From: "Vaittinen, Matti" <Matti.Vaittinen@fi.rohmeurope.com>
To: "broonie@kernel.org" <broonie@kernel.org>
Cc: "corbet@lwn.net" <corbet@lwn.net>,
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Subject: Re: [PATCH v5 01/16] dt-bindings: regulator: Document ROHM BD71282 regulator bindings
Date: Tue, 10 Dec 2019 11:14:48 +0000 [thread overview]
Message-ID: <ccc533df4e00bdcbe18ea45a0e0679161ff41354.camel@fi.rohmeurope.com> (raw)
In-Reply-To: <20191129120925.GA5747@sirena.org.uk>
Hello Mark,
On Fri, 2019-11-29 at 12:09 +0000, Mark Brown wrote:
> On Fri, Nov 29, 2019 at 07:48:13AM +0000, Vaittinen, Matti wrote:
> > On Tue, 2019-11-19 at 19:36 +0000, Mark Brown wrote:
> The cpufreq code is all there in kernel - drivers/cpufreq. I can't
> remember if Android still has a custom governor in their trees but it
> doesn't really make much difference in terms of how it interacts with
> the regulator drivers.
>
> > Anyways, my idea was to set the inital voltage values for these
> > states
> > via DT - but allow the voltages to be changed at run-time too (I
> > guess
> > this idea is visible in the patch 12).
>
> It'd be much better if you could avoid putting the voltages in the
> binding if they're not strictly required.
You suggested in the other mail that it might be worth making a run-
level 'group' consisting only one buck for fast voltage changes via
GPIOs. So I am back to adding the run-level support to the BD71828
driver. Which lead me back to this.
The PMIC supports wide range of voltages for these DVS bucks - but only
4 of these voltages can be selected to be switched fast via GPIO line
states. Eg, in HW level we can set RUN0 voltage (selected when both
GPIO lines are LOW) to one register. RUN1 voltage (selected when one
GPIO is high, other low) to second register. Same for RUN2 and RUN3
voltages.
I could make this so that initially there is the HW default voltages
are read up by driver and cached to be used for each level. When new
voltage is requested by the consumer, correct RUN level is selected or
if matching voltage is not set to any RUN level, then it is written to
one of the run level registers (and cache).
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.
So I still think the DT bindings for setting these initial values might
be the most convenient way if we are not adding custom API for this.
Hence I plan to keep this binding. Please let me know if you have
better ideas or if this is absolutely a no go.
Br,
Matti Vaittinen
next prev parent reply other threads:[~2019-12-10 11:14 UTC|newest]
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 [this message]
2019-12-10 12:11 ` Mark Brown
2019-12-10 12:41 ` Vaittinen, Matti
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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