Re: [PATCH] usb: cdns3: imx: Rework system PM to avoid duplicated operations

From: Peter Chen <peter.chen@kernel.org>
To: Shenwei Wang <shenwei.wang@nxp.com>
Cc: Pawel Laszczak <pawell@cadence.com>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Roger Quadros <rogerq@kernel.org>,
	Aswath Govindraju <a-govindraju@ti.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	imx@lists.linux.dev, Frank Li <frank.li@nxp.com>
Subject: Re: [PATCH] usb: cdns3: imx: Rework system PM to avoid duplicated operations
Date: Mon, 5 Jun 2023 07:17:11 +0800	[thread overview]
Message-ID: <20230604231711.GD258497@nchen-desktop> (raw)
In-Reply-To: <20230523184412.204582-1-shenwei.wang@nxp.com>

On 23-05-23 13:44:12, Shenwei Wang wrote:
> The current implementation uses the same callbacks for system PM and
> runtime PM suspend/resume without any state checking. This can cause the
> clocks to be prepared/unprepared twice, leading to kernel warning issues.
> 
> This patch resolves the double prepare/unprepare issues by separating the
> runtime PM and system PM handling.
> 
> Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
> Reviewed-by: Frank Li <frank.li@nxp.com>
> ---
>  drivers/usb/cdns3/cdns3-imx.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/cdns3/cdns3-imx.c b/drivers/usb/cdns3/cdns3-imx.c
> index 59860d1753fd..1c6bc6036c15 100644
> --- a/drivers/usb/cdns3/cdns3-imx.c
> +++ b/drivers/usb/cdns3/cdns3-imx.c
> @@ -375,14 +375,22 @@ static inline bool cdns_imx_is_power_lost(struct cdns_imx *data)
>  		return false;
>  }
>  
> +static int __maybe_unused cdns_imx_system_suspend(struct device *dev)
> +{
> +	pm_runtime_put_sync(dev);
> +	return 0;
> +}
> +
>  static int __maybe_unused cdns_imx_system_resume(struct device *dev)
>  {
>  	struct cdns_imx *data = dev_get_drvdata(dev);
>  	int ret;
>  
> -	ret = cdns_imx_resume(dev);
> -	if (ret)
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret < 0) {
> +		dev_err(dev, "Could not get runtime PM.\n");
>  		return ret;
> +	}
>  
>  	if (cdns_imx_is_power_lost(data)) {
>  		dev_dbg(dev, "resume from power lost\n");
> @@ -405,7 +413,7 @@ static int cdns_imx_platform_suspend(struct device *dev,
>  
>  static const struct dev_pm_ops cdns_imx_pm_ops = {
>  	SET_RUNTIME_PM_OPS(cdns_imx_suspend, cdns_imx_resume, NULL)
> -	SET_SYSTEM_SLEEP_PM_OPS(cdns_imx_suspend, cdns_imx_system_resume)
> +	SET_SYSTEM_SLEEP_PM_OPS(cdns_imx_system_suspend, cdns_imx_system_resume)
>  };
>  
>  static const struct of_device_id cdns_imx_of_match[] = {
> -- 
> 2.34.1
> 

Acked-by: Peter Chen <peter.chen@kernel.org>

-- 

Thanks,
Peter Chen