linux-kernel - Re: [PATCH] [v2] spi: spi-zynqmp-gqspi: Fix runtime PM imbalance in zynqmp_qspi

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Date:   Thu, 15 Apr 2021 09:21:58 +0800
From:   wqyoung <quanyang.wang@...driver.com>
To:     Dinghao Liu <dinghao.liu@....edu.cn>
Cc:     kjlu@....edu, Mark Brown <broonie@...nel.org>,
        Michal Simek <michal.simek@...inx.com>,
        linux-spi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [v2] spi: spi-zynqmp-gqspi: Fix runtime PM imbalance in
 zynqmp_qspi_probe

Hi Dinghao,
On Mon, Apr 12, 2021 at 03:31:54PM +0800, Dinghao Liu wrote:
> There is a PM usage counter decrement after zynqmp_qspi_init_hw()
> without any refcount increment, which leads to refcount leak.Add
> a refcount increment to balance the refcount. Also set
> auto_runtime_pm to resume suspended spi controller.
> 
> Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
> ---
> changelog:
> 
> v2: - Add a refcount increment to fix refcout leak instead of the
>       refcount decrement on error.
>       Set ctlr->auto_runtime_pm = true.
> ---
>  drivers/spi/spi-zynqmp-gqspi.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
> index c8fa6ee18ae7..8b21c7b0e7eb 100644
> --- a/drivers/spi/spi-zynqmp-gqspi.c
> +++ b/drivers/spi/spi-zynqmp-gqspi.c
> @@ -1160,6 +1160,7 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
>  	pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
>  	pm_runtime_set_active(&pdev->dev);
>  	pm_runtime_enable(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
Please check the return value here, if ret is "< 0", goto error label,
and a pm_runtime_put_sync is needed in error label
>  	/* QSPI controller initializations */
>  	zynqmp_qspi_init_hw(xqspi);
>  
> @@ -1187,6 +1188,7 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
>  	ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD |
>  			    SPI_TX_DUAL | SPI_TX_QUAD;
>  	ctlr->dev.of_node = np;
> +	ctlr->auto_runtime_pm = true;
>  
>  	ret = devm_spi_register_controller(&pdev->dev, ctlr);
>  	if (ret) {
These 2 function
     pm_runtime_mark_last_busy(&pdev->dev);
      pm_runtime_put_autosuspend(&pdev->dev);
are the last operations in probe function since if they runs,
spi_controller will enter suspend state and disable clks after 3s
passing. So please move them just before "return 0".

And would you please cc me when you send V3? I am preparing to send a patch series
to fix clk and suspend/resume issues which bases on the pm_runtime issue.

Thanks,
Quanyang
> -- 
> 2.17.1
>