linux-kernel - Re: [PATCH 2/7] soc: davinci: new genpd driver

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Message-ID: <CAMRc=Mf+S3k_wfhUWEx2-39AZx1szkgy-u-bsZQUMiaY06UKww@mail.gmail.com>
Date:   Thu, 8 Feb 2018 10:54:49 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Sekhar Nori <nsekhar@...com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Kevin Hilman <khilman@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        David Lechner <david@...hnology.com>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH 2/7] soc: davinci: new genpd driver

2018-02-08 10:30 GMT+01:00 Sekhar Nori <nsekhar@...com>:
> On Wednesday 07 February 2018 07:15 PM, Bartosz Golaszewski wrote:
>> +     /*
>> +      * DaVinci always uses a single clock for power-management. We assume
>> +      * it's the first one in the clocks property.
>> +      */
>> +     clk = of_clk_get(dev->of_node, 0);
>> +     if (IS_ERR(clk))
>> +             return PTR_ERR(clk);
>
> We already get this today with drivers/base/power/clock_ops.c once
> .con_ids list is dropped from pm_clk_notifier_block (which I think it
> should).
>
> If there is no reason to introduce thus functionality at this stage,
> perhaps we should wait till such a time when its clearly needed?
>
> Thanks,
> Sekhar

If I understand correctly: once we drop the con_ids list, we end up
calling clk_get(dev, NULL) from pm_clk_acquire(), which matches
against the clock with NULL con_id, which may not necessarily be the
first clock in the list.

I'm working on extending the psc driver with the power-domain code (as
suggested by David), which should be much smaller and simplier - how
about that?

Thanks,
Bartosz