linux-kernel - Re: [PATCH 3/9] regulator: core: Try full range when adjusting regulators to constraints

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Message-ID: <20160822180932.GW22076@sirena.org.uk>
Date:   Mon, 22 Aug 2016 19:09:32 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Rask Ingemann Lambertsen <ccc94453@....cybercity.dk>
Cc:     Chen-Yu Tsai <wens@...e.org>, Mark Rutland <mark.rutland@....com>,
        devicetree@...r.kernel.org, Liam Girdwood <lgirdwood@...il.com>,
        linux-kernel@...r.kernel.org, linux-sunxi@...glegroups.com,
        Rob Herring <robh+dt@...nel.org>,
        Maxime Ripard <maxime.ripard@...e-electrons.com>,
        Lee Jones <lee.jones@...aro.org>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 3/9] regulator: core: Try full range when adjusting
 regulators to constraints

On Mon, Aug 22, 2016 at 07:52:05PM +0200, Rask Ingemann Lambertsen wrote:
> On Mon, Aug 22, 2016 at 05:29:07PM +0100, Mark Brown wrote:

> > This seems like you have buggy constraints, constraints which allow
> > voltages that can't physically be satisfied don't make obvious sense.

> No, it's for cases like this (see the cubietruck4 or a80-optimus dts
> patches):

> 			reg_bldo4: bldo4 {
> 				regulator-min-microvolt = <1080000>;
> 				regulator-max-microvolt = <1320000>;
> 				regulator-name = "vcc12-hsic";
> 			};

> The regulator can do 1100000 uV, 1200000 uV and 1300000 uV, all of which
> are within the constraints, so obviously the constraints can be satisfied,
> yet the regulator core fails do so with a message like this:

Sure, but the constraints also say that you can do 1.32V which the
system is not physically capable of delivering.  That's not a good sign
for the constraints, it suggests that at least the capabilities of the
regulator have not been taken into consideration when setting up the
constraints.

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