netdev - Re: [PATCH v5] can: Convert to runtime

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Message-ID: <54B4FCB5.6040904@pengutronix.de>
Date:	Tue, 13 Jan 2015 12:08:37 +0100
From:	Marc Kleine-Budde <mkl@...gutronix.de>
To:	Sören Brinkmann <soren.brinkmann@...inx.com>,
	Kedareswara rao Appana <appana.durga.rao@...inx.com>
CC:	wg@...ndegger.com, michal.simek@...inx.com,
	grant.likely@...aro.org, robh+dt@...nel.org,
	linux-can@...r.kernel.org, netdev@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org,
	Kedareswara rao Appana <appanad@...inx.com>
Subject: Re: [PATCH v5] can: Convert to runtime_pm

On 01/12/2015 07:45 PM, Sören Brinkmann wrote:
> On Mon, 2015-01-12 at 08:34PM +0530, Kedareswara rao Appana wrote:
>> Instead of enabling/disabling clocks at several locations in the driver,
>> Use the runtime_pm framework. This consolidates the actions for runtime PM
>> In the appropriate callbacks and makes the driver more readable and mantainable.
>>
>> Signed-off-by: Soren Brinkmann <soren.brinkmann@...inx.com>
>> Signed-off-by: Kedareswara rao Appana <appanad@...inx.com>
>> ---
>> Changes for v5:
>>  - Updated with the review comments.
>>    Updated the remove fuction to use runtime_pm.
>> Chnages for v4:
>>  - Updated with the review comments.
>> Changes for v3:
>>   - Converted the driver to use runtime_pm.
>> Changes for v2:
>>   - Removed the struct platform_device* from suspend/resume
>>     as suggest by Lothar.
>>
>>  drivers/net/can/xilinx_can.c |  157 ++++++++++++++++++++++++++++-------------
>>  1 files changed, 107 insertions(+), 50 deletions(-)
> [..]
>> +static int __maybe_unused xcan_runtime_resume(struct device *dev)
>>  {
>> -	struct platform_device *pdev = dev_get_drvdata(dev);
>> -	struct net_device *ndev = platform_get_drvdata(pdev);
>> +	struct net_device *ndev = dev_get_drvdata(dev);
>>  	struct xcan_priv *priv = netdev_priv(ndev);
>>  	int ret;
>> +	u32 isr, status;
>>  
>>  	ret = clk_enable(priv->bus_clk);
>>  	if (ret) {
>> @@ -1014,15 +1030,28 @@ static int __maybe_unused xcan_resume(struct device *dev)
>>  	ret = clk_enable(priv->can_clk);
>>  	if (ret) {
>>  		dev_err(dev, "Cannot enable clock.\n");
>> -		clk_disable_unprepare(priv->bus_clk);
>> +		clk_disable(priv->bus_clk);
> [...]
>> @@ -1173,12 +1219,23 @@ static int xcan_remove(struct platform_device *pdev)
>>  {
>>  	struct net_device *ndev = platform_get_drvdata(pdev);
>>  	struct xcan_priv *priv = netdev_priv(ndev);
>> +	int ret;
>> +
>> +	ret = pm_runtime_get_sync(&pdev->dev);
>> +	if (ret < 0) {
>> +		netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n",
>> +				__func__, ret);
>> +		return ret;
>> +	}
>>  
>>  	if (set_reset_mode(ndev) < 0)
>>  		netdev_err(ndev, "mode resetting failed!\n");
>>  
>>  	unregister_candev(ndev);
>> +	pm_runtime_disable(&pdev->dev);
>>  	netif_napi_del(&priv->napi);
>> +	clk_disable_unprepare(priv->bus_clk);
>> +	clk_disable_unprepare(priv->can_clk);
> 
> Shouldn't pretty much all these occurrences of clk_disable/enable
> disappear? This should all be handled by the runtime_pm framework now.

We have:
- clk_prepare_enable() in probe
- clk_disable_unprepare() in remove
- clk_enable() in runtime_resume
- clk_disable() in runtime_suspend

Which is, as far as I understand the right way to do it. Maybe
Kedareswara can post the clock debug output again with this patch
iteration. Have I missed something?

regards,
Marc
-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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