Date:   Sun, 31 May 2020 15:47:29 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Fabrice Gasnier <fabrice.gasnier@...com>
Cc:     Alexandru Ardelean <alexandru.ardelean@...log.com>,
        <linux-iio@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <mcoquelin.stm32@...il.com>,
        <alexandre.torgue@...com>, <olivier.moysan@...com>
Subject: Re: [PATCH v3] iio: stm32-adc: remove usage of iio_priv_to_dev()
 helper

On Tue, 26 May 2020 17:46:41 +0200
Fabrice Gasnier <fabrice.gasnier@...com> wrote:

> On 5/26/20 3:44 PM, Alexandru Ardelean 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 <alexandru.ardelean@...log.com>
> > ---
> > 
> > Changelog v2 -> v3:
> > - update doc-strings; warnings show-up during build with W=1 arg
> > 
> > Changelog v1 -> v2:
> > - converted to pass reference to IIO device in function hooks (vs
> >   reference
> >   to adc private data)
> > 
> >  drivers/iio/adc/stm32-adc.c | 118 +++++++++++++++++++-----------------
> >  1 file changed, 63 insertions(+), 55 deletions(-)  
> 
> Hi Alexandru,
> 
> Acked-by: Fabrice Gasnier <fabrice.gasnier@...com>

Applied to the togreg branch of iio.git and pushed out as testing for the
autobuilders to poke at it.

