Re: [PATCH] iio: stm32-adc: keep a reference to the iio device on the state struct
From: Jonathan Cameron <jic23@kernel.org>
Date: 2020-05-24 13:09:25
Also in:
linux-iio, lkml
On Fri, 22 May 2020 16:07:19 +0300 Alexandru Ardelean [off-list ref] 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. For this driver, not using iio_priv_to_dev(), means keeping a reference to the IIO device on the state struct. Signed-off-by: Alexandru Ardelean <redacted>
I don't particularly mind this approach, but an alternative would be to change the callbacks to take an iio_dev rather than the iio_priv() structure. It's more invasive though as need to change what is provided via dev_get_drvdata for the adc device. It's possible I missed a path where this won't work for some reason though. Up to the driver maintainers on which one they prefer. Thanks, Jonathan
quoted hunk ↗ jump to hunk
--- drivers/iio/adc/stm32-adc.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-)diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index ae622ee6d08c..7e58c4443e3f 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c@@ -171,6 +171,7 @@ struct stm32_adc_cfg { /** * struct stm32_adc - private data of each ADC IIO instance + * @indio_dev: back-reference to the IIO device object * @common: reference to ADC block common data * @offset: ADC instance register offset in ADC block * @cfg: compatible configuration data@@ -194,6 +195,7 @@ struct stm32_adc_cfg { * @chan_name: channel name array */ struct stm32_adc { + struct iio_dev *indio_dev; struct stm32_adc_common *common; u32 offset; const struct stm32_adc_cfg *cfg;@@ -637,7 +639,7 @@ static void stm32h7_adc_start_conv(struct stm32_adc *adc, bool dma) static void stm32h7_adc_stop_conv(struct stm32_adc *adc) { - struct iio_dev *indio_dev = iio_priv_to_dev(adc); + struct iio_dev *indio_dev = adc->indio_dev; int ret; u32 val;@@ -654,7 +656,7 @@ static void stm32h7_adc_stop_conv(struct stm32_adc *adc) static int stm32h7_adc_exit_pwr_down(struct stm32_adc *adc) { - struct iio_dev *indio_dev = iio_priv_to_dev(adc); + struct iio_dev *indio_dev = adc->indio_dev; int ret; u32 val;@@ -692,7 +694,7 @@ static void stm32h7_adc_enter_pwr_down(struct stm32_adc *adc) static int stm32h7_adc_enable(struct stm32_adc *adc) { - struct iio_dev *indio_dev = iio_priv_to_dev(adc); + struct iio_dev *indio_dev = adc->indio_dev; int ret; u32 val;@@ -715,7 +717,7 @@ static int stm32h7_adc_enable(struct stm32_adc *adc) static void stm32h7_adc_disable(struct stm32_adc *adc) { - struct iio_dev *indio_dev = iio_priv_to_dev(adc); + struct iio_dev *indio_dev = adc->indio_dev; int ret; u32 val;@@ -735,7 +737,7 @@ static void stm32h7_adc_disable(struct stm32_adc *adc) */ static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc) { - struct iio_dev *indio_dev = iio_priv_to_dev(adc); + struct iio_dev *indio_dev = adc->indio_dev; int i, ret; u32 lincalrdyw_mask, val;@@ -779,7 +781,7 @@ static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc) */ static int stm32h7_adc_restore_selfcalib(struct stm32_adc *adc) { - struct iio_dev *indio_dev = iio_priv_to_dev(adc); + struct iio_dev *indio_dev = adc->indio_dev; int i, ret; u32 lincalrdyw_mask, val;@@ -852,7 +854,7 @@ static int stm32h7_adc_restore_selfcalib(struct stm32_adc *adc) */ static int stm32h7_adc_selfcalib(struct stm32_adc *adc) { - struct iio_dev *indio_dev = iio_priv_to_dev(adc); + struct iio_dev *indio_dev = adc->indio_dev; int ret; u32 val;@@ -1228,7 +1230,7 @@ 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 = adc->indio_dev; const struct stm32_adc_regspec *regs = adc->cfg->regs; u32 status = stm32_adc_readl(adc, regs->isr_eoc.reg);@@ -1241,7 +1243,7 @@ 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 = adc->indio_dev; const struct stm32_adc_regspec *regs = adc->cfg->regs; u32 status = stm32_adc_readl(adc, regs->isr_eoc.reg);@@ -1879,6 +1881,7 @@ static int stm32_adc_probe(struct platform_device *pdev) return -ENOMEM; adc = iio_priv(indio_dev); + adc->indio_dev = indio_dev; adc->common = dev_get_drvdata(pdev->dev.parent); spin_lock_init(&adc->lock); init_completion(&adc->completion);@@ -1990,7 +1993,7 @@ 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 = adc->indio_dev; pm_runtime_get_sync(&pdev->dev); iio_device_unregister(indio_dev);@@ -2013,7 +2016,7 @@ static int stm32_adc_remove(struct platform_device *pdev) 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 = adc->indio_dev; if (iio_buffer_enabled(indio_dev)) __stm32_adc_buffer_predisable(indio_dev);@@ -2024,7 +2027,7 @@ 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 = adc->indio_dev; int ret; ret = pm_runtime_force_resume(dev);
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