linux-kernel - Re: [PATCH] memory: tegra: Remove calls to dev_pm_opp_set

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Message-ID: <20210125031024.g6limtpu4ozzp2mr@vireshk-i7>
Date:   Mon, 25 Jan 2021 08:40:24 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Krzysztof Kozlowski <krzk@...nel.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        linux-kernel@...r.kernel.org, linux-tegra@...r.kernel.org
Subject: Re: [PATCH] memory: tegra: Remove calls to dev_pm_opp_set_clkname()

On 22-01-21, 18:00, Dmitry Osipenko wrote:
> 22.01.2021 09:00, Viresh Kumar пишет:
> > There is no point calling dev_pm_opp_set_clkname() with the "name"
> > parameter set to NULL, this is already done by the OPP core at setup
> > time and should work as it is.
> > 
> > Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> > ---
> > Dmitry, am I missing something obvious here ?
> 
> The dev_pm_opp_set_clkname() ensures that the OPP table has a clk
> assigned to the table.
> 
> The _allocate_opp_table() ignores all clk_get() errors except the
> -EPROBE_DEFER.

That is the case for everyone relying on OPP core to get it. It should be fine
for this case as well.

> The opp_table->clk must be not a PTR_ERR for these memory drivers.
> 
> On the other hand, the memory drivers also do the devm_clk_get()
> themselves, hence technically clk_get() of _allocate_opp_table()
> shouldn't fail. But I'll need to take a closer look at the clk core, to
> check whether clk_get() could fail for the implicit _allocate_opp_table().
> 
> Tegra124-emc driver also has dev_pm_opp_set_clkname(), BTW.

-- 
viresh