[PATCH v3 6/6] iio: adc: stm32: add support for EXTI trigger
From: jic23@kernel.org (Jonathan Cameron)
Date: 2017-03-05 12:21:55
Also in:
linux-devicetree, linux-iio, lkml
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 <redacted>
Minor question inline. J
quoted hunk ↗ jump to hunk
--- 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,