Thanks,

Jonathan

> 
> Thanks,
> Fabrice
> 
> > 
> > diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> > index ae622ee6d08c..1dd97ec5571c 100644
> > --- a/drivers/iio/adc/stm32-adc.c
> > +++ b/drivers/iio/adc/stm32-adc.c
> > @@ -162,10 +162,10 @@ struct stm32_adc_cfg {
> >  	struct stm32_adc_trig_info	*trigs;
> >  	bool clk_required;
> >  	bool has_vregready;
> > -	int (*prepare)(struct stm32_adc *);
> > -	void (*start_conv)(struct stm32_adc *, bool dma);
> > -	void (*stop_conv)(struct stm32_adc *);
> > -	void (*unprepare)(struct stm32_adc *);
> > +	int (*prepare)(struct iio_dev *);
> > +	void (*start_conv)(struct iio_dev *, bool dma);
> > +	void (*stop_conv)(struct iio_dev *);
> > +	void (*unprepare)(struct iio_dev *);
> >  	const unsigned int *smp_cycles;
> >  };
> >  
> > @@ -538,10 +538,11 @@ static void stm32_adc_set_res(struct stm32_adc *adc)
> >  
> >  static int stm32_adc_hw_stop(struct device *dev)
> >  {
> > -	struct stm32_adc *adc = dev_get_drvdata(dev);
> > +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  
> >  	if (adc->cfg->unprepare)
> > -		adc->cfg->unprepare(adc);
> > +		adc->cfg->unprepare(indio_dev);
> >  
> >  	if (adc->clk)
> >  		clk_disable_unprepare(adc->clk);
> > @@ -551,7 +552,8 @@ static int stm32_adc_hw_stop(struct device *dev)
> >  
> >  static int stm32_adc_hw_start(struct device *dev)
> >  {
> > -	struct stm32_adc *adc = dev_get_drvdata(dev);
> > +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	int ret;
> >  
> >  	if (adc->clk) {
> > @@ -563,7 +565,7 @@ static int stm32_adc_hw_start(struct device *dev)
> >  	stm32_adc_set_res(adc);
> >  
> >  	if (adc->cfg->prepare) {
> > -		ret = adc->cfg->prepare(adc);
> > +		ret = adc->cfg->prepare(indio_dev);
> >  		if (ret)
> >  			goto err_clk_dis;
> >  	}
> > @@ -579,7 +581,7 @@ static int stm32_adc_hw_start(struct device *dev)
> >  
> >  /**
> >   * stm32f4_adc_start_conv() - Start conversions for regular channels.
> > - * @adc: stm32 adc instance
> > + * @indio_dev: IIO device instance
> >   * @dma: use dma to transfer conversion result
> >   *
> >   * Start conversions for regular channels.
> > @@ -587,8 +589,10 @@ static int stm32_adc_hw_start(struct device *dev)
> >   * conversions, in IIO buffer modes. Otherwise, use ADC interrupt with direct
> >   * DR read instead (e.g. read_raw, or triggered buffer mode without DMA).
> >   */
> > -static void stm32f4_adc_start_conv(struct stm32_adc *adc, bool dma)
> > +static void stm32f4_adc_start_conv(struct iio_dev *indio_dev, bool dma)
> >  {
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> > +
> >  	stm32_adc_set_bits(adc, STM32F4_ADC_CR1, STM32F4_SCAN);
> >  
> >  	if (dma)
> > @@ -605,8 +609,10 @@ static void stm32f4_adc_start_conv(struct stm32_adc *adc, bool dma)
> >  		stm32_adc_set_bits(adc, STM32F4_ADC_CR2, STM32F4_SWSTART);
> >  }
> >  
> > -static void stm32f4_adc_stop_conv(struct stm32_adc *adc)
> > +static void stm32f4_adc_stop_conv(struct iio_dev *indio_dev)
> >  {
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> > +
> >  	stm32_adc_clr_bits(adc, STM32F4_ADC_CR2, STM32F4_EXTEN_MASK);
> >  	stm32_adc_clr_bits(adc, STM32F4_ADC_SR, STM32F4_STRT);
> >  
> > @@ -615,8 +621,9 @@ static void stm32f4_adc_stop_conv(struct stm32_adc *adc)
> >  			   STM32F4_ADON | STM32F4_DMA | STM32F4_DDS);
> >  }
> >  
> > -static void stm32h7_adc_start_conv(struct stm32_adc *adc, bool dma)
> > +static void stm32h7_adc_start_conv(struct iio_dev *indio_dev, bool dma)
> >  {
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	enum stm32h7_adc_dmngt dmngt;
> >  	unsigned long flags;
> >  	u32 val;
> > @@ -635,9 +642,9 @@ static void stm32h7_adc_start_conv(struct stm32_adc *adc, bool dma)
> >  	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTART);
> >  }
> >  
> > -static void stm32h7_adc_stop_conv(struct stm32_adc *adc)
> > +static void stm32h7_adc_stop_conv(struct iio_dev *indio_dev)
> >  {
> > -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	int ret;
> >  	u32 val;
> >  
> > @@ -652,9 +659,9 @@ static void stm32h7_adc_stop_conv(struct stm32_adc *adc)
> >  	stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR, STM32H7_DMNGT_MASK);
> >  }
> >  
> > -static int stm32h7_adc_exit_pwr_down(struct stm32_adc *adc)
> > +static int stm32h7_adc_exit_pwr_down(struct iio_dev *indio_dev)
> >  {
