As per the recent devicetree binding changes, this commit adds the
support for the new 'steps-per-period' property.
Legacy properties to specify the rotary behavior, are now deprecated
and instead the new 'steps-per-period' is supported. The default behavior
is retained.
This allows to support rotary-encoder devices with detents wich are capable
of producing a stable event on each step.
Signed-off-by: Guido Martínez <guido@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxxxxxxxxx>
---
drivers/input/misc/rotary_encoder.c | 87 +++++++++++++++++++++++++++++++++++--
include/linux/rotary_encoder.h | 2 +-
2 files changed, 84 insertions(+), 5 deletions(-)
diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
index 15a4cc670a3f..e021615dd3c0 100644
--- a/drivers/input/misc/rotary_encoder.c
+++ b/drivers/input/misc/rotary_encoder.c
@@ -142,6 +142,55 @@ static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static irqreturn_t rotary_encoder_quarter_period_irq(int irq, void *dev_id)
+{
+ struct rotary_encoder *encoder = dev_id;
+ unsigned char sum;
+ int state;
+
+ 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;
+
+ case 0x13:
+ case 0x01:
+ case 0x20:
+ case 0x32:
+ encoder->dir = 1; /* counter-clockwise */
+ break;
+
+ default:
+ /*
+ * Ignore all other values. This covers the case when the
+ * state didn't change (a spurious interrupt) and the
+ * cases where the state changed by two steps, making it
+ * impossible to tell the direction.
+ *
+ * In either case, don't report any event and save the
+ * state for later.
+ */
+ goto out;
+ }
+
+ rotary_encoder_report_event(encoder);
+
+out:
+ encoder->last_stable = state;
+ return IRQ_HANDLED;
+}
+
#ifdef CONFIG_OF
static const struct of_device_id rotary_encoder_of_match[] = {
{ .compatible = "rotary-encoder", },
@@ -176,7 +225,26 @@ static struct rotary_encoder_platform_data *rotary_encoder_parse_dt(struct devic
pdata->relative_axis = of_property_read_bool(np, "rotary-encoder,relative-axis");
pdata->rollover = of_property_read_bool(np, "rotary-encoder,rollover");
- pdata->half_period = of_property_read_bool(np, "rotary-encoder,half-period");
+
+ if (!of_get_property(np, "rotary-encoder,steps-per-period", NULL)) {
+ /*
+ * Fallback to a one step per period behavior if the
+ * 'steps-per-period' is not set.
+ */
+ pdata->steps_per_period = 1;
+ } else {
+ of_property_read_u32(np, "rotary-encoder,steps-per-period",
+ &pdata->steps_per_period);
+ }
+
+ /*
+ * The 'half-period' property has been deprecated, you must use
+ * 'steps-per-period' and set an appropriate value.
+ */
+ if (of_get_property(np, "rotary-encoder,half-period", NULL)) {
+ pr_warn(FW_WARN "\"rotary-encoder,half-period\" is deprecated\n");
+ pdata->steps_per_period = 2;
+ }
return pdata;
}
@@ -247,12 +315,23 @@ static int rotary_encoder_probe(struct platform_device *pdev)
encoder->irq_a = gpio_to_irq(pdata->gpio_a);
encoder->irq_b = gpio_to_irq(pdata->gpio_b);
- /* request the IRQs */
- if (pdata->half_period) {
+ switch (pdata->steps_per_period) {
+ case 4:
+ handler = &rotary_encoder_quarter_period_irq;
+ encoder->last_stable = rotary_encoder_get_state(pdata);
+ break;
+ case 2:
handler = &rotary_encoder_half_period_irq;
encoder->last_stable = rotary_encoder_get_state(pdata);
- } else {
+ break;
+ case 1:
handler = &rotary_encoder_irq;
+ break;
+ default:
+ dev_err(dev, "'%d' is not a valid steps-per-period value\n",
+ pdata->steps_per_period);
+ err = -EINVAL;
+ goto exit_free_gpio_b;
}
err = request_irq(encoder->irq_a, handler,
diff --git a/include/linux/rotary_encoder.h b/include/linux/rotary_encoder.h
index 3f594dce5716..0bebba31908c 100644
--- a/include/linux/rotary_encoder.h
+++ b/include/linux/rotary_encoder.h
@@ -10,7 +10,7 @@ struct rotary_encoder_platform_data {
unsigned int inverted_b;
bool relative_axis;
bool rollover;
- bool half_period;
+ unsigned int steps_per_period;
};
#endif /* __ROTARY_ENCODER_H__ */
--
2.5.2
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