Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings

From	Viresh Kumar <viresh.kumar@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings
Date	2017-07-13 07:20 +0200
Message-ID	<u2EHD-1nz-9@gated-at.bofh.it> (permalink)
References	<u2jtv-4CF-3@gated-at.bofh.it> <u2jtw-4CF-7@gated-at.bofh.it> <u2xmP-53z-27@gated-at.bofh.it> <u2Cw9-8eu-11@gated-at.bofh.it>
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On 13-07-17, 10:52, Chen-Yu Tsai wrote:
> I'm afraid the regulator case still doesn't make sense. The voltage
> constraints should be set within each supplies device node. This was
> explained in the discussion in v1 [1].

I thought we were discussing about something I mentioned in one of my example
but never to a point that the regulator problem doesn't exist at all. Perhaps I
misunderstood your concerns. Anyway, lemme try once more with a better example.

Regulator shared by: LCD and MMC (both can do DVFS) and the min/max constraint
that can be set by the consumers of the regulator (both LCD/MMC) are: 1.5 V to
3 V.

The bootloader has programmed the LCD to work at the highest pixel frequency,
which needs the voltage to be in range from 2.5 - 3 V.

Now MMC can get probed first and it can try to bring the voltages below 2.5 V.
Though, 1.5 - 2.5 is a valid range for the LCD, but not at the current pixel
frequency.

Does that sound like a valid problem?

-- 
viresh

Thread

[RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-12 08:40 +0200
  Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings Rob Herring <robh+dt@kernel.org> - 2017-07-12 23:30 +0200
    Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings Chen-Yu Tsai <wens@csie.org> - 2017-07-13 05:00 +0200
      Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-13 07:20 +0200
        Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings Chen-Yu Tsai <wens@csie.org> - 2017-07-13 11:50 +0200
          Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-13 12:00 +0200
    Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-13 11:40 +0200
      Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings Rob Herring <robh@kernel.org> - 2017-07-17 19:40 +0200
        Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-18 08:00 +0200

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