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[PATCH 3/7] iio: adc: stm32: add trigger polarity extended attribute

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  [PATCH 3/7] iio: adc: stm32: add trigger polarity extended attribute Fabrice Gasnier <fabrice.gasnier@st.com> - 2017-01-19 14:40 +0100
    Re: [PATCH 3/7] iio: adc: stm32: add trigger polarity extended  attribute Jonathan Cameron <jic23@kernel.org> - 2017-01-22 14:00 +0100
      Re: [PATCH 3/7] iio: adc: stm32: add trigger polarity extended  attribute Fabrice Gasnier <fabrice.gasnier@st.com> - 2017-01-24 15:50 +0100

#1562735 — [PATCH 3/7] iio: adc: stm32: add trigger polarity extended attribute

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>
---
 drivers/iio/adc/stm32-adc.c | 51 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 30708bc..9753c39 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -164,6 +164,7 @@ struct stm32_adc_trig_info {
  * @lock:		spinlock
  * @bufi:		data buffer index
  * @num_conv:		expected number of scan conversions
+ * @exten:		external trigger config (enable/polarity)
  */
 struct stm32_adc {
 	struct stm32_adc_common	*common;
@@ -175,6 +176,7 @@ struct stm32_adc {
 	spinlock_t		lock;		/* interrupt lock */
 	int			bufi;
 	int			num_conv;
+	enum stm32_adc_exten	exten;
 };
 
 /**
@@ -449,7 +451,9 @@ static int stm32_adc_set_trig(struct iio_dev *indio_dev,
 
 		/* set trigger source, default to rising edge */
 		extsel = ret;
-		exten = STM32_EXTEN_HWTRIG_RISING_EDGE;
+		if (adc->exten == STM32_EXTEN_SWTRIG)
+			adc->exten = STM32_EXTEN_HWTRIG_RISING_EDGE;
+		exten = adc->exten;
 	}
 
 	spin_lock_irqsave(&adc->lock, flags);
@@ -463,6 +467,39 @@ 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->exten = 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->exten;
+}
+
+static const char * const stm32_trig_pol_items[] = {
+	[STM32_EXTEN_SWTRIG] = "swtrig",
+	[STM32_EXTEN_HWTRIG_RISING_EDGE] = "rising-edge",
+	[STM32_EXTEN_HWTRIG_FALLING_EDGE] = "falling-edge",
+	[STM32_EXTEN_HWTRIG_BOTH_EDGES] = "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
@@ -745,6 +782,17 @@ 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_pol", IIO_SHARED_BY_ALL, &stm32_adc_trig_pol),
+	{
+		.name = "trigger_pol_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,
@@ -760,6 +808,7 @@ 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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#1564394 — Re: [PATCH 3/7] iio: adc: stm32: add trigger polarity extended attribute

On 19/01/17 13:34, Fabrice Gasnier wrote:
> 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>
Creates a custom attibute.  Documentation please!
/Documentation/ABI/testing/sysfs-bus-iio-stm32 or similar.

The approach seems reasonable, but easier to discuss when it's
formally described.

I'd also not care about characters saved and go with 
trigger_polarity rather than the short form (unless this you have
a good reason for it!)

