linux-kernel - Re: [RFC] Add gpio based voltage switching regulator

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Message-ID: <20110926125155.GH2946@opensource.wolfsonmicro.com>
Date:	Mon, 26 Sep 2011 13:51:55 +0100
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Heiko Stübner <heiko@...ech.de>
Cc:	Liam Girdwood <lrg@...com>, linux-kernel@...r.kernel.org
Subject: Re: [RFC] Add gpio based voltage switching regulator

On Mon, Sep 26, 2011 at 08:52:18AM +0200, Heiko Stübner wrote:

> This patch adds support for regulators that can switch between
> two voltage levels by setting a gpio.

This really should be scalable beyond two voltages, or at least prepared
for that possibility.

> Handling of set_voltage calls with a range that fits neither the
> low nor the high voltage is determined by the inbetween_high
> option. When set to 1 the high voltage is used, on 0 the low
> voltage is used and on -EINVAL an error is returned, disallowing
> the usage of the voltage range.

No, don't do this.  If you can't set the requested voltage then fail.
This is not in the least bit driver specific.

> I'm not hung up on the "inbetween handling", in fact at the moment it
> seems to not belong there. But I'm not sure on how to handle
> frequency tables like
> 	[0] = { 1000000, 1150000 },
> 	[1] = { 1150000, 1250000 },
> 	[2] = { 1250000, 1350000 },
> I.e. the middle value should use the voltage in 2 for switch regulators,
> but the defined value for more intelligent ones.

I'm afraid I can't parse this, sorry.

> @@ -0,0 +1,320 @@
> +/*
> + * switched.c

This needs a better name.

Otherwise this looks good, the main thing is the ability to support more
voltages.
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