Message-ID: <7hwq8sk3as.fsf@deeprootsystems.com>
Date:	Wed, 24 Sep 2014 16:27:07 -0700
From:	Kevin Hilman <khilman@...nel.org>
To:	Doug Anderson <dianders@...omium.org>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Heiko Stuebner <heiko@...ech.de>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Santosh Shilimkar <santosh.shilimkar@...com>,
	Nishanth Menon <nm@...com>,
	Linus Walleij <linus.walleij@...aro.org>, olof@...om.net,
	Arnd Bergmann <arnd@...db.de>, Mark Brown <broonie@...nel.org>,
	Addy Ke <addy.ke@...k-chips.com>,
	Sonny Rao <sonnyrao@...omium.org>,
	linux-arm-kernel@...ts.infradead.org, robh+dt@...nel.org,
	pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	sre@...nel.org, Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	dwmw2@...radead.org, grant.likely@...aro.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org, linux-rockchip@...ts.infradead.org
Subject: Re: [PATCH v3] PM / AVS: rockchip-io: add driver handling Rockchip io domains

Kevin Hilman <khilman@...nel.org> writes:

> Rafael,
>
> Doug Anderson <dianders@...omium.org> writes:
>
>> From: Heiko Stübner <heiko@...ech.de>
>>
>> IO domain voltages on some Rockchip SoCs are variable but need to be
>> kept in sync between the regulators and the SoC using a special
>> register.
>>
>> A specific example using rk3288:
>> - If the regulator hooked up to a pin like SDMMC0_VDD is 3.3V then
>>   bit 7 of GRF_IO_VSEL needs to be 0.  If the regulator hooked up to
>>   that same pin is 1.8V then bit 7 of GRF_IO_VSEL needs to be 1.
>>
>> Said another way, this driver simply handles keeping bits in the SoC's
>> general register file (GRF) in sync with the actual value of a voltage
>> hooked up to the pins.
>>
>> Note that this driver specifically doesn't include:
>> - any logic for deciding what voltage we should set regulators to
>> - any logic for deciding whether regulators (or internal SoC blocks)
>>   should have power or not have power
>>
>> If there were some other software that had the smarts of making
>> decisions about regulators, it would work in conjunction with this
>> driver.  When that other software adjusted a regulator's voltage then
>> this driver would handle telling the SoC about it.  A good example is
>> vqmmc for SD.  In that case the dw_mmc driver simply is told about a
>> regulator.  It changes the regulator between 3.3V and 1.8V at the
>> right time.  This driver notices the change and makes sure that the
>> SoC is on the same page.
>>
>> Signed-off-by: Heiko Stübner <heiko@...ech.de>
>> Signed-off-by: Doug Anderson <dianders@...omium.org>
>> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@...com>
>> ---
>> Changes in v3:
>> - Changed compatible string as per Santosh.
>
> Thanks, I like the new string better.
>
>> - Added code docs about the slop in 1.8V and 3.3V as per Santosh.
>> - Moved some #defines to the top as per Santosh.
>
> All nice changes, thanks Santosh!
>
> Reviewed-by: Kevin Hilman <khilman@...aro.org>
>
> Rafael, how do you want to handle drivers/avs/* ?  Along with Nishanth,
> I'm maintaining everything there currently (only one driver :)), and
> since I recommended $SUBJECT driver go into drivers/avs[1], I'm happy to
> queue it for you and update MAINTAINERS to cover drivers/avs/* instead
> of just smartreflex.c.
>
> Let me know how you'd like to proceed.

For the benefit of the archives... Rafael and I talked off-list and
agreed that I'll queue it up for him and update MAINTAINERS to reflect
maintenance of drivesr/power/avs

Kevin
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