From: khilman@kernel•org (Kevin Hilman)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v3] PM / AVS: rockchip-io: add driver handling Rockchip io domains
Date: Wed, 24 Sep 2014 16:27:07 -0700 [thread overview]
Message-ID: <7hwq8sk3as.fsf@deeprootsystems.com> (raw)
In-Reply-To: <7hy4tog61r.fsf@deeprootsystems.com> (Kevin Hilman's message of "Fri, 12 Sep 2014 09:25:04 -0700")
Kevin Hilman <khilman@kernel•org> writes:
> Rafael,
>
> Doug Anderson <dianders@chromium•org> writes:
>
>> From: Heiko St?bner <heiko@sntech•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 St?bner <heiko@sntech•de>
>> Signed-off-by: Doug Anderson <dianders@chromium•org>
>> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti•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@linaro•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
prev parent reply other threads:[~2014-09-24 23:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-11 22:48 [PATCH v3] PM / AVS: rockchip-io: add driver handling Rockchip io domains Doug Anderson
2014-09-12 16:25 ` Kevin Hilman
2014-09-24 23:27 ` Kevin Hilman [this message]
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