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From: Enric Balletbo Serra <eballetbo@gmail.com>
Date: Tue, 11 Jul 2017 00:31:28 +0200
Message-ID: <CAFqH_51Mje4tK494JRgb=wWJNU9zu=WZ1sS482kRAvRrPpLkXQ@mail.gmail.com>
Subject: Re: [PATCH] clk: x86: Do not gate clocks enabled by the firmware
To: Carlo Caione <carlo@caione.org>
Cc: Michael Turquette <mturquette@baylibre.com>, linux-clk@vger.kernel.org,
	Darren Hart <dvhart@infradead.org>,
	Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>, Stephen Boyd <sboyd@codeaurora.org>,
	linux@endlessm.com, Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Carlo Caione <carlo@endlessm.com>
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List-ID: <linux-clk.vger.kernel.org>

Hi,

2017-07-10 22:38 GMT+02:00 Carlo Caione <carlo@caione.org>:
> From: Carlo Caione <carlo@endlessm.com>
>
> Read the enable register to determine if the clock is already in use by
> the firmware. In this case avoid gating the clock.
>
> Signed-off-by: Carlo Caione <carlo@endlessm.com>
> ---
>  drivers/clk/x86/clk-pmc-atom.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/clk/x86/clk-pmc-atom.c b/drivers/clk/x86/clk-pmc-atom.c
> index 2b60577703ef..46a8b6216fca 100644
> --- a/drivers/clk/x86/clk-pmc-atom.c
> +++ b/drivers/clk/x86/clk-pmc-atom.c
> @@ -185,6 +185,9 @@ static struct clk_plt *plt_clk_register(struct platform_device *pdev, int id,
>         pclk->reg = base + PMC_CLK_CTL_OFFSET + id * PMC_CLK_CTL_SIZE;
>         spin_lock_init(&pclk->lock);
>
> +       if (plt_clk_is_enabled(&pclk->hw))
> +               init.flags |= CLK_IGNORE_UNUSED;
> +
>         ret = devm_clk_hw_register(&pdev->dev, &pclk->hw);
>         if (ret) {
>                 pclk = ERR_PTR(ret);
> --
> 2.13.2
>

It also fixes the issue introduced in commit 282a4e4 ("platform/x86:
Enable Atom PMC platform clocks") that causes no audio on Baytrail.

Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Thanks Carlo to send this.