Re: [PATCH 3/7] iio: adc: stm32: add trigger polarity extended attribute

Jonathan Cameron
2017-01-22T12:58:10Z

On 19/01/17 13:34, Fabrice Gasnier wrote:
> Define extended attribute so that user may choose rising, falling or both
> edges for external trigger sources.
> Default to rising edge in case it isn't set.
>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Creates a custom attibute. Documentation please!
/Documentation/ABI/testing/sysfs-bus-iio-stm32 or similar.

The approach seems reasonable, but easier to discuss when it's
formally described.

I'd also not care about characters saved and go with
trigger_polarity rather than the short form (unless this you have
a good reason for it!)

Jonathan
> ---
> drivers/iio/adc/stm32-adc.c | 51 ++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 50 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index 30708bc..9753c39 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -164,6 +164,7 @@ struct stm32_adc_trig_info {
> * @lock: spinlock
> * @bufi: data buffer index
> * @num_conv: expected number of scan conversions
> + * @exten: external trigger config (enable/polarity)
> */
> struct stm32_adc {
> struct stm32_adc_common *common;
> @@ -175,6 +176,7 @@ struct stm32_adc {
> spinlock_t lock; /* interrupt lock */
> int bufi;
> int num_conv;
> + enum stm32_adc_exten exten;
> };
>
> /**
> @@ -449,7 +451,9 @@ static int stm32_adc_set_trig(struct iio_dev *indio_dev,
>
> /* set trigger source, default to rising edge */
> extsel = ret;
> - exten = STM32_EXTEN_HWTRIG_RISING_EDGE;
> + if (adc->exten == STM32_EXTEN_SWTRIG)
> + adc->exten = STM32_EXTEN_HWTRIG_RISING_EDGE;
> + exten = adc->exten;
> }
>
> spin_lock_irqsave(&adc->lock, flags);
> @@ -463,6 +467,39 @@ static int stm32_adc_set_trig(struct iio_dev *indio_dev,
> return 0;
> }
>
> +static int stm32_adc_set_trig_pol(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + unsigned int type)
> +{
> + struct stm32_adc *adc = iio_priv(indio_dev);
> +
> + adc->exten = type;
> +
> + return 0;
> +}
> +
> +static int stm32_adc_get_trig_pol(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan)
> +{
> + struct stm32_adc *adc = iio_priv(indio_dev);
> +
> + return adc->exten;
> +}
> +
> +static const char * const stm32_trig_pol_items[] = {
> + [STM32_EXTEN_SWTRIG] = "swtrig",
> + [STM32_EXTEN_HWTRIG_RISING_EDGE] = "rising-edge",
> + [STM32_EXTEN_HWTRIG_FALLING_EDGE] = "falling-edge",
> + [STM32_EXTEN_HWTRIG_BOTH_EDGES] = "both-edges",
> +};
> +
> +const struct iio_enum stm32_adc_trig_pol = {
> + .items = stm32_trig_pol_items,
> + .num_items = ARRAY_SIZE(stm32_trig_pol_items),
> + .get = stm32_adc_get_trig_pol,
> + .set = stm32_adc_set_trig_pol,
> +};
> +
> /**
> * stm32_adc_single_conv() - Performs a single conversion
> * @indio_dev: IIO device
> @@ -745,6 +782,17 @@ static irqreturn_t stm32_adc_trigger_handler(int irq, void *p)
> return IRQ_HANDLED;
> }
>
> +static const struct iio_chan_spec_ext_info stm32_adc_ext_info[] = {
> + IIO_ENUM("trigger_pol", IIO_SHARED_BY_ALL, &stm32_adc_trig_pol),
> + {
> + .name = "trigger_pol_available",
> + .shared = IIO_SHARED_BY_ALL,
> + .read = iio_enum_available_read,
> + .private = (uintptr_t)&stm32_adc_trig_pol,
> + },
> + {},
> +};
> +
> static void stm32_adc_chan_init_one(struct iio_dev *indio_dev,
> struct iio_chan_spec *chan,
> const struct stm32_adc_chan_spec *channel,
> @@ -760,6 +808,7 @@ static void stm32_adc_chan_init_one(struct iio_dev *indio_dev,
> chan->scan_type.sign = 'u';
> chan->scan_type.realbits = 12;
> chan->scan_type.storagebits = 16;
> + chan->ext_info = stm32_adc_ext_info;
> }
>
> static int stm32_adc_chan_of_init(struct iio_dev *indio_dev)
>