linux-kernel - Re: [PATCH v2] can: tcan4x5x: Turn on the power before parsing the config

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Date:   Thu, 2 Jan 2020 12:11:52 +0100
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     Dan Murphy <dmurphy@...com>
Cc:     linux-can@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v2] can: tcan4x5x: Turn on the power before parsing the
 config

On 12/10/19 5:32 PM, Dan Murphy wrote:
> The parse config function now performs action on the device either
> reading or writing and a reset.  If the regulator is managed it needs
> to be turned on.  So turn on the regulator if available if the parsing
> fails then turn off the regulator.
> 
> Fixes: a5235f3c7c23 ("can: tcan45x: Make wake-up GPIO an optional GPIO")
> Signed-off-by: Dan Murphy <dmurphy@...com>
> ---
> 
> v2 - Added error handling and moved regulator_get to probe
> 
>  drivers/net/can/m_can/tcan4x5x.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/can/m_can/tcan4x5x.c b/drivers/net/can/m_can/tcan4x5x.c
> index 4e1789ea2bc3..ddf7db498241 100644
> --- a/drivers/net/can/m_can/tcan4x5x.c
> +++ b/drivers/net/can/m_can/tcan4x5x.c
> @@ -374,11 +374,6 @@ static int tcan4x5x_parse_config(struct m_can_classdev *cdev)
>  	if (IS_ERR(tcan4x5x->device_state_gpio))
>  		tcan4x5x->device_state_gpio = NULL;
>  
> -	tcan4x5x->power = devm_regulator_get_optional(cdev->dev,
> -						      "vsup");
> -	if (PTR_ERR(tcan4x5x->power) == -EPROBE_DEFER)
> -		return -EPROBE_DEFER;
> -
>  	return 0;
>  }
>  
> @@ -412,6 +407,12 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
>  	if (!priv)
>  		return -ENOMEM;
>  
> +	priv->power = devm_regulator_get_optional(&spi->dev, "vsup");
> +	if (PTR_ERR(priv->power) == -EPROBE_DEFER)
> +		return -EPROBE_DEFER;
> +	else
> +		priv->power = NULL;
> +

BTW: you are leaking the netdev allocated with m_can_class_allocate_dev().

In order to fix this:

- introduce a m_can_class_free_dev() function that calls the
  free_candev().
- fix error path in tcan4x5x_can_probe() and m_can_plat_probe() by
  adding the missing m_can_class_free_dev()
- remove the free_candev() from the error path in m_can_class_register()
  it makes no sense that this function free a ressource it has not
  allocated
- remove the free_candev() from m_can_class_unregister()
  it makes no sense that this function free a ressource it has not
  allocated
- add needed m_can_class_free_dev() to tcan4x5x_can_remove() and
  m_can_plat_remove()

Marc

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



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