Re: [PATCH 2/7] iio: adc: stm32: Enable use of stm32 timer triggers

[Fabrice Gasnier <fabrice.gasnier@xxxxxx>]

On 01/22/2017 01:55 PM, Jonathan Cameron wrote:
> On 19/01/17 13:34, Fabrice Gasnier wrote:
> > STM32 ADC has external timer trigger sources. Use stm32 timer triggers
> > API (e.g. is_stm32_timer_trigger()) with local ADC lookup table to
> > validate a trigger can be used.
> > This also provides correct trigger selection value (e.g. extsel).
> >
> > Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
> Looks good. Observations inline.
> > ---
> >  drivers/iio/adc/Kconfig     |  2 ++
> >  drivers/iio/adc/stm32-adc.c | 60 +++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 62 insertions(+)
> >
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index 33341f4..9a7b090 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -447,6 +447,8 @@ config STM32_ADC_CORE
> >  	depends on OF
> >  	depends on REGULATOR
> >  	select IIO_BUFFER
> > +	select MFD_STM32_TIMERS
> > +	select IIO_STM32_TIMER_TRIGGER
> >  	select IIO_TRIGGERED_BUFFER
> >  	help
> >  	  Select this option to enable the core driver for STMicroelectronics
> > diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> > index 8d0b74b..30708bc 100644
> > --- a/drivers/iio/adc/stm32-adc.c
> > +++ b/drivers/iio/adc/stm32-adc.c
> > @@ -23,6 +23,7 @@
> >  #include <linux/delay.h>
> >  #include <linux/iio/iio.h>
> >  #include <linux/iio/buffer.h>
> > +#include <linux/iio/timer/stm32-timer-trigger.h>
> >  #include <linux/iio/trigger.h>
> >  #include <linux/iio/trigger_consumer.h>
> >  #include <linux/iio/triggered_buffer.h>
> > @@ -122,6 +123,35 @@ enum stm32_adc_exten {
> >  	STM32_EXTEN_HWTRIG_BOTH_EDGES,
> >  };
> >
> > +/* extsel - trigger mux selection value */
> > +enum stm32_adc_extsel {
> > +	STM32_EXT0,
> > +	STM32_EXT1,
> > +	STM32_EXT2,
> > +	STM32_EXT3,
> > +	STM32_EXT4,
> > +	STM32_EXT5,
> > +	STM32_EXT6,
> > +	STM32_EXT7,
> > +	STM32_EXT8,
> > +	STM32_EXT9,
> > +	STM32_EXT10,
> > +	STM32_EXT11,
> > +	STM32_EXT12,
> > +	STM32_EXT13,
> > +	STM32_EXT14,
> > +	STM32_EXT15,
> > +};
> > +
> > +/**
> > + * struct stm32_adc_trig_info - ADC trigger info
> > + * @name:		name of the trigger, corresponding to its source
> > + * @extsel:		trigger selection
> > + */
> > +struct stm32_adc_trig_info {
> > +	const char *name;
> > +	enum stm32_adc_extsel extsel;
> > +};
> >
> >  /**
> >   * struct stm32_adc - private data of each ADC IIO instance
> > @@ -218,6 +248,26 @@ struct stm32_adc_regs {
> >  	{ STM32F4_ADC_SQR1, STM32F4_SQ16_MASK, STM32F4_SQ16_SHIFT },
> >  };
> >
> > +/* STM32F4 external trigger sources for all instances */
> > +static struct stm32_adc_trig_info stm32f4_adc_timer_trigs[] = {
> > +	{ TIM1_CH1, STM32_EXT0 },
> > +	{ TIM1_CH2, STM32_EXT1 },
> > +	{ TIM1_CH3, STM32_EXT2 },
> > +	{ TIM2_CH2, STM32_EXT3 },
> > +	{ TIM2_CH3, STM32_EXT4 },
> > +	{ TIM2_CH4, STM32_EXT5 },
> > +	{ TIM2_TRGO, STM32_EXT6 },
> > +	{ TIM3_CH1, STM32_EXT7 },
> > +	{ TIM3_TRGO, STM32_EXT8 },
> > +	{ TIM4_CH4, STM32_EXT9 },
> > +	{ TIM5_CH1, STM32_EXT10 },
> > +	{ TIM5_CH2, STM32_EXT11 },
> > +	{ TIM5_CH3, STM32_EXT12 },
> > +	{ TIM8_CH1, STM32_EXT13 },
> > +	{ TIM8_TRGO, STM32_EXT14 },
> > +	{}, /* sentinel */
> > +};
> > +
> >  /**
> >   * STM32 ADC registers access routines
> >   * @adc: stm32 adc instance
> > @@ -362,6 +412,16 @@ static int stm32_adc_conf_scan_seq(struct iio_dev *indio_dev,
> >  static int stm32_adc_get_trig_extsel(struct iio_dev *indio_dev,
> >  				     struct iio_trigger *trig)
> >  {
> > +	int i;
> Ah. This makes more sense than patch 1 on it's own did.
> > +
> > +	/* lookup triggers registered by stm32 timer trigger driver */
> > +	for (i = 0; stm32f4_adc_timer_trigs[i].name; i++) {
> > +		if (is_stm32_timer_trigger(trig) &&
> > +		    !strcmp(stm32f4_adc_timer_trigs[i].name, trig->name)) {
> > +			return stm32f4_adc_timer_trigs[i].extsel;
> Good. The combination of the first check and the name match should make this safe
> against those triggers that can be assigned arbitrary names.

Do you wish I add a comment about it ?

Best Regards,
Fabrice

> > +		}
> > +	}
> > +
> >  	return -EINVAL;
> >  }
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