> > -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	int ret;
> >  	u32 val;
> >  
> > @@ -690,9 +697,9 @@ static void stm32h7_adc_enter_pwr_down(struct stm32_adc *adc)
> >  	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
> >  }
> >  
> > -static int stm32h7_adc_enable(struct stm32_adc *adc)
> > +static int stm32h7_adc_enable(struct iio_dev *indio_dev)
> >  {
> > -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	int ret;
> >  	u32 val;
> >  
> > @@ -713,9 +720,9 @@ static int stm32h7_adc_enable(struct stm32_adc *adc)
> >  	return ret;
> >  }
> >  
> > -static void stm32h7_adc_disable(struct stm32_adc *adc)
> > +static void stm32h7_adc_disable(struct iio_dev *indio_dev)
> >  {
> > -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	int ret;
> >  	u32 val;
> >  
> > @@ -730,12 +737,12 @@ static void stm32h7_adc_disable(struct stm32_adc *adc)
> >  
> >  /**
> >   * stm32h7_adc_read_selfcalib() - read calibration shadow regs, save result
> > - * @adc: stm32 adc instance
> > + * @indio_dev: IIO device instance
> >   * Note: Must be called once ADC is enabled, so LINCALRDYW[1..6] are writable
> >   */
> > -static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
> > +static int stm32h7_adc_read_selfcalib(struct iio_dev *indio_dev)
> >  {
> > -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	int i, ret;
> >  	u32 lincalrdyw_mask, val;
> >  
> > @@ -774,12 +781,12 @@ static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
> >  
> >  /**
> >   * stm32h7_adc_restore_selfcalib() - Restore saved self-calibration result
> > - * @adc: stm32 adc instance
> > + * @indio_dev: IIO device instance
> >   * Note: ADC must be enabled, with no on-going conversions.
> >   */
> > -static int stm32h7_adc_restore_selfcalib(struct stm32_adc *adc)
> > +static int stm32h7_adc_restore_selfcalib(struct iio_dev *indio_dev)
> >  {
> > -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	int i, ret;
> >  	u32 lincalrdyw_mask, val;
> >  
> > @@ -847,12 +854,12 @@ static int stm32h7_adc_restore_selfcalib(struct stm32_adc *adc)
> >  
> >  /**
> >   * stm32h7_adc_selfcalib() - Procedure to calibrate ADC
> > - * @adc: stm32 adc instance
> > + * @indio_dev: IIO device instance
> >   * Note: Must be called once ADC is out of power down.
> >   */
> > -static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
> > +static int stm32h7_adc_selfcalib(struct iio_dev *indio_dev)
> >  {
> > -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	int ret;
> >  	u32 val;
> >  
> > @@ -903,7 +910,7 @@ static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
> >  
> >  /**
> >   * stm32h7_adc_prepare() - Leave power down mode to enable ADC.
> > - * @adc: stm32 adc instance
> > + * @indio_dev: IIO device instance
> >   * Leave power down mode.
> >   * Configure channels as single ended or differential before enabling ADC.
> >   * Enable ADC.
> > @@ -912,30 +919,31 @@ static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
> >   * - Only one input is selected for single ended (e.g. 'vinp')
> >   * - Two inputs are selected for differential channels (e.g. 'vinp' & 'vinn')
> >   */
> > -static int stm32h7_adc_prepare(struct stm32_adc *adc)
> > +static int stm32h7_adc_prepare(struct iio_dev *indio_dev)
> >  {
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	int calib, ret;
> >  
> > -	ret = stm32h7_adc_exit_pwr_down(adc);
> > +	ret = stm32h7_adc_exit_pwr_down(indio_dev);
> >  	if (ret)
> >  		return ret;
> >  
> > -	ret = stm32h7_adc_selfcalib(adc);
> > +	ret = stm32h7_adc_selfcalib(indio_dev);
> >  	if (ret < 0)
> >  		goto pwr_dwn;
> >  	calib = ret;
> >  
> >  	stm32_adc_writel(adc, STM32H7_ADC_DIFSEL, adc->difsel);
> >  
> > -	ret = stm32h7_adc_enable(adc);
> > +	ret = stm32h7_adc_enable(indio_dev);
> >  	if (ret)
> >  		goto pwr_dwn;
> >  
> >  	/* Either restore or read calibration result for future reference */
> >  	if (calib)
> > -		ret = stm32h7_adc_restore_selfcalib(adc);
> > +		ret = stm32h7_adc_restore_selfcalib(indio_dev);
> >  	else
> > -		ret = stm32h7_adc_read_selfcalib(adc);
> > +		ret = stm32h7_adc_read_selfcalib(indio_dev);
> >  	if (ret)
> >  		goto disable;
> >  
> > @@ -944,16 +952,18 @@ static int stm32h7_adc_prepare(struct stm32_adc *adc)
> >  	return 0;
> >  
> >  disable:
> > -	stm32h7_adc_disable(adc);
> > +	stm32h7_adc_disable(indio_dev);
