From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [RFC 6/6] dt-bindings: mmc: sdhci-msm: Add clk scaling dt parameters Date: Tue, 29 Oct 2019 11:36:59 -0500 Message-ID: <20191029163659.GC1057@bogus> References: <1571668177-3766-1-git-send-email-rampraka@codeaurora.org> <1571668177-3766-7-git-send-email-rampraka@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1571668177-3766-7-git-send-email-rampraka@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org To: Ram Prakash Gupta Cc: asutoshd@codeaurora.org, stummala@codeaurora.org, sayalil@codeaurora.org, vbadigan@codeaurora.org, cang@codeaurora.org, ppvk@codeaurora.org, adrian.hunter@intel.com, ulf.hansson@linaro.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org List-Id: linux-mmc@vger.kernel.org On Mon, Oct 21, 2019 at 07:59:37PM +0530, Ram Prakash Gupta wrote: > Adding clk scaling dt parameters. > > Signed-off-by: Ram Prakash Gupta > --- > Documentation/devicetree/bindings/mmc/sdhci-msm.txt | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt > index da4edb1..afaf88d 100644 > --- a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt > +++ b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt > @@ -39,6 +39,21 @@ Required properties: > "cal" - reference clock for RCLK delay calibration (optional) > "sleep" - sleep clock for RCLK delay calibration (optional) > > +Optional properties: > +- devfreq,freq-table - specifies supported frequencies for clock scaling. > + Clock scaling logic shall toggle between these frequencies based > + on card load. In case the defined frequencies are over or below > + the supported card frequencies, they will be overridden > + during card init. In case this entry is not supplied, > + the driver will construct one based on the card > + supported max and min frequencies. > + The frequencies must be ordered from lowest to highest. This should be common. Surely we already have something? > + > +- scaling-lower-bus-speed-mode - Few hosts can support DDR52 mode at the > + same lower system voltage corner as high-speed mode. In such > + cases, it is always better to put it in DDR mode which will > + improve the performance without any power impact. The description sounds like a boolean. Why the string? What are possible values? Also needs a 'qcom' vendor prefix. > + > Example: > > sdhc_1: sdhci@f9824900 { > @@ -56,6 +71,10 @@ Example: > > clocks = <&gcc GCC_SDCC1_APPS_CLK>, <&gcc GCC_SDCC1_AHB_CLK>; > clock-names = "core", "iface"; > + > + devfreq,freq-table = <50000000 200000000>; > + scaling-lower-bus-speed-mode = "DDR52" > + > }; > > sdhc_2: sdhci@f98a4900 { > -- > 1.9.1 >