Subject: Re: [PATCH v2] iio: stm32-dfsdm-adc: remove usage of iio_priv_to_dev() helper

From: Jonathan Cameron <[email-masked]>
Date: Sun, 31 May 2020 15:45:35 +0100

On Mon, 25 May 2020 11:26:48 +0300
Alexandru Ardelean <[email-masked]> wrote:

> We may want to get rid of the iio_priv_to_dev() helper. The reason is that
> we will hide some of the members of the iio_dev structure (to prevent
> drivers from accessing them directly), and that will also mean hiding the
> implementation of the iio_priv_to_dev() helper inside the IIO core.
> 
> Hiding the implementation of iio_priv_to_dev() implies that some fast-paths
> may not be fast anymore, so a general idea is to try to get rid of the
> iio_priv_to_dev() altogether.
> The iio_priv() helper won't be affected by the rework, as the iio_dev
> struct will keep a reference to the private information.
> 
> For this driver, not using iio_priv_to_dev(), means reworking some paths to
> pass the iio device and using iio_priv() to access the private information.
> 
> Signed-off-by: Alexandru Ardelean <[email-masked]>
Looks great.  Will let it sit a little longer on list for others to review
though.

Thanks,

Jonathan

> ---
> 
> Changelog v1 -> v2:
> * changed some paths to pass a reference to ref to iio device and access
>   private state-struct via iio_priv()
> 
>  drivers/iio/adc/stm32-dfsdm-adc.c | 65 ++++++++++++++++---------------
>  1 file changed, 33 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
> index 76a60d93fe23..03dfc0b6ba98 100644
> --- a/drivers/iio/adc/stm32-dfsdm-adc.c
> +++ b/drivers/iio/adc/stm32-dfsdm-adc.c
> @@ -330,9 +330,9 @@ static int stm32_dfsdm_compute_all_osrs(struct iio_dev *indio_dev,
>  	return 0;
>  }
>  
> -static int stm32_dfsdm_start_channel(struct stm32_dfsdm_adc *adc)
> +static int stm32_dfsdm_start_channel(struct iio_dev *indio_dev)
>  {
> -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  	struct regmap *regmap = adc->dfsdm->regmap;
>  	const struct iio_chan_spec *chan;
>  	unsigned int bit;
> @@ -350,9 +350,9 @@ static int stm32_dfsdm_start_channel(struct stm32_dfsdm_adc *adc)
>  	return 0;
>  }
>  
> -static void stm32_dfsdm_stop_channel(struct stm32_dfsdm_adc *adc)
> +static void stm32_dfsdm_stop_channel(struct iio_dev *indio_dev)
>  {
> -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  	struct regmap *regmap = adc->dfsdm->regmap;
>  	const struct iio_chan_spec *chan;
>  	unsigned int bit;
> @@ -418,11 +418,11 @@ static void stm32_dfsdm_stop_filter(struct stm32_dfsdm *dfsdm,
>  			   DFSDM_CR1_DFEN_MASK, DFSDM_CR1_DFEN(0));
>  }
>  
> -static int stm32_dfsdm_filter_set_trig(struct stm32_dfsdm_adc *adc,
> +static int stm32_dfsdm_filter_set_trig(struct iio_dev *indio_dev,
>  				       unsigned int fl_id,
>  				       struct iio_trigger *trig)
>  {
> -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  	struct regmap *regmap = adc->dfsdm->regmap;
>  	u32 jextsel = 0, jexten = STM32_DFSDM_JEXTEN_DISABLED;
>  	int ret;
> @@ -447,11 +447,11 @@ static int stm32_dfsdm_filter_set_trig(struct stm32_dfsdm_adc *adc,
>  	return 0;
>  }
>  
> -static int stm32_dfsdm_channels_configure(struct stm32_dfsdm_adc *adc,
> +static int stm32_dfsdm_channels_configure(struct iio_dev *indio_dev,
