linux-kernel - Re: [alsa-devel] [PATCH v6 1/3] clk: x86: Add Atom PMC platform clocks

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Date:   Thu, 15 Dec 2016 23:15:37 -0600
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Stephen Boyd <sboyd@...eaurora.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     ALSA Development Mailing List <alsa-devel@...a-project.org>,
        Irina Tirdea <irina.tirdea@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Michael Turquette <mturquette@...libre.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Takashi Iwai <tiwai@...e.com>,
        platform-driver-x86@...r.kernel.org,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Brown <broonie@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Darren Hart <dvhart@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Len Brown <lenb@...nel.org>, linux-clk@...r.kernel.org,
        Pierre-Louis Bossart <pierre-louis.bossart@...el.com>
Subject: Re: [alsa-devel] [PATCH v6 1/3] clk: x86: Add Atom PMC platform
 clocks

Hi Stephen,

can you elaborate on the last comment?

thanks,

-Pierre


On 12/13/2016 05:25 PM, Stephen Boyd wrote:
>
>>> +                                       void __iomem *base,
>>> +                                       const char **parent_names,
>>> +                                       int num_parents)
>>> +{
>>> +       struct clk_plt *pclk;
>>> +       struct clk_init_data init;
>>> +       int ret;
>>> +
>>> +       pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
>>> +       if (!pclk)
>>> +               return ERR_PTR(-ENOMEM);
>>> +
>>> +       init.name =  kasprintf(GFP_KERNEL, "%s%d", PLT_CLK_NAME_BASE, id);
>> devm_kasprintf()
> Please no.
>
>>> +       init.ops = &plt_clk_ops;
>>> +       init.flags = 0;
>>> +       init.parent_names = parent_names;
>>> +       init.num_parents = num_parents;
>>> +
>>> +       pclk->hw.init = &init;
>>> +       pclk->reg = base + id * PMC_CLK_CTL_SIZE;
>>> +       spin_lock_init(&pclk->lock);
>>> +
>>> +       ret = devm_clk_hw_register(&pdev->dev, &pclk->hw);
>>> +       if (ret)
>>> +               goto err_free_init;
>>> +
>>> +       pclk->lookup = clkdev_hw_create(&pclk->hw, init.name, NULL);
>>> +       if (!pclk->lookup) {
>>> +               ret = -ENOMEM;
>>> +               goto err_free_init;
>>> +       }
>>> +
>>> +       kfree(init.name);
>> devm_kfree();
> It's all local to this function, devm isn't helping anything.
> Having one kfree() would be good though. And using init.name for
> the clkdev lookup is probably wrong and should be replaced with
> something more generic along with an associated device name.
I am not sure I understand this last comment.
init.name is not a constant, it's made of the "pmc_plt_clk_" string 
concatenated with an id which directly maps to which hardware clock is 
registered. Clients use devm_clk_get() with a "pmc_plt_clk_<n>" argument.
>