linux-kernel - Re: [PATCH] arm: dts: fix rk3066a based boards vdd

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Message-ID: <20160922164752.GP7994@sirena.org.uk>
Date:   Thu, 22 Sep 2016 17:47:52 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Boris Brezillon <boris.brezillon@...e-electrons.com>
Cc:     Doug Anderson <dianders@...omium.org>,
        Heiko Stuebner <heiko@...ech.de>,
        Andy Yan <andy.yan@...k-chips.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] arm: dts: fix rk3066a based boards vdd_log voltage
 initialization

On Thu, Sep 22, 2016 at 05:12:17PM +0200, Boris Brezillon wrote:
> +Mark

> I realize Mark has been out of the discussion, and what started as a DT
> problem actually turned into a PWM regulator discussion.
> Maybe we should start a new thread.

Probably, you're lucky I even looked at this - the number of irrelevant
patches I get CCed on is such that I'll often delete things that look
irrelevant unread.  I'm unsure what the relevance is, it looks like it's
mainly a discussion about pinctrl?

> As I said, the problem you're describing (pins muxed to the PWM device
> when it should actually stay in gpio+input mode) is not new, and the old
> pwm-regulator and pwm-rockchip implementation (before my atomic PWM
> changes) were behaving the same way.

Why would this make any kind of sense?

> What is new though, is the pwm_regulator_init_state() function [1], and
> it seems it's now preventing the probe of a pwm-regulator device if the
> initial PWM state is not described in the voltage-table.

> The question is, what should we do?

> 1/ Force users to put an entry matching this state (which means
>    breaking DT compat)
> 2/ Put a valid value in drvdata->state even if it's not reflecting the
>    real state
> 3/ Patch regulator core to support an "unknown-selector" return code.

Could someone say what the actual problem was please?  That was a very
long e-mail so I might be missing something but the obvious thing seems
to be to force a state since we'll be doing that when we enable anyway.
Or just not have the voltage table and use it as a continuous regulator.

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