linux-kernel - Re: Where to update regulator register with initial voltage set by HW

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Message-ID: <CAHKzcEPLRB9YTXxjgx=m0bcDjo+fbbNqVh3BrZHB5EyoY7aPxw@mail.gmail.com>
Date:   Fri, 30 Jun 2017 17:25:38 +0200
From:   Waldemar Rymarkiewicz <waldemar.rymarkiewicz@...il.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     linux-kernel@...r.kernel.org, Liam Girdwood <lgirdwood@...il.com>,
        "Bartholomae, Thomas" <t.bartholomae@...el.com>
Subject: Re: Where to update regulator register with initial voltage set by HW

On 30 June 2017 at 14:14, Mark Brown <broonie@...nel.org> wrote:
> On Fri, Jun 30, 2017 at 01:37:32PM +0200, Waldemar Rymarkiewicz wrote:
>
>> I am not sure if I understand. Do you mean, a regulator should
>> determine a voltage and update a register with a right selector when
>> system boots, so the regulator framework reading reg register knows
>> actual voltage?
>
> Just don't provide a default value for the cache, regmap will do a
> physical read if there's nothing in the cache for that register and
> everything will work transparently.

Just want to understand well. "Physical read" means to read a register
value? or determine actual value another way? As Thomas mentioned in
previous email TPS65275 does not have a circuit to determine startup
voltage at least I cannot see this in the datasheet.

Data sheet: http://www.ti.com/lit/gpn/tps65273v

/Waldek