linux-kernel - Re: [PATCH v6 1/1] mfd: arizona: Export functions to control subsystem DVFS

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 19 May 2015 16:23:51 +0100
From:	Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
To:	Richard Fitzgerald <rf@...nsource.wolfsonmicro.com>
Cc:	lee.jones@...aro.org, broonie@...nel.org,
	linux-kernel@...r.kernel.org, patches@...nsource.wolfsonmicro.com
Subject: Re: [PATCH v6 1/1] mfd: arizona: Export functions to control
	subsystem DVFS

On Tue, May 19, 2015 at 03:57:42PM +0100, Richard Fitzgerald wrote:
> The WM5102, WM8997, WM8998 and WM1814 codecs have an internal dynamic
> clock booster. When this booster is active, the DCVDD voltage must be
> increased. If all the currently active audio paths can run with the root
> SYSCLK we can disable the booster, allowing us to turn down DCVDD voltage
> to save power.
> 
> Previously this was being done by having the booster enable bit set
> as a side-effect of the LDO1 regulator driver, which is unexpected
> behaviour of a regulator and not compatible with using an external
> regulator.
> 
> This patch exports functions to handle the booster enable and
> DCVDD voltage, with each relevant subsystem flagging whether it can
> currently run without the booster. Note that these subsystems are
> stateless and none of them are nestable, so there's no need for
> reference counting, we only need a simple boolean for each subsystem
> of whether their current condition could require the booster or will
> allow us to turn the codec down to lower operating power.
> 
> Signed-off-by: Richard Fitzgerald <rf@...nsource.wolfsonmicro.com>
> ---

Reviewed-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>

Thanks,
Charles
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/