Jonathan
> ---
>  drivers/iio/adc/stm32-adc.c | 51 ++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 50 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index 30708bc..9753c39 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -164,6 +164,7 @@ struct stm32_adc_trig_info {
>   * @lock:		spinlock
>   * @bufi:		data buffer index
>   * @num_conv:		expected number of scan conversions
> + * @exten:		external trigger config (enable/polarity)
>   */
>  struct stm32_adc {
>  	struct stm32_adc_common	*common;
> @@ -175,6 +176,7 @@ struct stm32_adc {
>  	spinlock_t		lock;		/* interrupt lock */
>  	int			bufi;
>  	int			num_conv;
> +	enum stm32_adc_exten	exten;
>  };
>  
>  /**
> @@ -449,7 +451,9 @@ static int stm32_adc_set_trig(struct iio_dev *indio_dev,
>  
>  		/* set trigger source, default to rising edge */
>  		extsel = ret;
> -		exten = STM32_EXTEN_HWTRIG_RISING_EDGE;
> +		if (adc->exten == STM32_EXTEN_SWTRIG)
> +			adc->exten = STM32_EXTEN_HWTRIG_RISING_EDGE;
> +		exten = adc->exten;
>  	}
>  
>  	spin_lock_irqsave(&adc->lock, flags);
> @@ -463,6 +467,39 @@ 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->exten = 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->exten;
> +}
> +
> +static const char * const stm32_trig_pol_items[] = {
> +	[STM32_EXTEN_SWTRIG] = "swtrig",
> +	[STM32_EXTEN_HWTRIG_RISING_EDGE] = "rising-edge",
> +	[STM32_EXTEN_HWTRIG_FALLING_EDGE] = "falling-edge",
> +	[STM32_EXTEN_HWTRIG_BOTH_EDGES] = "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
> @@ -745,6 +782,17 @@ 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_pol", IIO_SHARED_BY_ALL, &stm32_adc_trig_pol),
> +	{
> +		.name = "trigger_pol_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,
> @@ -760,6 +808,7 @@ 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)
> 

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#1565908 — Re: [PATCH 3/7] iio: adc: stm32: add trigger polarity extended attribute

On 01/22/2017 01:58 PM, Jonathan Cameron wrote:
> On 19/01/17 13:34, Fabrice Gasnier wrote:
>> 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>
> Creates a custom attibute.  Documentation please!
> /Documentation/ABI/testing/sysfs-bus-iio-stm32 or similar.

Ok, I'll add something like:
Documentation/ABI/testing/sysfs-bus-iio-adc-stm32:

+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.

Best Regards,
Thanks,
Fabrice
>
> The approach seems reasonable, but easier to discuss when it's
> formally described.
>
> I'd also not care about characters saved and go with
> trigger_polarity rather than the short form (unless this you have
> a good reason for it!)
>
> Jonathan
>> ---
>>  drivers/iio/adc/stm32-adc.c | 51 ++++++++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 50 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
>> index 30708bc..9753c39 100644
>> --- a/drivers/iio/adc/stm32-adc.c
>> +++ b/drivers/iio/adc/stm32-adc.c
>> @@ -164,6 +164,7 @@ struct stm32_adc_trig_info {
>>   * @lock:		spinlock
>>   * @bufi:		data buffer index
>>   * @num_conv:		expected number of scan conversions
>> + * @exten:		external trigger config (enable/polarity)
>>   */
>>  struct stm32_adc {
>>  	struct stm32_adc_common	*common;
>> @@ -175,6 +176,7 @@ struct stm32_adc {
>>  	spinlock_t		lock;		/* interrupt lock */
>>  	int			bufi;
>>  	int			num_conv;
>> +	enum stm32_adc_exten	exten;
>>  };
>>
>>  /**
>> @@ -449,7 +451,9 @@ static int stm32_adc_set_trig(struct iio_dev *indio_dev,
>>
>>  		/* set trigger source, default to rising edge */
>>  		extsel = ret;
>> -		exten = STM32_EXTEN_HWTRIG_RISING_EDGE;
>> +		if (adc->exten == STM32_EXTEN_SWTRIG)
>> +			adc->exten = STM32_EXTEN_HWTRIG_RISING_EDGE;
>> +		exten = adc->exten;
>>  	}
>>
>>  	spin_lock_irqsave(&adc->lock, flags);
>> @@ -463,6 +467,39 @@ 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->exten = 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->exten;
>> +}
>> +
>> +static const char * const stm32_trig_pol_items[] = {
>> +	[STM32_EXTEN_SWTRIG] = "swtrig",
>> +	[STM32_EXTEN_HWTRIG_RISING_EDGE] = "rising-edge",
>> +	[STM32_EXTEN_HWTRIG_FALLING_EDGE] = "falling-edge",
>> +	[STM32_EXTEN_HWTRIG_BOTH_EDGES] = "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
>> @@ -745,6 +782,17 @@ 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_pol", IIO_SHARED_BY_ALL, &stm32_adc_trig_pol),
>> +	{
>> +		.name = "trigger_pol_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,
>> @@ -760,6 +808,7 @@ 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)
>>
>

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