netdev - Re: [PATCH net-next v3 07/19] net: ravb: Move reference clock enable/disable on runtime PM APIs

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Message-ID: <80b7337b-5fc2-07bc-a05f-b583ccaac3da@omp.ru>
Date: Fri, 5 Jan 2024 22:52:20 +0300
From: Sergey Shtylyov <s.shtylyov@....ru>
To: Claudiu <claudiu.beznea@...on.dev>, <davem@...emloft.net>,
	<edumazet@...gle.com>, <kuba@...nel.org>, <pabeni@...hat.com>,
	<richardcochran@...il.com>, <p.zabel@...gutronix.de>,
	<yoshihiro.shimoda.uh@...esas.com>, <wsa+renesas@...g-engineering.com>
CC: <netdev@...r.kernel.org>, <linux-renesas-soc@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <geert+renesas@...der.be>, Claudiu Beznea
	<claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH net-next v3 07/19] net: ravb: Move reference clock
 enable/disable on runtime PM APIs

On 1/5/24 11:23 AM, Claudiu wrote:

> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> 
> Reference clock could be or not part of the power domain. If it is part of
> the power domain, the power domain takes care of propertly setting it. In
> case it is not part of the power domain and full runtime PM support is
> available in driver the clock will not be propertly disabled/enabled at
> runtime. For this, keep the prepare/unprepare operations in the driver's
> probe()/remove() functions and move the enable/disable in runtime PM
> functions.
> 
> Along with it, the other clock request operations were moved close to
> reference clock request and prepare to have all the clock requests
> specific code grouped together.
> 
> Reviewed-by: Sergey Shtylyov <s.shtylyov@....ru>

   It's not that I reviewed the squashed version of this patch...

> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> ---
> 
> Changes in v3:
> - squashed with patch 17/21 ("net: ravb: Keep clock request operations grouped
>   together") from v2
> - collected tags
> 
> Changes in v2:
> - this patch is new and follows the recommendations proposed in the
>   discussion of patch 08/13 ("net: ravb: Rely on PM domain to enable refclk")
>   from v2
> 
>  drivers/net/ethernet/renesas/ravb_main.c | 110 ++++++++++++-----------
>  1 file changed, 57 insertions(+), 53 deletions(-)
> 
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index 844ac3306e93..4673cc2faec0 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
[...]
> @@ -2697,10 +2692,37 @@ static int ravb_probe(struct platform_device *pdev)
>  		priv->num_rx_ring[RAVB_NC] = NC_RX_RING_SIZE;
>  	}
>  
> +	priv->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(priv->clk)) {
> +		error = PTR_ERR(priv->clk);
> +		goto out_reset_assert;
> +	}
> +
> +	if (info->gptp_ref_clk) {
> +		priv->gptp_clk = devm_clk_get(&pdev->dev, "gptp");
> +		if (IS_ERR(priv->gptp_clk)) {
> +			error = PTR_ERR(priv->gptp_clk);
> +			goto out_reset_assert;
> +		}
> +	}
> +
> +	priv->refclk = devm_clk_get_optional(&pdev->dev, "refclk");
> +	if (IS_ERR(priv->refclk)) {
> +		error = PTR_ERR(priv->refclk);
> +		goto out_reset_assert;
> +	}
> +	clk_prepare(priv->refclk);
> +
> +	platform_set_drvdata(pdev, ndev);

   Why exactly you had to move this line?

> +	pm_runtime_enable(&pdev->dev);
> +	error = pm_runtime_resume_and_get(&pdev->dev);
> +	if (error < 0)
> +		goto out_rpm_disable;
> +
>  	priv->addr = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
>  	if (IS_ERR(priv->addr)) {
>  		error = PTR_ERR(priv->addr);
> -		goto out_release;
> +		goto out_rpm_put;
>  	}
>  
>  	/* The Ether-specific entries in the device structure. */
[...]
> @@ -2871,8 +2872,6 @@ static int ravb_probe(struct platform_device *pdev)
>  	netdev_info(ndev, "Base address at %#x, %pM, IRQ %d.\n",
>  		    (u32)ndev->base_addr, ndev->dev_addr, ndev->irq);
>  
> -	platform_set_drvdata(pdev, ndev);

   Hm, wasn't calling it here racy?

> -
>  	return 0;
>  
>  out_napi_del:
[...]
> @@ -3060,21 +3058,27 @@ static int ravb_resume(struct device *dev)
>  	return ret;
>  }
>  
> -static int ravb_runtime_nop(struct device *dev)
> +static int ravb_runtime_suspend(struct device *dev)
>  {
> -	/* Runtime PM callback shared between ->runtime_suspend()
> -	 * and ->runtime_resume(). Simply returns success.
> -	 *
> -	 * This driver re-initializes all registers after
> -	 * pm_runtime_get_sync() anyway so there is no need
> -	 * to save and restore registers here.
> -	 */

   Perhaps even worth a separate patch to completely remove this function
which doesn't seem to make sense?

[...]

MBR, Sergey