Re: [Letux-kernel] [RFC PATCH 0/3] Enable 1GHz support on omap36xx

From: Tony Lindgren <tony@atomide.com>
To: "H. Nikolaus Schaller" <hns@goldelico.com>
Cc: "Adam Ford" <aford173@gmail.com>,
	"André Roth" <neolynx@gmail.com>,
	Linux-OMAP <linux-omap@vger.kernel.org>,
	"Discussions about the Letux Kernel"
	<letux-kernel@openphoenux.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Andreas Kemnade" <andreas@kemnade.info>,
	"Nishanth Menon" <nm@ti.com>
Subject: Re: [Letux-kernel] [RFC PATCH 0/3] Enable 1GHz support on omap36xx
Date: Mon, 9 Sep 2019 09:32:36 -0700	[thread overview]
Message-ID: <20190909163236.GP52127@atomide.com> (raw)
In-Reply-To: <87420DBD-770F-4C32-9499-A3AEA5876E8A@goldelico.com>

Hi,

* H. Nikolaus Schaller <hns@goldelico.com> [190909 14:57]:
> Another question that came up by private mail from André was if we
> should better disable the turbo OPPs of omap34xx and 36xx by default
> (status = "disabled";) because there are concerns about overheating
> the chips and we have no thermal regulation like for omap4 & 5.
> 
> But this would mean that every board DTS would have to set it explicitly
> to "enabled".

Yes I started thinking about that too. I think there is a requirement
to do the scaling via the voltage processor for the higher modes.
And there needs to be some way to automatically change to a lower
OPP in some cases.

For normal OPPs, using the twl regulator directly should be OK.

For the higher modes, maybe we could pass the callback functions
from arch/arm/mach-omap2/voltage.c for the twl regulator so the
voltage processor hardware can handle them directly. Or add a
separate regulator driver operating the voltages like Nishanth
posted patches for earlier.

Regards,

Tony