsy opp_table, right? So: >>>>>> s/opp_table1/opp_table0/ >>>>> >>>>> Right. It is first opp_table in exynos3250.dtsi. >>>>> But, I'm considering the OPP table of CPU freqeuncy as opp_table0. >>>>> So, I have the plan that support the operation-points-v2 for Exynos3250 CPU. >>>> >>>> Ok >>>> >>>>> >>>>>> >>>>>>> + compatible = "operating-points-v2"; >>>>>>> + opp-shared; >>>>>>> + >>>>>>> + opp00 { >>>>>>> + opp-hz = /bits/ 64 <50000000>; >>>>>>> + opp-microvolt = <800000>; >>>>>>> + }; >>>>>>> + opp01 { >>>>>>> + opp-hz = /bits/ 64 <100000000>; >>>>>>> + opp-microvolt = <800000>; >>>>>>> + }; >>>>>>> + opp02 { >>>>>>> + opp-hz = /bits/ 64 <134000000>; >>>>>>> + opp-microvolt = <800000>; >>>>>> >>>>>> Why 134, not 133 MHz? >>>>> >>>>> When I used the 133000000, the source clock is changed to 100Mhz instead of 133MHz. >>>>> I add following test result on exynos3250-rinato board. >>>>> >>>>> Case1. >>>>> When I use the 134 MHz, the source clock is changed to 133MHz >>>>> : exynos-bus soc:bus_dmc: old_freq(200000000) -> new_freq (134000000) (real: 133333334) >>>>> >>>>> Case2. >>>>> When I use the 133 MHz, the source clock is changed to 100MHz >>>>> : exynos-bus soc:bus_dmc: old_freq(200000000) -> new_freq (133000000) (real: 100000000) >>>> >>>> Now I remember that issue. You could use here directly 133333334 but >>>> that also would look a little bit weird... so 134 is ok for me. Could >>>> just add a comment that desired frequency is actually "133 MHz"? >>> >>> Do you prefer among following example? >>> >>> Example1. >>> opp02 { >>> /* The desired frequency is 133MHz because >>> * clock change has the dependency on clock driver. >>> * When set rate as 134MHz, the clock driver would >>> * change the 133MHz actually instead of 134MHz. >>> */ >>> opp-hz = /bits/ 64 <134000000>; >>> opp-microvolt = <800000>; >>> }; >>> >>> Example2. >>> opp02 { >>> opp-hz = /bits/ 64 <133333334>; >>> opp-microvolt = <800000>; >>> }; >> >> I would prefer the second one (133333334) but I don't have strong >> feelings about it. > > If you ok, I want to maintain the original approach as following: > > opp02 { > opp-hz = /bits/ 64 <134000000>; > opp-microvolt = <800000>; > }; OK Best regards, Krzysztof