linux-kernel - Re: [PATCH v2] omap5-board-common: remove not physically existing vdds_1v8

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Date:   Wed, 14 Jul 2021 09:32:52 +0200
From:   "H. Nikolaus Schaller" <hns@...delico.com>
To:     Tony Lindgren <tony@...mide.com>,
        Graeme Gregory <gg@...mlogic.co.uk>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, Nishanth Menon <nm@...com>,
        peter.ujfalusi@...il.com,
        Benoît Cousson <bcousson@...libre.com>,
        Rob Herring <robh+dt@...nel.org>
Cc:     linux-omap@...r.kernel.org, linux-kernel@...r.kernel.org,
        letux-kernel@...nphoenux.org, kernel@...a-handheld.com,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v2] omap5-board-common: remove not physically existing
 vdds_1v8_main fixed-regulator

Any comments?

> Am 01.07.2021 um 16:00 schrieb H. Nikolaus Schaller <hns@...delico.com>:
> 
> This device tree include file describes a fixed-regulator
> connecting smps7_reg output (1.8V) to some 1.8V rail and
> consumers (vdds_1v8_main).
> 
> This regulator does not physically exist.
> 
> I assume it was introduced as a wrapper around smps7_reg
> to provide a speaking signal name "vdds_1v8_main" as label.
> 
> This fixed-regulator without real function was not an issue
> in driver code until
> 
>  Commit 98e48cd9283d ("regulator: core: resolve supply for boot-on/always-on regulators")
> 
> introduced a new check for regulator initialization which
> makes Palmas regulator registration fail:
> 
> [    5.407712] ldo1: supplied by vsys_cobra
> [    5.412748] ldo2: supplied by vsys_cobra
> [    5.417603] palmas-pmic 48070000.i2c:palmas@48:palmas_pmic: failed to register 48070000.i2c:palmas@48:palmas_pmic regulator
> 
> The reason is that the supply-chain of regulators is too
> long and goes from ldo3 through the virtual vdds_1v8_main
> regulator and then back to smps7. This adds a cross-dependency
> of probing Palmas regulators and the fixed-regulator which
> leads to probe deferral by the new check and is no longer
> resolved.
> 
> Since we do not control what device tree files including this
> one reference (either &vdds_1v8_main or &smps7_reg or both)
> we keep both labels for smps7 for compatibility.
> 
> Fixes: 98e48cd9283d ("regulator: core: resolve supply for boot-on/always-on regulators")
> Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
> ---
> arch/arm/boot/dts/omap5-board-common.dtsi | 9 +--------
> 1 file changed, 1 insertion(+), 8 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/omap5-board-common.dtsi b/arch/arm/boot/dts/omap5-board-common.dtsi
> index d8f13626cfd1..3a8f10231475 100644
> --- a/arch/arm/boot/dts/omap5-board-common.dtsi
> +++ b/arch/arm/boot/dts/omap5-board-common.dtsi
> @@ -30,14 +30,6 @@ vsys_cobra: fixedregulator-vsys_cobra {
> 		regulator-max-microvolt = <5000000>;
> 	};
> 
> -	vdds_1v8_main: fixedregulator-vdds_1v8_main {
> -		compatible = "regulator-fixed";
> -		regulator-name = "vdds_1v8_main";
> -		vin-supply = <&smps7_reg>;
> -		regulator-min-microvolt = <1800000>;
> -		regulator-max-microvolt = <1800000>;
> -	};
> -
> 	vmmcsd_fixed: fixedregulator-mmcsd {
> 		compatible = "regulator-fixed";
> 		regulator-name = "vmmcsd_fixed";
> @@ -487,6 +479,7 @@ smps6_reg: smps6 {
> 					regulator-boot-on;
> 				};
> 
> +				vdds_1v8_main:
> 				smps7_reg: smps7 {
> 					/* VDDS_1v8_OMAP over VDDS_1v8_MAIN */
> 					regulator-name = "smps7";
> -- 
> 2.31.1
>