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From:   Evan Green <evgreen@chromium.org>
Date:   Thu, 20 Sep 2018 17:15:51 -0700
Message-ID: <CAE=gft6w_iV+vm=u=ZKNvDLVTHcAO+AR0A9Yg9etTHW8bJy05w@mail.gmail.com>
Subject: Re: [PATCH V2 2/3] dt-bindings: mmc: sdhci-msm: Add entries for
 passing load values
To:     vbadigan@codeaurora.org
Cc:     adrian.hunter@intel.com, Ulf Hansson <ulf.hansson@linaro.org>,
        robh+dt@kernel.org, linux-mmc@vger.kernel.org,
        asutoshd@codeaurora.org, riteshh@codeaurora.org,
        stummala@codeaurora.org, sayali <sayalil@codeaurora.org>,
        Doug Anderson <dianders@google.com>, vviswana@codeaurora.org,
        mark.rutland@arm.com, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Wed, Sep 19, 2018 at 11:24 PM Veerabhadrarao Badiganti
<vbadigan@codeaurora.org> wrote:
>
> From: Vijay Viswanath <vviswana@codeaurora.org>
>
> The load a particular sdhc controller should request from a regulator
> is device specific and hence each device should individually vote for
> the required load.
>
> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
> ---
>  Documentation/devicetree/bindings/mmc/sdhci-msm.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
> index 502b3b8..3720385 100644
> --- a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
> +++ b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
> @@ -26,6 +26,11 @@ Required properties:
>         "cal"   - reference clock for RCLK delay calibration (optional)
>         "sleep" - sleep clock for RCLK delay calibration (optional)
>
> +Optional properties:
> +- qcom,<supply>-current-level-microamp - specifies load levels for supply during BUS_ON and
> +                                       BUS_OFF states in power irq. Should be specified in
> +                                       pairs (lpm, hpm), for BUS_OFF and BUS_ON respectively.
> +                                       Units uA.
>  Example:
>
>         sdhc_1: sdhci@f9824900 {
> @@ -37,6 +42,7 @@ Example:
>
>                 vmmc-supply = <&pm8941_l20>;
>                 vqmmc-supply = <&pm8941_s3>;
> +               qcom,vqmmc-current-level-microamp = <200 22000>;
>
>                 pinctrl-names = "default";
>                 pinctrl-0 = <&sdc1_clk &sdc1_cmd &sdc1_data>;
> --
> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc., is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
>

Aren't the regulator load levels pretty coarse? Would it be safe to
say that pretty much all sd/mmc devices need the high powered mode, or
are there really some devices that can get by with LPM all the time?
-Evan