From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Collins Subject: Re: [PATCH] regulator: core: Allow for regulators that can't be read at bootup Date: Wed, 16 May 2018 15:47:22 -0700 Message-ID: <4547e1cb-a39c-decd-9384-4e2c6d28f64d@codeaurora.org> References: <20180515220717.254950-1-dianders@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180515220717.254950-1-dianders@chromium.org> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Douglas Anderson , broonie@kernel.org Cc: mka@chromium.org, Liam Girdwood , linux-kernel@vger.kernel.org, "linux-arm-msm@vger.kernel.org" List-Id: linux-arm-msm@vger.kernel.org On 05/15/2018 03:07 PM, Douglas Anderson wrote: > As discussed in the patches to try to support the RPMh regulators [1], > the fact that regulators are write-only means that its driver's > get_voltage_sel() should return an error code if it's called before > any calls to set_voltage_sel(). This causes problems in > machine_constraints_voltage() when trying to apply the constraints. This problem specifically arises in the latest RPMh regulator patch [1] if regulator-min-microvolt and regulator-max-microvolt are specified for a VRM managed RPMh regulator device but the qcom,regulator-initial-microvolt property is not provided. Therefore, listing qcom,regulator-initial-microvolt is a way to avoid regulator registration issues. > In this patch I propose the error code -ENOTRECOVERABLE. In errno.h > this error is described as "State not recoverable". I'm fine with this constant. Hopefully Mark is as well. > If this patch is accepted then we'll need to update the latest RPMh > regulator patch to return it. The current patch returns -EINVAL which > means that the regulator always fails. I'll make this modification if needed. Take care, David [1] https://lkml.org/lkml/2018/5/11/703 -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project