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Subject[PATCH v3 6/6] iio: adc: stm32: add support for EXTI trigger
Date
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>
---
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");
+ 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,
--
1.9.1
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