[v2,1/2] Input: rotary-encoder: Add 'stepped' irq handler
diff mbox series

Message ID 1380891203-17617-2-git-send-email-ezequiel@vanguardiasur.com.ar
State New, archived
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Series
  • rotary-encoder: Add new interruption handler
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Commit Message

Ezequiel Garcia Oct. 4, 2013, 12:53 p.m. UTC
Some rotary-encoder devices (such as those with detents) are capable
of producing a stable event on each step. This commit adds support
for this case, by implementing a new interruption handler.

The handler needs only detect the direction of the turn and generate
an event according to this detection.

Cc: Daniel Mack <zonque@gmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
---
v1->v2:
  * Add DT property handling
  * Replace binary representation by hexa-decimal in the sum encoding

 drivers/input/misc/rotary_encoder.c | 41 +++++++++++++++++++++++++++++++++++++
 include/linux/rotary_encoder.h      |  1 +
 2 files changed, 42 insertions(+)

Comments

Daniel Mack Oct. 4, 2013, 1:18 p.m. UTC | #1
On 04.10.2013 14:53, Ezequiel Garcia wrote:
> Some rotary-encoder devices (such as those with detents) are capable
> of producing a stable event on each step. This commit adds support
> for this case, by implementing a new interruption handler.
> 
> The handler needs only detect the direction of the turn and generate
> an event according to this detection.

I think you can squash patch 2/2 into this one. It doesn't make much
sense to have a one-liner patch to just update the documenation separately.

Other than that, the code looks fine to me.

  Acked-by: Daniel Mack <zonque@gmail.com>


Thanks,
Daniel


> 
> Cc: Daniel Mack <zonque@gmail.com>
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
> ---
> v1->v2:
>   * Add DT property handling
>   * Replace binary representation by hexa-decimal in the sum encoding
> 
>  drivers/input/misc/rotary_encoder.c | 41 +++++++++++++++++++++++++++++++++++++
>  include/linux/rotary_encoder.h      |  1 +
>  2 files changed, 42 insertions(+)
> 
> diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
> index 5b1aff8..6c7a554 100644
> --- a/drivers/input/misc/rotary_encoder.c
> +++ b/drivers/input/misc/rotary_encoder.c
> @@ -117,6 +117,42 @@ static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> +static irqreturn_t rotary_encoder_stepped_irq(int irq, void *dev_id)
> +{
> +	struct rotary_encoder *encoder = dev_id;
> +	int state;
> +	unsigned char sum;
> +
> +	state = rotary_encoder_get_state(encoder->pdata);
> +
> +	/*
> +	 * We encode the previous and the current state using a byte.
> +	 * The previous state in the MSB nibble, the current state in the LSB
> +	 * nibble. Then use a table to decide the direction of the turn.
> +	 */
> +	sum = (encoder->last_stable << 4) + state;
> +	switch (sum) {
> +	case 0x31:
> +	case 0x10:
> +	case 0x02:
> +	case 0x23:
> +		encoder->dir = 0; /* clockwise */
> +		break;
> +	/*
> +	 * TODO: Add the other case, and the illegal values should
> +	 * say a WARN (it's a BUG, but we won't stop the kernel for it :)
> +	 */
> +	default:
> +		encoder->dir = 1;
> +	}
> +
> +	rotary_encoder_report_event(encoder);
> +
> +	encoder->last_stable = state;
> +
> +	return IRQ_HANDLED;
> +}
> +
>  static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
>  {
>  	struct rotary_encoder *encoder = dev_id;
> @@ -180,6 +216,8 @@ static struct rotary_encoder_platform_data *rotary_encoder_parse_dt(struct devic
>  					"rotary-encoder,rollover", NULL);
>  	pdata->half_period = !!of_get_property(np,
>  					"rotary-encoder,half-period", NULL);
> +	pdata->on_each_step = !!of_get_property(np,
> +					"rotary-encoder,on-each-step", NULL);
>  
>  	return pdata;
>  }
> @@ -254,6 +292,9 @@ static int rotary_encoder_probe(struct platform_device *pdev)
>  	if (pdata->half_period) {
>  		handler = &rotary_encoder_half_period_irq;
>  		encoder->last_stable = rotary_encoder_get_state(pdata);
> +	} else if (pdata->on_each_step) {
> +		handler = &rotary_encoder_stepped_irq;
> +		encoder->last_stable = rotary_encoder_get_state(pdata);
>  	} else {
>  		handler = &rotary_encoder_irq;
>  	}
> diff --git a/include/linux/rotary_encoder.h b/include/linux/rotary_encoder.h
> index 3f594dc..499f6f7 100644
> --- a/include/linux/rotary_encoder.h
> +++ b/include/linux/rotary_encoder.h
> @@ -11,6 +11,7 @@ struct rotary_encoder_platform_data {
>  	bool relative_axis;
>  	bool rollover;
>  	bool half_period;
> +	bool on_each_step;
>  };
>  
>  #endif /* __ROTARY_ENCODER_H__ */
> 

