Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323 regulator

From	Mark Brown <broonie@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323 regulator
Date	2016-02-03 13:40 +0100
Message-ID	<qY4T0-1Xc-15@gated-at.bofh.it> (permalink)
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On Wed, Feb 03, 2016 at 01:39:02PM +0800, menghui lin wrote:
> On Tue, 2016-02-02 at 19:38 +0000, Mark Brown wrote:

> > How does the driver know if it needs to change the mode (ie, how can it
> > tell if the current mode is inadequate) and surely if we can only change
> > in one direction this isn't terribly useful?

> I think the datasheet of buck/ldo could provide information about power
> capability of each mode. The driver should adjust regulator mode per its
> device's power requirement.

That's of no help for a consumer driver which doesn't know what
regulator is supplying it.

> case 1:

> We have a USB typeC micro-controller, which has two modes - standby and
> normal. It requires 1.8V and 3.3V to operate (both powers are always
> on). The device stays in standby mode when there is no cable in. When
> cable in, we got an interrupt and change device into normal mode.

> The standby mode power consumption is quite small, so we would like the
> change mode of regulator into STANDBY to save more power. And we change
> into NORMAL when we receive cable-in interrupt.

This seems like something that we ought to be doing via runtime PM
anyway which should be going through the suspend mode bindings, though
that would need some plumbing in.

> case 2:

> About buck regulator for CPU, it usually provides PWM mode, PWM/PFM Auto
> mode, PFM mode. I think it could map to FAST, NORMAL, IDLE mode
> respectively. Most of time we would use just normal mode. However, we
> would change regulator into PWM mode time to time to test buck output
> performance on the tested board.

That's a test use that doesn't seem a good fit for upstream at all.

Thread

Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323  regulator John Crispin <blogic@openwrt.org> - 2016-01-28 19:20 +0100
  Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323  regulator Mark Brown <broonie@kernel.org> - 2016-01-29 00:20 +0100
    Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323  regulator menghui lin <menghui.lin@mediatek.com> - 2016-01-29 11:00 +0100
      Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323  regulator Mark Brown <broonie@kernel.org> - 2016-01-29 12:30 +0100
        Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323  regulator menghui lin <menghui.lin@mediatek.com> - 2016-01-29 13:20 +0100
          Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323  regulator Mark Brown <broonie@kernel.org> - 2016-02-02 20:40 +0100
          Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323  regulator Mark Brown <broonie@kernel.org> - 2016-02-02 20:40 +0100
            Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323  regulator menghui lin <menghui.lin@mediatek.com> - 2016-02-03 06:40 +0100
              Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323  regulator Mark Brown <broonie@kernel.org> - 2016-02-03 13:40 +0100
                Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323  regulator menghui lin <menghui.lin@mediatek.com> - 2016-02-04 03:50 +0100

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