linux-kernel - Re: [PATCH 0/7] ARM: davinci: add genpd support

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Message-ID: <a736d727-5805-94ea-3e40-34fc4a6267ef@ti.com>
Date:   Fri, 9 Feb 2018 18:12:00 +0530
From:   Sekhar Nori <nsekhar@...com>
To:     David Lechner <david@...hnology.com>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Kevin Hilman <khilman@...nel.org>,
        Russell King <linux@...linux.org.uk>
CC:     <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH 0/7] ARM: davinci: add genpd support

Hi David,

On Thursday 08 February 2018 04:13 AM, David Lechner wrote:
> On 02/07/2018 07:45 AM, Bartosz Golaszewski wrote:
>> From: Bartosz Golaszewski <bgolaszewski@...libre.com>
>>
>> Hi Sekhar et al,
>>
>> please take a look at the following patches. They add a simple genpd
>> driver and use it in DT mode on da850 boards.
>>
>> I was trying to use genpd in legacy mode too, but couldn't find neither
>> any interfaces nor users that would do that. For now I added a check in
>> arch/arm/mach-davinci/pm_domain.c that disables the clock pm setup if
>> we're using genpd.
>>
>> This series applies on top of and has been tested with David Lechner's
>> for-bartosz branch. It fixes the clock look-up issues we faced with
>> lcdc and emac.
> 
> I'm starting to think that it makes more sense to just make the PSC driver
> a power-domain and reset provider rather than a clock provider. It is
> unfortunate that genpd is DT only.

This will mean that the only way to enable clocks on DaVinci is to use
pm_runtime() calls. We do still have drivers which depend on clk api for
enabling clocks, so I am not sure its feasible just yet.

I think a question like this can arise for any gate clock.

Thanks,
Sekhar