Re: [PATCH] V3-can: mcp251x: add error handling for power enable in open and resume

[Marc Kleine-Budde]

Hello Wenyuan Li,

the patch looks almost perfect, good work! Some minor nitpicks inside.

A small tip for the v4, use "git send-email -v4", so that the "v4" goes
to the correct place in the subject. For you next patches have a look at
the great tool b4: https://b4.docs.kernel.org/en/latest/

On 15.03.2026 23:14:45, Wenyuan Li wrote:
> Add missing error handling for mcp251x_power_enable() calls in both
> mcp251x_open() and mcp251x_can_resume() functions.
>
> In mcp251x_open(), if power enable fails, the driver should not continue
> with device initialization. Add proper error checking and jump to
> existing out_close label.
>
> In mcp251x_can_resume(), if power enable fails during system resume,
> propagate the error to PM framework and log the error with dev_err()
> for debugging.
>
> This ensures the driver properly handles power control failures and
> maintains correct device state.
> Signed-off-by: Wenyuan Li <2063309626@xxxxxx>
>
> Add missing error handling for mcp251x_power_enable() calls in both
> mcp251x_open() and mcp251x_can_resume() functions.
>
> In mcp251x_open(), if power enable fails, jump to error path to close
> candev without attempting to disable power again.
>
> In mcp251x_can_resume(), properly check return values of power enable
> calls for both power and transceiver regulators. If any fails, return
> the error code to the PM framework and log the failure.
>
> This ensures the driver properly handles power control failures and
> maintains correct device state.
>
> Signed-off-by: Wenyuan Li <2063309626@xxxxxx>
> ---
>  drivers/net/can/spi/mcp251x.c | 33 +++++++++++++++++++++++++++------
>  1 file changed, 27 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
> index bb7782582f40..6e17133a4e03 100644
> --- a/drivers/net/can/spi/mcp251x.c
> +++ b/drivers/net/can/spi/mcp251x.c
> @@ -1225,7 +1225,11 @@ static int mcp251x_open(struct net_device *net)
>  	}
>
>  	mutex_lock(&priv->mcp_lock);
> -	mcp251x_power_enable(priv->transceiver, 1);
> +	ret = mcp251x_power_enable(priv->transceiver, 1);
> +	if (ret) {
> +		dev_err(&spi->dev, "failed to enable transceiver power: %pe\n", ERR_PTR(ret));
> +		goto out_close_candev;
> +	}
>
>  	priv->force_quit = 0;
>  	priv->tx_skb = NULL;
> @@ -1272,6 +1276,7 @@ static int mcp251x_open(struct net_device *net)
>  	mcp251x_hw_sleep(spi);
>  out_close:
>  	mcp251x_power_enable(priv->transceiver, 0);
> +out_close_candev:
>  	close_candev(net);
>  	mutex_unlock(&priv->mcp_lock);
>  	if (release_irq)
> @@ -1516,11 +1521,26 @@ static int __maybe_unused mcp251x_can_resume(struct device *dev)
>  {
>  	struct spi_device *spi = to_spi_device(dev);
>  	struct mcp251x_priv *priv = spi_get_drvdata(spi);
> +	int ret = 0;
>
> -	if (priv->after_suspend & AFTER_SUSPEND_POWER)
> -		mcp251x_power_enable(priv->power, 1);
> -	if (priv->after_suspend & AFTER_SUSPEND_UP)
> -		mcp251x_power_enable(priv->transceiver, 1);
> +	if (priv->after_suspend & AFTER_SUSPEND_POWER) {
> +		ret = mcp251x_power_enable(priv->power, 1);
> +		if (ret) {
> +			dev_err(dev, "Failed to restore power: %pe\n", ERR_PTR(ret));
> +			goto out;

As we don't do any cleanups you can do a "return ret;" instead of the
goto.

Please use "failed" or "Failed" consistently in the patch.

> +		}
> +	}
> +
> +	if (priv->after_suspend & AFTER_SUSPEND_UP) {
> +		ret = mcp251x_power_enable(priv->transceiver, 1);
> +		if (ret) {
> +			dev_err(dev, "Failed to restore transceiver power: %pe\n", ERR_PTR(ret));
> +			/* If the transceiver fails to be enabled, turn off the power that has been enabled.*/

IMHO that comment states the obvious, please remove.

> +			if (priv->after_suspend & AFTER_SUSPEND_POWER)
> +				mcp251x_power_enable(priv->power, 0);
> +			goto out;
> +		}
> +	}
>
>  	if (priv->after_suspend & (AFTER_SUSPEND_POWER | AFTER_SUSPEND_UP))
>  		queue_work(priv->wq, &priv->restart_work);
> @@ -1529,7 +1549,8 @@ static int __maybe_unused mcp251x_can_resume(struct device *dev)
>
>  	priv->force_quit = 0;
>  	enable_irq(spi->irq);
> -	return 0;
> +out:
> +	return ret;
>  }
>
>  static SIMPLE_DEV_PM_OPS(mcp251x_can_pm_ops, mcp251x_can_suspend,

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
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