linux-kernel - Re: [PATCH] IIO: ADC: stm32-dfsdm: avoid unused-variable warning

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Message-ID: <20180114120716.320526c1@archlinux>
Date:   Sun, 14 Jan 2018 12:07:16 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Arnaud Pouliquen <arnaud.pouliquen@...com>
Cc:     Robin Murphy <robin.murphy@....com>, Arnd Bergmann <arnd@...db.de>,
        Mark Brown <broonie@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Hartmut Knaack <knaack.h@....de>,
        Alexandre Torgue <alexandre.torgue@...com>
Subject: Re: [PATCH] IIO: ADC: stm32-dfsdm: avoid unused-variable warning

On Thu, 11 Jan 2018 18:38:49 +0100
Arnaud Pouliquen <arnaud.pouliquen@...com> wrote:

> On 01/11/2018 03:27 PM, Robin Murphy wrote:
> > On 11/01/18 10:34, Arnd Bergmann wrote:  
> >> Building with CONFIG_OF disabled produces a compiler warning:
> >>
> >> drivers/iio/adc/stm32-dfsdm-core.c: In function 'stm32_dfsdm_probe':
> >> drivers/iio/adc/stm32-dfsdm-core.c:245:22: error: unused variable
> >> 'pnode' [-Werror=unused-variable]
> >>
> >> This removes the variable and open-codes it in the only place
> >> it gets used to avoid that warning.
> >>
> >> Fixes: bed73904e76f ("IIO: ADC: add stm32 DFSDM core support")
> >> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> >> ---
> >>   drivers/iio/adc/stm32-dfsdm-core.c | 3 +--
> >>   1 file changed, 1 insertion(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/iio/adc/stm32-dfsdm-core.c
> >> b/drivers/iio/adc/stm32-dfsdm-core.c
> >> index 72427414db7f..6cd655f8239b 100644
> >> --- a/drivers/iio/adc/stm32-dfsdm-core.c
> >> +++ b/drivers/iio/adc/stm32-dfsdm-core.c
> >> @@ -242,7 +242,6 @@ MODULE_DEVICE_TABLE(of, stm32_dfsdm_of_match);
> >>   static int stm32_dfsdm_probe(struct platform_device *pdev)
> >>   {
> >>       struct dfsdm_priv *priv;
> >> -    struct device_node *pnode = pdev->dev.of_node;
> >>       const struct of_device_id *of_id;
> >>       const struct stm32_dfsdm_dev_data *dev_data;
> >>       struct stm32_dfsdm *dfsdm;
> >> @@ -254,7 +253,7 @@ static int stm32_dfsdm_probe(struct
> >> platform_device *pdev)
> >>         priv->pdev = pdev;
> >>   -    of_id = of_match_node(stm32_dfsdm_of_match, pnode);
> >> +    of_id = of_match_node(stm32_dfsdm_of_match, pdev->dev.of_node);
> >>       if (!of_id->data) {
> >>           dev_err(&pdev->dev, "Data associated to device is missing\n");
> >>           return -EINVAL;  
> > 
> > FWIW, it looks like this whole lot could be cleaned up by using
> > of_device_get_match_data().
> >   
> Right, and test of the return now seems to me an overprotection as data
> structure is defined in the driver...
> 
> Same optimization could be applied to stm32_dfsdm_adc_probe function.
> 
> Here is the patch I tested:

This looks like a good solution to me.

Acked-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

(given this should probably go on Mark's immutable branch).

Jonathan

> 
> ---
>  drivers/iio/adc/stm32-dfsdm-adc.c  | 9 +--------
>  drivers/iio/adc/stm32-dfsdm-core.c | 9 +--------
>  2 files changed, 2 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c
> b/drivers/iio/adc/stm32-dfsdm-adc.c
> index b03ca3f..01836c9 100644
> --- a/drivers/iio/adc/stm32-dfsdm-adc.c
> +++ b/drivers/iio/adc/stm32-dfsdm-adc.c
> @@ -1087,18 +1087,11 @@ static int stm32_dfsdm_adc_probe(struct
> platform_device *pdev)
>  	struct device_node *np = dev->of_node;
>  	const struct stm32_dfsdm_dev_data *dev_data;
>  	struct iio_dev *iio;
> -	const struct of_device_id *of_id;
>  	char *name;
>  	int ret, irq, val;
> 
> -	of_id = of_match_node(stm32_dfsdm_adc_match, np);
> -	if (!of_id->data) {
> -		dev_err(&pdev->dev, "Data associated to device is missing\n");
> -		return -EINVAL;
> -	}
> -
> -	dev_data = (const struct stm32_dfsdm_dev_data *)of_id->data;
> 
> +	dev_data = of_device_get_match_data(dev);
>  	iio = devm_iio_device_alloc(dev, sizeof(*adc));
>  	if (IS_ERR(iio)) {
>  		dev_err(dev, "%s: Failed to allocate IIO\n", __func__);
> diff --git a/drivers/iio/adc/stm32-dfsdm-core.c
> b/drivers/iio/adc/stm32-dfsdm-core.c
> index 7242741..6290332 100644
> --- a/drivers/iio/adc/stm32-dfsdm-core.c
> +++ b/drivers/iio/adc/stm32-dfsdm-core.c
> @@ -242,8 +242,6 @@ MODULE_DEVICE_TABLE(of, stm32_dfsdm_of_match);
>  static int stm32_dfsdm_probe(struct platform_device *pdev)
>  {
>  	struct dfsdm_priv *priv;
> -	struct device_node *pnode = pdev->dev.of_node;
> -	const struct of_device_id *of_id;
>  	const struct stm32_dfsdm_dev_data *dev_data;
>  	struct stm32_dfsdm *dfsdm;
>  	int ret;
> @@ -254,13 +252,8 @@ static int stm32_dfsdm_probe(struct platform_device
> *pdev)
> 
>  	priv->pdev = pdev;
> 
> -	of_id = of_match_node(stm32_dfsdm_of_match, pnode);
> -	if (!of_id->data) {
> -		dev_err(&pdev->dev, "Data associated to device is missing\n");
> -		return -EINVAL;
> -	}
> +	dev_data = of_device_get_match_data(&pdev->dev);
> 
> -	dev_data = (const struct stm32_dfsdm_dev_data *)of_id->data;
>  	dfsdm = &priv->dfsdm;
>  	dfsdm->fl_list = devm_kcalloc(&pdev->dev, dev_data->num_filters,
>  				      sizeof(*dfsdm->fl_list), GFP_KERNEL);