> >  pwr_dwn:
> >  	stm32h7_adc_enter_pwr_down(adc);
> >  
> >  	return ret;
> >  }
> >  
> > -static void stm32h7_adc_unprepare(struct stm32_adc *adc)
> > +static void stm32h7_adc_unprepare(struct iio_dev *indio_dev)
> >  {
> > -	stm32h7_adc_disable(adc);
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> > +
> > +	stm32h7_adc_disable(indio_dev);
> >  	stm32h7_adc_enter_pwr_down(adc);
> >  }
> >  
> > @@ -1160,7 +1170,7 @@ static int stm32_adc_single_conv(struct iio_dev *indio_dev,
> >  
> >  	stm32_adc_conv_irq_enable(adc);
> >  
> > -	adc->cfg->start_conv(adc, false);
> > +	adc->cfg->start_conv(indio_dev, false);
> >  
> >  	timeout = wait_for_completion_interruptible_timeout(
> >  					&adc->completion, STM32_ADC_TIMEOUT);
> > @@ -1173,7 +1183,7 @@ static int stm32_adc_single_conv(struct iio_dev *indio_dev,
> >  		ret = IIO_VAL_INT;
> >  	}
> >  
> > -	adc->cfg->stop_conv(adc);
> > +	adc->cfg->stop_conv(indio_dev);
> >  
> >  	stm32_adc_conv_irq_disable(adc);
> >  
> > @@ -1227,8 +1237,8 @@ static int stm32_adc_read_raw(struct iio_dev *indio_dev,
> >  
> >  static irqreturn_t stm32_adc_threaded_isr(int irq, void *data)
> >  {
> > -	struct stm32_adc *adc = data;
> > -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> > +	struct iio_dev *indio_dev = data;
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	const struct stm32_adc_regspec *regs = adc->cfg->regs;
> >  	u32 status = stm32_adc_readl(adc, regs->isr_eoc.reg);
> >  
> > @@ -1240,8 +1250,8 @@ static irqreturn_t stm32_adc_threaded_isr(int irq, void *data)
> >  
> >  static irqreturn_t stm32_adc_isr(int irq, void *data)
> >  {
> > -	struct stm32_adc *adc = data;
> > -	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
> > +	struct iio_dev *indio_dev = data;
> > +	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	const struct stm32_adc_regspec *regs = adc->cfg->regs;
> >  	u32 status = stm32_adc_readl(adc, regs->isr_eoc.reg);
> >  
> > @@ -1514,7 +1524,7 @@ static int __stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
> >  	if (!adc->dma_chan)
> >  		stm32_adc_conv_irq_enable(adc);
> >  
> > -	adc->cfg->start_conv(adc, !!adc->dma_chan);
> > +	adc->cfg->start_conv(indio_dev, !!adc->dma_chan);
> >  
> >  	return 0;
> >  
> > @@ -1547,7 +1557,7 @@ static void __stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
> >  	struct stm32_adc *adc = iio_priv(indio_dev);
> >  	struct device *dev = indio_dev->dev.parent;
> >  
> > -	adc->cfg->stop_conv(adc);
> > +	adc->cfg->stop_conv(indio_dev);
> >  	if (!adc->dma_chan)
> >  		stm32_adc_conv_irq_disable(adc);
> >  
> > @@ -1891,7 +1901,7 @@ static int stm32_adc_probe(struct platform_device *pdev)
> >  	indio_dev->info = &stm32_adc_iio_info;
> >  	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_HARDWARE_TRIGGERED;
> >  
> > -	platform_set_drvdata(pdev, adc);
> > +	platform_set_drvdata(pdev, indio_dev);
> >  
> >  	ret = of_property_read_u32(pdev->dev.of_node, "reg", &adc->offset);
> >  	if (ret != 0) {
> > @@ -1905,7 +1915,7 @@ static int stm32_adc_probe(struct platform_device *pdev)
> >  
> >  	ret = devm_request_threaded_irq(&pdev->dev, adc->irq, stm32_adc_isr,
> >  					stm32_adc_threaded_isr,
> > -					0, pdev->name, adc);
> > +					0, pdev->name, indio_dev);
> >  	if (ret) {
> >  		dev_err(&pdev->dev, "failed to request IRQ\n");
> >  		return ret;
> > @@ -1989,8 +1999,8 @@ static int stm32_adc_probe(struct platform_device *pdev)
> >  
> >  static int stm32_adc_remove(struct platform_device *pdev)
> >  {
> > -	struct stm32_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_adc *adc = iio_priv(indio_dev);
> >  
> >  	pm_runtime_get_sync(&pdev->dev);
> >  	iio_device_unregister(indio_dev);
> > @@ -2012,8 +2022,7 @@ static int stm32_adc_remove(struct platform_device *pdev)
> >  #if defined(CONFIG_PM_SLEEP)
> >  static int stm32_adc_suspend(struct device *dev)
> >  {
> > -	struct stm32_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_adc_buffer_predisable(indio_dev);
> > @@ -2023,8 +2032,7 @@ static int stm32_adc_suspend(struct device *dev)
> >  
> >  static int stm32_adc_resume(struct device *dev)
> >  {
> > -	struct stm32_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);
> >  	int ret;
> >  
> >  	ret = pm_runtime_force_resume(dev);
> >   

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