linux-kernel - Re: [PATCH] spi: cadence-quadspi: Fix clock enable underflows due to runtime PM

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Message-ID: <aTf6RRAveRdVnWQZ@sirena.co.uk>
Date: Tue, 9 Dec 2025 19:30:29 +0900
From: Mark Brown <broonie@...nel.org>
To: "Dutta, Anurag" <a-dutta@...com>
Cc: Nishanth Menon <nm@...com>, Francesco Dolcini <francesco@...cini.it>,
	Siddharth Vadapalli <s-vadapalli@...com>, linux-spi@...r.kernel.org,
	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	"Gujulan Elango, Hari Prasath" <gehariprasath@...com>,
	"Kumar, Udit" <u-kumar1@...com>
Subject: Re: [PATCH] spi: cadence-quadspi: Fix clock enable underflows due to
 runtime PM

On Tue, Dec 09, 2025 at 03:22:43PM +0530, Dutta, Anurag wrote:
> On 09-12-2025 11:13, Dutta, Anurag wrote:

> Another solution :

> diff --git a/drivers/spi/spi-cadence-quadspi.c
> b/drivers/spi/spi-cadence-quadspi.c
> index af6d050da1c8..4d298b945f09 100644
> --- a/drivers/spi/spi-cadence-quadspi.c
> +++ b/drivers/spi/spi-cadence-quadspi.c
> @@ -2024,7 +2024,11 @@ static int cqspi_probe(struct platform_device *pdev)
>  probe_reset_failed:
>         if (cqspi->is_jh7110)
>                 cqspi_jh7110_disable_clk(pdev, cqspi);
> -       clk_disable_unprepare(cqspi->clk);
> +
> +       if (!(ddata && (ddata->quirks & CQSPI_DISABLE_RUNTIME_PM))) {
> +               if (pm_runtime_get_sync(&pdev->dev) >= 0)
> +                       clk_disable_unprepare(cqspi->clk);
> +       }

> pm_runtime_get_sync() will increment the usage count thereby preventing from
> runtime_suspend()
> getting invoked, thereby preventing double clock_disable()
> 
> This will work for !CONFIG_PM as well because pm_runtime_get_sync() will
> return 1 then.
> and the runtime_suspend() is never going to be invoked.

I think we want this, possibly using pm_runtime_force_resume() instead
(not 100% sure on that one, glancing at the documentation there might be
issues though it feels like the intent of what we're doing here).  Can
you send a patch please?

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