Re: [PATCH 2/6] regulator: anatop: only set supply regulator when it actually exists

From	Mark Brown <broonie@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/6] regulator: anatop: only set supply regulator when it actually exists
Date	2017-04-11 22:40 +0200
Message-ID	<tvaJX-3qG-7@gated-at.bofh.it> (permalink)
References	<tvaJX-3qG-9@gated-at.bofh.it> <tvaJX-3qG-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Apr 12, 2017 at 09:58:43AM +0800, Dong Aisheng wrote:
> Mandatorily set the initdata->supply_regulator while it actually not
> exist will cause regulator core to resolve supply each time whenever
> a new regulator registered which is meaningless and waste CPU mips.
> 
> We can observe more than one hundred times of iteration of resolving
> during a MX6Q SDB board booting up.
> 
> This patch adds the condition check for vin-supply to avoid the issue.

This is an obvious abstraction failure - there is nothing magical about
your driver which means that we need special casing in it to handle
badly written DTs that don't specify supplies.  Exactly the same
argument applies to all other regulators so if this is worth fixing it's
worth fixing in the core so we substitute in a dummy regulator if the
supply is genuinely missing.  Which is something we in fact have code to
do already though for some reason I can't see we bypass it, I'll send a
patch just now...

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Re: [PATCH 2/6] regulator: anatop: only set supply regulator when it  actually exists Mark Brown <broonie@kernel.org> - 2017-04-11 22:40 +0200
  Re: [PATCH 2/6] regulator: anatop: only set supply regulator when it  actually exists Dong Aisheng <dongas86@gmail.com> - 2017-04-12 17:20 +0200
    Re: [PATCH 2/6] regulator: anatop: only set supply regulator when it  actually exists Mark Brown <broonie@kernel.org> - 2017-04-12 18:00 +0200
      Re: [PATCH 2/6] regulator: anatop: only set supply regulator when it  actually exists Mark Brown <broonie@kernel.org> - 2017-04-12 18:10 +0200
      Re: [PATCH 2/6] regulator: anatop: only set supply regulator when it  actually exists Dong Aisheng <dongas86@gmail.com> - 2017-04-12 18:10 +0200

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