From mboxrd@z Thu Jan 1 00:00:00 1970 From: collinsd@codeaurora.org (David Collins) Date: Tue, 10 Jul 2018 15:32:11 -0700 Subject: [PATCH 2/3] arm64: dts: qcom: sdm845-mtp: Add RPMh VRM/XOB regulators In-Reply-To: <20180710220202.116404-3-dianders@chromium.org> References: <20180710220202.116404-1-dianders@chromium.org> <20180710220202.116404-3-dianders@chromium.org> Message-ID: <0d334051-2ba5-075d-df8c-affe3e617e8d@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello Doug, On 07/10/2018 03:02 PM, Douglas Anderson wrote: ... > + vdd-s1-supply = <&vph_pwr>; > + vdd-s2-supply = <&vph_pwr>; > + vdd-s3-supply = <&vph_pwr>; > + vdd-s4-supply = <&vph_pwr>; > + vdd-s5-supply = <&vph_pwr>; > + vdd-s6-supply = <&vph_pwr>; > + vdd-s7-supply = <&vph_pwr>; > + vdd-s8-supply = <&vph_pwr>; > + vdd-s9-supply = <&vph_pwr>; > + vdd-s10-supply = <&vph_pwr>; > + vdd-s11-supply = <&vph_pwr>; > + vdd-s12-supply = <&vph_pwr>; > + vdd-s13-supply = <&vph_pwr>; > + vdd-l1-l27-supply = <&vreg_s7a_1p025>; > + vdd-l2-l8-l17-supply = <&vreg_s3a_1p35>; > + vdd-l3-l11-supply = <&vreg_s7a_1p025>; > + vdd-l4-l5-supply = <&vreg_s7a_1p025>; > + vdd-l6-supply = <&vph_pwr>; > + vdd-l7-l12-l14-l15-supply = <&vreg_s5a_2p04>; > + vdd-l9-supply = <&vreg_bob>; > + vdd-l10-l23-l25-supply = <&vreg_bob>; > + vdd-l13-l19-l21-supply = <&vreg_bob>; > + vdd-l16-l28-supply = <&vreg_bob>; > + vdd-l18-l22-supply = <&vreg_bob>; > + vdd-l20-l24-supply = <&vreg_bob>; > + vdd-l26-supply = <&vreg_s3a_1p35>; > + vin-lvs-1-2-supply = <&vreg_s4a_1p8>; I would suggest not specifying any of these regulator parent supplies in device tree. RPMh will be enforcing all regulator parent-child dependencies. Therefore, handling the dependencies in Linux is redundant. It will result in additional RPMh requests as well as more time spent in regulator framework calls. Overall, it will lead to slightly lower performance. Note that while specifying the parent supplies results in less efficient runtime behavior, it is not technically wrong so you could keep them in place if you prefer. Take care, David