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SubjectRe: [PATCH v3 6/6] iio: adc: stm32: add support for EXTI trigger
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On 28/02/17 16:51, Fabrice Gasnier wrote:
> EXTi (external interrupt) signal can be routed internally as trigger
> source for ADC conversions: STM32F4 ADC can use EXTI11.
>
> Retrieve interrupt trigger from DT, so it can be muxed into ADC IP,
> via extsel.
>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Minor question inline.
J
> ---
> drivers/iio/adc/stm32-adc.c | 27 ++++++++++++++++++++++++---
> 1 file changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index 9b49a6ad..4d9040d 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -108,6 +108,9 @@ enum stm32_adc_extsel {
> STM32_EXT15,
> };
>
> +/* EXTI 11 trigger selection on STM32F4 */
> +#define STM32F4_EXTI11_EXTSEL STM32_EXT15
> +
> /**
> * struct stm32_adc_trig_info - ADC trigger info
> * @name: name of the trigger, corresponding to its source
> @@ -146,6 +149,7 @@ struct stm32_adc_regs {
> * @rx_buf: dma rx buffer cpu address
> * @rx_dma_buf: dma rx buffer bus address
> * @rx_buf_sz: dma rx buffer size
> + * @exti_trig EXTI trigger
> */
> struct stm32_adc {
> struct stm32_adc_common *common;
> @@ -162,6 +166,7 @@ struct stm32_adc {
> u8 *rx_buf;
> dma_addr_t rx_dma_buf;
> unsigned int rx_buf_sz;
> + struct iio_trigger *exti_trig;
> };
>
> /**
> @@ -395,10 +400,15 @@ static int stm32_adc_conf_scan_seq(struct iio_dev *indio_dev,
> *
> * Returns trigger extsel value, if trig matches, -EINVAL otherwise.
> */
> -static int stm32_adc_get_trig_extsel(struct iio_trigger *trig)
> +static int stm32_adc_get_trig_extsel(struct iio_dev *indio_dev,
> + struct iio_trigger *trig)
> {
> + struct stm32_adc *adc = iio_priv(indio_dev);
> int i;
>
> + if (trig == adc->exti_trig)
> + return STM32F4_EXTI11_EXTSEL;
> +
> /* lookup triggers registered by stm32 timer trigger driver */
> for (i = 0; stm32f4_adc_trigs[i].name; i++) {
> /**
> @@ -432,7 +442,7 @@ static int stm32_adc_set_trig(struct iio_dev *indio_dev,
> int ret;
>
> if (trig) {
> - ret = stm32_adc_get_trig_extsel(trig);
> + ret = stm32_adc_get_trig_extsel(indio_dev, trig);
> if (ret < 0)
> return ret;
>
> @@ -604,7 +614,7 @@ static irqreturn_t stm32_adc_isr(int irq, void *data)
> static int stm32_adc_validate_trigger(struct iio_dev *indio_dev,
> struct iio_trigger *trig)
> {
> - return stm32_adc_get_trig_extsel(trig) < 0 ? -EINVAL : 0;
> + return stm32_adc_get_trig_extsel(indio_dev, trig) < 0 ? -EINVAL : 0;
> }
>
> static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
> @@ -1030,6 +1040,17 @@ static int stm32_adc_probe(struct platform_device *pdev)
> if (ret < 0)
> goto err_clk_disable;
>
> + adc->exti_trig = devm_iio_trigger_get_by_name(&pdev->dev, "exti");
Can we tighten this in any way? If not I guess we'll have to rely on no
one messing up the devicetree to put the wrong trigger in there with this name.

> + if (IS_ERR(adc->exti_trig)) {
> + ret = PTR_ERR(adc->exti_trig);
> + if (ret == -EPROBE_DEFER)
> + goto err_dma_disable;
> + dev_dbg(&pdev->dev, "No exti trigger found (%d)\n", ret);
> + adc->exti_trig = NULL;
> + } else {
> + dev_info(&pdev->dev, "Can use %s\n", adc->exti_trig->name);
> + }
> +
> ret = iio_triggered_buffer_setup(indio_dev,
> &iio_pollfunc_store_time,
> &stm32_adc_trigger_handler,
>

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