Re: [PATCH v2 1/2] Input: rotary-encoder: Add 'stepped' irq handler

From: Daniel Mack
Date: Fri Oct 04 2013 - 09:18:47 EST


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@xxxxxxxxx>


Thanks,
Daniel


>
> Cc: Daniel Mack <zonque@xxxxxxxxx>
> Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxxxxxxxxx>
> ---
> 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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