linux-kernel - Re: [PATCH 8/9] regulator: bd71837: BD71837 PMIC regulator driver

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Message-ID: <20180525050825.GA16888@localhost.localdomain>
Date:   Fri, 25 May 2018 08:08:25 +0300
From:   Matti Vaittinen <mazziesaccount@...il.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     "Vaittinen, Matti" <Matti.Vaittinen@...rohmeurope.com>,
        "mturquette@...libre.com" <mturquette@...libre.com>,
        "sboyd@...nel.org" <sboyd@...nel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "lee.jones@...aro.org" <lee.jones@...aro.org>,
        "lgirdwood@...il.com" <lgirdwood@...il.com>,
        "mazziesaccount@...il.com" <mazziesaccount@...il.com>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Mutanen, Mikko" <Mikko.Mutanen@...rohmeurope.com>,
        "Haikola, Heikki" <Heikki.Haikola@...rohmeurope.com>
Subject: Re: [PATCH 8/9] regulator: bd71837: BD71837 PMIC regulator driver

On Thu, May 24, 2018 at 06:59:40PM +0100, Mark Brown wrote:
> On Thu, May 24, 2018 at 05:51:27PM +0000, Vaittinen, Matti wrote:
> 
> > > what is the lock doing and what is this wrapper function intended to do?
> 
> > This was the other spot which I was unsure how to handle. Datasheet for
> > the chip says that if voltage is to be changed, the regulator must be
> > disabled. Thus my voltage changing function checks if regulator is enabled
> 
> Ugh, this chip is not very good is it?
I am not the correct guy to judge that as I don't have too wide
experience on PMICs. (This is first PMIC I have been working with).
Probably this chip has some other advantages and is thus used.

>  Don't bounce the supply to
> change the voltage silently, that's clearly a bad idea - the devices
> using the supply are going to get very upset when the power gets removed
> just because they changed the voltage.  Instead implement a custom set
> operation that returns an error if the user attempts to change the
> voltage while the regualtor is enabled.

Makes perfect sense. I will change the operation to this.

Br,
    Matti Vaittinen