linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Markus Pargmann <mpa@pengutronix.de>
To: Mark Brown <broonie@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>,
	Wolfram Sang <wsa@the-dreams.de>,
	kernel@pengutronix.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] regulator: max8660: Remove boot_on handling
Date: Tue, 24 Mar 2015 17:49:22 +0100	[thread overview]
Message-ID: <20150324164922.GM28604@pengutronix.de> (raw)
In-Reply-To: <20150324162226.GG17265@sirena.org.uk>

[-- Attachment #1: Type: text/plain, Size: 1583 bytes --]

On Tue, Mar 24, 2015 at 09:22:27AM -0700, Mark Brown wrote:
> On Tue, Mar 24, 2015 at 01:08:02PM +0100, Markus Pargmann wrote:
> 
> > boot_on is handled by the regulator core. It will call enable() on the
> > regulators that are specified to be boot_on. So we don't require any
> > additional handling in this driver
> 
> >  		switch (pdata->subdevs[i].id) {
> >  		case MAX8660_V3:
> > -			if (boot_on)
> > -				max8660->shadow_regs[MAX8660_OVER1] |= 1;
> > -			break;
> > -
> 
> So, this is updating the register default value rather than writing to
> the device.  That suggests that the purpose is to either avoid needless
> write outs to the device or something, or at the very least it's not a
> completely direct reimplementation of the core functionality.  It is
> certainly underdocumented at the minute (and the driver probably wants
> to be converted to regmap) but this makes me a bit cautious about
> obvious cleanups missing something.

Sorry, this patch is wrong. I just realized that this chip is write-only
and has different regulators that share the same registers. So it is
impossible to selectively enable some regulators without accidentaly
disabling others that may be enabled. So the code is necessary.

Thanks,

Markus

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

      reply	other threads:[~2015-03-24 16:49 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-24 12:08 [PATCH 1/2] regulator: max8660: Remove boot_on handling Markus Pargmann
2015-03-24 12:08 ` [PATCH 2/2] regulator: max8660: Add error message for missing regulator data Markus Pargmann
2015-03-24 12:38   ` Wolfram Sang
2015-03-24 16:36     ` Markus Pargmann
2015-03-24 16:08   ` Mark Brown
2015-03-24 16:40     ` Markus Pargmann
2015-03-24 17:07       ` Mark Brown
2015-03-24 16:22 ` [PATCH 1/2] regulator: max8660: Remove boot_on handling Mark Brown
2015-03-24 16:49   ` Markus Pargmann [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20150324164922.GM28604@pengutronix.de \
    --to=mpa@pengutronix.de \
    --cc=broonie@kernel.org \
    --cc=kernel@pengutronix.de \
    --cc=lgirdwood@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=wsa@the-dreams.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).