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@xxxxxx>
---
Changes in v2:
- Rename and document new trigger_polarity custom attribute
---
Documentation/ABI/testing/sysfs-bus-iio-adc-stm32 | 18 +++++++++
drivers/iio/adc/stm32-adc.c | 46 ++++++++++++++++++++++-
2 files changed, 63 insertions(+), 1 deletion(-)
create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-adc-stm32
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-adc-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-adc-stm32
new file mode 100644
index 0000000..efe4c85
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-adc-stm32
@@ -0,0 +1,18 @@
+What: /sys/bus/iio/devices/triggerX/trigger_polarity
+KernelVersion: 4.11
+Contact: fabrice.gasnier@xxxxxx
+Description:
+ The STM32 ADC can be configured to use external trigger sources
+ (e.g. timers, pwm or exti gpio). Then, it can be tuned to start
+ conversions on external trigger by either:
+ - "rising-edge"
+ - "falling-edge"
+ - "both-edges".
+ Reading returns current trigger polarity.
+ Writing value before enabling conversions sets trigger polarity.
+
+What: /sys/bus/iio/devices/triggerX/trigger_polarity_available
+KernelVersion: 4.11
+Contact: fabrice.gasnier@xxxxxx
+Description:
+ List all available trigger_polarity settings.
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 87d984b..9a38f9a 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -135,6 +135,7 @@ struct stm32_adc_regs {
* @lock: spinlock
* @bufi: data buffer index
* @num_conv: expected number of scan conversions
+ * @trigger_polarity: external trigger polarity (e.g. exten)
*/
struct stm32_adc {
struct stm32_adc_common *common;
@@ -146,6 +147,7 @@ struct stm32_adc {
spinlock_t lock; /* interrupt lock */
unsigned int bufi;
unsigned int num_conv;
+ u32 trigger_polarity;
};
/**
@@ -410,7 +412,7 @@ static int stm32_adc_set_trig(struct iio_dev *indio_dev,
/* set trigger source and polarity (default to rising edge) */
extsel = ret;
- exten = STM32_EXTEN_HWTRIG_RISING_EDGE;
+ exten = adc->trigger_polarity + STM32_EXTEN_HWTRIG_RISING_EDGE;
}
spin_lock_irqsave(&adc->lock, flags);
@@ -424,6 +426,36 @@ 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->trigger_polarity = 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->trigger_polarity;
+}
+
+static const char * const stm32_trig_pol_items[] = {
+ "rising-edge", "falling-edge", "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
@@ -682,6 +714,17 @@ 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_polarity", IIO_SHARED_BY_ALL, &stm32_adc_trig_pol),
+ {
+ .name = "trigger_polarity_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,
@@ -697,6 +740,7 @@ 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)
--
1.9.1
--
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