linux-kernel - Re: [PATCH v2 1/1] spi: spi-cadence-quadspi: Fix pm runtime unbalance

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Message-ID: <65124dfd-3f52-45b4-b514-222f47ec8baf@altera.com>
Date: Tue, 10 Jun 2025 16:22:37 -0700
From: Matthew Gerlach <matthew.gerlach@...era.com>
To: khairul.anuar.romli@...era.com, Mark Brown <broonie@...nel.org>,
 "open list:SPI SUBSYSTEM" <linux-spi@...r.kernel.org>,
 open list <linux-kernel@...r.kernel.org>,
 Khairul Anuar Romli <khairulanuar.romli@...era.com>
Subject: Re: [PATCH v2 1/1] spi: spi-cadence-quadspi: Fix pm runtime unbalance



On 6/10/25 3:30 PM, khairul.anuar.romli@...era.com wrote:
> From: Khairul Anuar Romli <khairul.anuar.romli@...era.com>
>
> Having PM put sync in remove function is causing PM underflow during
> remove operation. This is caused by the function, runtime_pm_get_sync,
> not being called anywhere during the op. Ensure that calls to
> pm_runtime_enable()/pm_runtime_disable() and
> pm_runtime_get_sync()/pm_runtime_put_sync() match.
>
> echo 108d2000.spi > /sys/bus/platform/drivers/cadence-qspi/unbind
> [   49.644256] Deleting MTD partitions on "108d2000.spi.0":
> [   49.649575] Deleting u-boot MTD partition
> [   49.684087] Deleting root MTD partition
> [   49.724188] cadence-qspi 108d2000.spi: Runtime PM usage count underflow!
>
> Continuous bind/unbind will throw Unbalanced pm_runtime_enable error.
> Subsequent unbind will return No such device error while bind attempt
> will return Resource temporarily unavailable error.
>
> [   47.592434] cadence-qspi 108d2000.spi: Runtime PM usage count underflow!
> [   49.592233] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128)
> [   53.232309] cadence-qspi 108d2000.spi: Runtime PM usage count underflow!
> [   55.828550] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128)
> [   57.940627] cadence-qspi 108d2000.spi: Runtime PM usage count underflow!
> [   59.912490] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128)
> [   61.876243] cadence-qspi 108d2000.spi: Runtime PM usage count underflow!
> [   61.883000] platform 108d2000.spi: Unbalanced pm_runtime_enable!
> [  532.012270] cadence-qspi 108d2000.spi: probe with driver cadence-qspi failed1
>
> Also change the clk_disable_unprepare() to clk_disable() as continuous
> bind and unbind will cause warning being thrown with inidication that
> the clock is already unprepared.
>
> Fixes: 4892b374c9b7 ("mtd: spi-nor: cadence-quadspi: Add runtime PM support")
> cc: stable@...r.kernel.org # 6.6+
> Signed-off-by: Khairul Anuar Romli <khairul.anuar.romli@...era.com>
> Reviewed-by: Matthew Gerlach <matthew.gerlach@...era.com>
> ---
Hi Khairul,
It helps the reviewers, if a revision list highlighting the changes 
between is provided under the ---.
Something like the following:

v2:
  - Description of first change since v1.
  - Description of second change since v1.

Matthew Gerlach
>   drivers/spi/spi-cadence-quadspi.c | 12 +++++++-----
>   1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
> index c90462783b3f..506a139fbd2c 100644
> --- a/drivers/spi/spi-cadence-quadspi.c
> +++ b/drivers/spi/spi-cadence-quadspi.c
> @@ -1958,10 +1958,10 @@ static int cqspi_probe(struct platform_device *pdev)
>   			goto probe_setup_failed;
>   	}
>   
> -	ret = devm_pm_runtime_enable(dev);
> -	if (ret) {
> -		if (cqspi->rx_chan)
> -			dma_release_channel(cqspi->rx_chan);
> +	pm_runtime_enable(dev);
> +
> +	if (cqspi->rx_chan) {
> +		dma_release_channel(cqspi->rx_chan);
>   		goto probe_setup_failed;
>   	}
>   
> @@ -1981,6 +1981,7 @@ static int cqspi_probe(struct platform_device *pdev)
>   	return 0;
>   probe_setup_failed:
>   	cqspi_controller_enable(cqspi, 0);
> +	pm_runtime_disable(dev);
>   probe_reset_failed:
>   	if (cqspi->is_jh7110)
>   		cqspi_jh7110_disable_clk(pdev, cqspi);
> @@ -1999,7 +2000,8 @@ static void cqspi_remove(struct platform_device *pdev)
>   	if (cqspi->rx_chan)
>   		dma_release_channel(cqspi->rx_chan);
>   
> -	clk_disable_unprepare(cqspi->clk);
> +	if (pm_runtime_get_sync(&pdev->dev) >= 0)
> +		clk_disable(cqspi->clk);
>   
>   	if (cqspi->is_jh7110)
>   		cqspi_jh7110_disable_clk(pdev, cqspi);