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Ezequiel Garcia Oct. 12, 2013, 4:58 p.m. UTC | #2
Dmitry,

On 4 October 2013 10:18, Daniel Mack <zonque@gmail.com> wrote:
> On 04.10.2013 14:53, Ezequiel Garcia wrote:
>> Some rotary-encoder devices (such as those with detents) are capable
>> of producing a stable event on each step. This commit adds support
>> for this case, by implementing a new interruption handler.
>>
>> The handler needs only detect the direction of the turn and generate
>> an event according to this detection.
>
> I think you can squash patch 2/2 into this one. It doesn't make much
> sense to have a one-liner patch to just update the documenation separately.
>
> Other than that, the code looks fine to me.
>
>   Acked-by: Daniel Mack <zonque@gmail.com>
>

Could you merge these two patches?

It's already acked by Daniel, and there wasn't any other feedback
so I think we're ready to get them in and support more devices :-)

Patch
diff mbox series

diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
index 5b1aff8..6c7a554 100644
--- a/drivers/input/misc/rotary_encoder.c
+++ b/drivers/input/misc/rotary_encoder.c
@@ -117,6 +117,42 @@  static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t rotary_encoder_stepped_irq(int irq, void *dev_id)
+{
+	struct rotary_encoder *encoder = dev_id;
+	int state;
+	unsigned char sum;
+
+	state = rotary_encoder_get_state(encoder->pdata);
+
+	/*
+	 * We encode the previous and the current state using a byte.
+	 * The previous state in the MSB nibble, the current state in the LSB
+	 * nibble. Then use a table to decide the direction of the turn.
+	 */
+	sum = (encoder->last_stable << 4) + state;
+	switch (sum) {
+	case 0x31:
+	case 0x10:
+	case 0x02:
+	case 0x23:
+		encoder->dir = 0; /* clockwise */
+		break;
+	/*
+	 * TODO: Add the other case, and the illegal values should
+	 * say a WARN (it's a BUG, but we won't stop the kernel for it :)
+	 */
+	default:
+		encoder->dir = 1;
+	}
+
+	rotary_encoder_report_event(encoder);
+
+	encoder->last_stable = state;
+
+	return IRQ_HANDLED;
+}
+
 static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
 {
 	struct rotary_encoder *encoder = dev_id;
@@ -180,6 +216,8 @@  static struct rotary_encoder_platform_data *rotary_encoder_parse_dt(struct devic
 					"rotary-encoder,rollover", NULL);
 	pdata->half_period = !!of_get_property(np,
 					"rotary-encoder,half-period", NULL);
+	pdata->on_each_step = !!of_get_property(np,
+					"rotary-encoder,on-each-step", NULL);
 
 	return pdata;
 }
@@ -254,6 +292,9 @@  static int rotary_encoder_probe(struct platform_device *pdev)
 	if (pdata->half_period) {
 		handler = &rotary_encoder_half_period_irq;
 		encoder->last_stable = rotary_encoder_get_state(pdata);
+	} else if (pdata->on_each_step) {
+		handler = &rotary_encoder_stepped_irq;
+		encoder->last_stable = rotary_encoder_get_state(pdata);
 	} else {
 		handler = &rotary_encoder_irq;
 	}
diff --git a/include/linux/rotary_encoder.h b/include/linux/rotary_encoder.h
index 3f594dc..499f6f7 100644
--- a/include/linux/rotary_encoder.h
+++ b/include/linux/rotary_encoder.h
@@ -11,6 +11,7 @@  struct rotary_encoder_platform_data {
 	bool relative_axis;
 	bool rollover;
 	bool half_period;
+	bool on_each_step;
 };
 
 #endif /* __ROTARY_ENCODER_H__ */