Re: [PATCH V2 2/3] dt-bindings: mmc: sdhci-msm: Add entries for passing load values
From: Evan Green <hidden>
Date: 2018-09-21 20:07:39
Also in:
linux-mmc, lkml
On Fri, Sep 21, 2018 at 3:32 AM Veerabhadrarao Badiganti [off-list ref] wrote:
Hi Evan, On 9/21/2018 5:45 AM, Evan Green wrote:quoted
On Wed, Sep 19, 2018 at 11:24 PM Veerabhadrarao Badiganti [off-list ref] wrote:quoted
From: Vijay Viswanath <redacted> 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 <redacted> Signed-off-by: Veerabhadrarao Badiganti <redacted> --- 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 ProjectAren'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? -EvanThe load levels here are min and max supported by the regulator. To cover all devices we do set it to max load. We can't make any assumptions on this, as peak current may vary from device to device.
Hi Veera, If it were up to me, I would just assume all devices need high power mode for BUS_ON and low power mode for BUS_OFF, and skip adding this binding until you actually came up with a device that needed lower power mode for BUS_ON, or high power mode for BUS_OFF (when would that be, anyway?) Are there any actual use cases you've seen that need different values in here? -Evan