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iio: adc: stm32: add trigger polarity extended attribute

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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>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Fabrice Gasnier 2017-01-26 15:28:31 +01:00 committed by Jonathan Cameron
parent f24a33b3e2
commit 732f2dc468
2 changed files with 63 additions and 1 deletions
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18
Documentation/ABI/testing/sysfs-bus-iio-adc-stm32 Normal file
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@ -0,0 +1,18 @@
What: /sys/bus/iio/devices/triggerX/trigger_polarity
KernelVersion: 4.11
Contact: fabrice.gasnier@st.com
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@st.com
Description:
List all available trigger_polarity settings.

46
drivers/iio/adc/stm32-adc.c
View File

@ -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)