>  					  unsigned int fl_id,
>  					  struct iio_trigger *trig)
>  {
> -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  	struct regmap *regmap = adc->dfsdm->regmap;
>  	struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[fl_id];
>  	struct stm32_dfsdm_filter_osr *flo = &fl->flo[0];
> @@ -491,11 +491,11 @@ static int stm32_dfsdm_channels_configure(struct stm32_dfsdm_adc *adc,
>  	return 0;
>  }
>  
> -static int stm32_dfsdm_filter_configure(struct stm32_dfsdm_adc *adc,
> +static int stm32_dfsdm_filter_configure(struct iio_dev *indio_dev,
>  					unsigned int fl_id,
>  					struct iio_trigger *trig)
>  {
> -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  	struct regmap *regmap = adc->dfsdm->regmap;
>  	struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[fl_id];
>  	struct stm32_dfsdm_filter_osr *flo = &fl->flo[fl->fast];
> @@ -521,7 +521,7 @@ static int stm32_dfsdm_filter_configure(struct stm32_dfsdm_adc *adc,
>  	if (ret)
>  		return ret;
>  
> -	ret = stm32_dfsdm_filter_set_trig(adc, fl_id, trig);
> +	ret = stm32_dfsdm_filter_set_trig(indio_dev, fl_id, trig);
>  	if (ret)
>  		return ret;
>  
> @@ -729,21 +729,22 @@ static ssize_t dfsdm_adc_audio_set_spiclk(struct iio_dev *indio_dev,
>  	return len;
>  }
>  
> -static int stm32_dfsdm_start_conv(struct stm32_dfsdm_adc *adc,
> +static int stm32_dfsdm_start_conv(struct iio_dev *indio_dev,
>  				  struct iio_trigger *trig)
>  {
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  	struct regmap *regmap = adc->dfsdm->regmap;
>  	int ret;
>  
> -	ret = stm32_dfsdm_channels_configure(adc, adc->fl_id, trig);
> +	ret = stm32_dfsdm_channels_configure(indio_dev, adc->fl_id, trig);
>  	if (ret < 0)
>  		return ret;
>  
> -	ret = stm32_dfsdm_start_channel(adc);
> +	ret = stm32_dfsdm_start_channel(indio_dev);
>  	if (ret < 0)
>  		return ret;
>  
> -	ret = stm32_dfsdm_filter_configure(adc, adc->fl_id, trig);
> +	ret = stm32_dfsdm_filter_configure(indio_dev, adc->fl_id, trig);
>  	if (ret < 0)
>  		goto stop_channels;
>  
> @@ -757,13 +758,14 @@ static int stm32_dfsdm_start_conv(struct stm32_dfsdm_adc *adc,
>  	regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
>  			   DFSDM_CR1_CFG_MASK, 0);
>  stop_channels:
> -	stm32_dfsdm_stop_channel(adc);
> +	stm32_dfsdm_stop_channel(indio_dev);
>  
>  	return ret;
>  }
>  
> -static void stm32_dfsdm_stop_conv(struct stm32_dfsdm_adc *adc)
> +static void stm32_dfsdm_stop_conv(struct iio_dev *indio_dev)
>  {
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  	struct regmap *regmap = adc->dfsdm->regmap;
>  
>  	stm32_dfsdm_stop_filter(adc->dfsdm, adc->fl_id);
> @@ -771,7 +773,7 @@ static void stm32_dfsdm_stop_conv(struct stm32_dfsdm_adc *adc)
>  	regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
>  			   DFSDM_CR1_CFG_MASK, 0);
>  
> -	stm32_dfsdm_stop_channel(adc);
> +	stm32_dfsdm_stop_channel(indio_dev);
>  }
>  
>  static int stm32_dfsdm_set_watermark(struct iio_dev *indio_dev,
> @@ -1017,7 +1019,7 @@ static int __stm32_dfsdm_postenable(struct iio_dev *indio_dev)
>  		goto stop_dfsdm;
>  	}
>  
> -	ret = stm32_dfsdm_start_conv(adc, indio_dev->trig);
> +	ret = stm32_dfsdm_start_conv(indio_dev, indio_dev->trig);
>  	if (ret) {
