From: Viresh Kumar <viresh.kumar@linaro.org>
To: Chen-Yu Tsai <wens@csie.org>
Cc: Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Stephen Boyd <sboyd@codeaurora.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Mark Brown <broonie@kernel.org>,
Rajendra Nayak <rnayak@codeaurora.org>,
Shiraz Hashim <shashim@codeaurora.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings
Date: Thu, 13 Jul 2017 10:39:34 +0530 [thread overview]
Message-ID: <20170713050934.GB352@vireshk-i7> (raw)
In-Reply-To: <CAGb2v67XtUcqdjMt-Ln6zn3ShH4JFmjkK4bPSpUNZpJqnmwivw@mail.gmail.com>
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
next prev parent reply other threads:[~2017-07-13 5:09 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-12 6:34 [RFC v2 0/6] drivers: Boot Constraints core Viresh Kumar
2017-07-12 6:34 ` [RFC v2 1/6] drivers: Add boot constraints core Viresh Kumar
2017-07-12 6:34 ` [RFC v2 2/6] drivers: boot_constraint: Add support for supply constraints Viresh Kumar
2017-07-12 6:34 ` [RFC v2 3/6] drivers: boot_constraint: Add boot_constraints_disable kernel parameter Viresh Kumar
2017-07-12 6:34 ` [RFC v2 4/6] drivers: boot_constraint: Add debugfs support Viresh Kumar
2017-07-12 7:18 ` Viresh Kumar
2017-07-12 6:34 ` [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings Viresh Kumar
2017-07-12 21:28 ` Rob Herring
2017-07-13 2:52 ` Chen-Yu Tsai
2017-07-13 5:09 ` Viresh Kumar [this message]
2017-07-13 9:46 ` Chen-Yu Tsai
2017-07-13 9:51 ` Viresh Kumar
2017-07-13 9:36 ` Viresh Kumar
2017-07-17 17:34 ` Rob Herring
2017-07-18 5:58 ` Viresh Kumar
2017-07-12 6:34 ` [RFC v2 6/6] drivers: boot_constraint: Add constraints for OF devices Viresh Kumar
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