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From: "Vaittinen, Matti" <Matti.Vaittinen@fi.rohmeurope.com>
To: "broonie@kernel.org" <broonie@kernel.org>
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Subject: Re: [PATCH v5 01/16] dt-bindings: regulator: Document ROHM BD71282 regulator bindings
Date: Tue, 10 Dec 2019 12:41:47 +0000
Message-ID: <557a4c5993a6fb16710342438f74f92bdfb40ec0.camel@fi.rohmeurope.com> (raw)
In-Reply-To: <20191210121129.GA6110@sirena.org.uk>

Hello Mark,

On Tue, 2019-12-10 at 12:11 +0000, Mark Brown wrote:
> On Tue, Dec 10, 2019 at 11:14:48AM +0000, Vaittinen, Matti wrote:
> 
> > Problem is that if no default voltages are given from DT, the the
> > first
> > voltage changes are likely to be slow (require register access - I
> > guess the HW defaults are not working for many use-cases) - which
> > may
> > be undesirable.
> 
> I don't think that's likely to be a practical problem, and it's not
> likely it'd be worse than always doing writes.  A lot of things are
> slower the first time you do them and you're still going to have to
> do the writes no matter what.

The thing is that if we do initial setting of voltages (based on
binding data) we can set the voltages to registers before we switch to
that run-level. If we don't do initial setting then we will only do
setting when voltage change is actually requested - which may be too
late. (I actually heard somewhere that there is 40 uS time limit - but
I don't see how this is counted. Starting from what? - and I don't see
how this is guaranteed even with GPIO if interrupts are to be served).

OTOH, I also heard that the SoC probably require at least two of the
bucks to be controlled as a group (bucks connected to SRAM and CORE) -
probably all four.

So, I am again wondering if I should just upstream the basic control
with I2C for SoCs which do not require fast DVS voltage changes and
perhaps maintain/provide own set of patches with additional interface
for run-level control for those customers who require it... Sorry for
being such a difficult guy. Decision making seems to not be my strong
point :/

Br,
	Matti Vaittinen

  reply index

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-18  6:53 [PATCH v5 00/16] Support ROHM BD71828 PMIC Matti Vaittinen
2019-11-18  6:53 ` [PATCH v5 01/16] dt-bindings: regulator: Document ROHM BD71282 regulator bindings Matti Vaittinen
2019-11-18 16:25   ` Mark Brown
2019-11-18 18:03     ` Vaittinen, Matti
2019-11-19 18:13       ` Mark Brown
2019-11-19 18:51         ` Vaittinen, Matti
2019-11-19 19:36           ` Mark Brown
2019-11-29  7:48             ` Vaittinen, Matti
2019-11-29 12:09               ` Mark Brown
2019-12-02  7:57                 ` Vaittinen, Matti
2019-12-02 13:11                   ` Mark Brown
2019-12-02 14:02                     ` Vaittinen, Matti
2019-12-04 12:47                       ` Mark Brown
2019-12-04 13:13                         ` Vaittinen, Matti
2019-12-04 14:14                           ` Mark Brown
2019-12-10 10:39                             ` Vaittinen, Matti
2019-12-10 11:14                 ` Vaittinen, Matti
2019-12-10 12:11                   ` Mark Brown
2019-12-10 12:41                     ` Vaittinen, Matti [this message]
2019-12-10 12:45                       ` Mark Brown
2019-12-10 13:07                         ` Vaittinen, Matti
2019-11-22 22:48   ` Rob Herring
2019-11-18  6:54 ` [PATCH v5 02/16] dt-bindings: leds: ROHM BD71282 PMIC LED driver Matti Vaittinen
2019-11-22 23:00   ` Rob Herring
2019-11-18  6:54 ` [PATCH v5 03/16] dt-bindings: mfd: Document ROHM BD71828 bindings Matti Vaittinen
2019-11-22 23:05   ` Rob Herring
2019-11-18  6:55 ` [PATCH v5 04/16] mfd: rohm PMICs - use platform_device_id to match MFD sub-devices Matti Vaittinen
2019-11-18  6:55 ` [PATCH v5 05/16] mfd: bd71828: Support ROHM BD71828 PMIC - core Matti Vaittinen
2019-11-18  6:56 ` [PATCH v5 06/16] mfd: input: bd71828: Add power-key support Matti Vaittinen
2019-11-18  6:56 ` [PATCH v5 07/16] clk: bd718x7: Support ROHM BD71828 clk block Matti Vaittinen
2019-11-18  6:57 ` [PATCH v5 08/16] regulator: bd718x7: Split driver to common and bd718x7 specific parts Matti Vaittinen
2019-11-18  6:57 ` [PATCH v5 09/16] regulator: bd71828: Basic support for ROHM bd71828 PMIC regulators Matti Vaittinen
2019-11-18 16:20   ` Mark Brown
2019-11-19  9:12     ` Vaittinen, Matti
2019-11-18  6:58 ` [PATCH v5 10/16] gpio: devres: Add devm_gpiod_get_parent_array Matti Vaittinen
2019-11-19 14:43   ` Linus Walleij
2019-11-19 17:54     ` Vaittinen, Matti
2019-11-21 14:13       ` Linus Walleij
2019-11-18  6:59 ` [PATCH v5 11/16] docs: driver-model: Add missing managed GPIO array get functions Matti Vaittinen
2019-11-18  6:59 ` [PATCH v5 12/16] regulator: bd71828: Add GPIO based run-level control for regulators Matti Vaittinen
2019-11-18  7:00 ` [PATCH v5 13/16] rtc: bd70528 add BD71828 support Matti Vaittinen
2019-12-10 13:24   ` Alexandre Belloni
2019-11-18  7:01 ` [PATCH v5 14/16] gpio: bd71828: Initial support for ROHM BD71828 PMIC GPIOs Matti Vaittinen
2019-11-18  9:22   ` Bartosz Golaszewski
2019-11-18  7:03 ` [PATCH v5 15/16] leds: Add common LED binding parsing support to LED class/core Matti Vaittinen
2019-11-18 21:55   ` Jacek Anaszewski
2019-11-19  7:21     ` Vaittinen, Matti
2019-11-19 19:30       ` Jacek Anaszewski
2019-11-20  7:31         ` Vaittinen, Matti
2019-11-19 14:23   ` Vaittinen, Matti
2019-11-18  7:03 ` [PATCH v5 16/16] led: bd71828: Support LED outputs on ROHM BD71828 PMIC Matti Vaittinen

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