>  		dev_err(&indio_dev->dev, "Can't start conversion\n");
>  		goto err_stop_dma;
> @@ -1063,7 +1065,7 @@ static void __stm32_dfsdm_predisable(struct iio_dev *indio_dev)
>  {
>  	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  
> -	stm32_dfsdm_stop_conv(adc);
> +	stm32_dfsdm_stop_conv(indio_dev);
>  
>  	stm32_dfsdm_adc_dma_stop(indio_dev);
>  
> @@ -1159,7 +1161,7 @@ static int stm32_dfsdm_single_conv(struct iio_dev *indio_dev,
>  
>  	adc->nconv = 1;
>  	adc->smask = BIT(chan->scan_index);
> -	ret = stm32_dfsdm_start_conv(adc, NULL);
> +	ret = stm32_dfsdm_start_conv(indio_dev, NULL);
>  	if (ret < 0) {
>  		regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
>  				   DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(0));
> @@ -1180,7 +1182,7 @@ static int stm32_dfsdm_single_conv(struct iio_dev *indio_dev,
>  	else
>  		ret = IIO_VAL_INT;
>  
> -	stm32_dfsdm_stop_conv(adc);
> +	stm32_dfsdm_stop_conv(indio_dev);
>  
>  	stm32_dfsdm_process_data(adc, res);
>  
> @@ -1313,8 +1315,8 @@ static const struct iio_info stm32_dfsdm_info_adc = {
>  
>  static irqreturn_t stm32_dfsdm_irq(int irq, void *arg)
>  {
> -	struct stm32_dfsdm_adc *adc = arg;
> -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> +	struct iio_dev *indio_dev = arg;
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  	struct regmap *regmap = adc->dfsdm->regmap;
>  	unsigned int status, int_en;
>  
> @@ -1574,7 +1576,7 @@ static int stm32_dfsdm_adc_probe(struct platform_device *pdev)
>  	iio->dev.of_node = np;
>  	iio->modes = INDIO_DIRECT_MODE;
>  
> -	platform_set_drvdata(pdev, adc);
> +	platform_set_drvdata(pdev, iio);
>  
>  	ret = of_property_read_u32(dev->of_node, "reg", &adc->fl_id);
>  	if (ret != 0 || adc->fl_id >= adc->dfsdm->num_fls) {
> @@ -1603,7 +1605,7 @@ static int stm32_dfsdm_adc_probe(struct platform_device *pdev)
>  		return irq;
>  
>  	ret = devm_request_irq(dev, irq, stm32_dfsdm_irq,
> -			       0, pdev->name, adc);
> +			       0, pdev->name, iio);
>  	if (ret < 0) {
>  		dev_err(dev, "Failed to request IRQ\n");
>  		return ret;
> @@ -1650,8 +1652,8 @@ static int stm32_dfsdm_adc_probe(struct platform_device *pdev)
>  
>  static int stm32_dfsdm_adc_remove(struct platform_device *pdev)
>  {
> -	struct stm32_dfsdm_adc *adc = platform_get_drvdata(pdev);
> -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  
>  	if (adc->dev_data->type == DFSDM_AUDIO)
>  		of_platform_depopulate(&pdev->dev);
> @@ -1663,8 +1665,7 @@ static int stm32_dfsdm_adc_remove(struct platform_device *pdev)
>  
>  static int __maybe_unused stm32_dfsdm_adc_suspend(struct device *dev)
>  {
> -	struct stm32_dfsdm_adc *adc = dev_get_drvdata(dev);
> -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>  
>  	if (iio_buffer_enabled(indio_dev))
>  		__stm32_dfsdm_predisable(indio_dev);
> @@ -1674,8 +1675,8 @@ static int __maybe_unused stm32_dfsdm_adc_suspend(struct device *dev)
>  
>  static int __maybe_unused stm32_dfsdm_adc_resume(struct device *dev)
>  {
> -	struct stm32_dfsdm_adc *adc = dev_get_drvdata(dev);
> -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>  	const struct iio_chan_spec *chan;
>  	struct stm32_dfsdm_channel *ch;
>  	int i, ret;

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