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path: root/drivers/input/misc/rotary_encoder.c
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Diffstat (limited to 'drivers/input/misc/rotary_encoder.c')
-rw-r--r--drivers/input/misc/rotary_encoder.c129
1 files changed, 120 insertions, 9 deletions
diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
index f27f81ee84ed..8aee71986430 100644
--- a/drivers/input/misc/rotary_encoder.c
+++ b/drivers/input/misc/rotary_encoder.c
@@ -26,6 +26,7 @@
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>
+#include <linux/pm.h>
#define DRV_NAME "rotary-encoder"
@@ -142,6 +143,55 @@ 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", },
@@ -156,6 +206,7 @@ static struct rotary_encoder_platform_data *rotary_encoder_parse_dt(struct devic
struct device_node *np = dev->of_node;
struct rotary_encoder_platform_data *pdata;
enum of_gpio_flags flags;
+ int error;
if (!of_id || !np)
return NULL;
@@ -174,12 +225,27 @@ static struct rotary_encoder_platform_data *rotary_encoder_parse_dt(struct devic
pdata->gpio_b = of_get_gpio_flags(np, 1, &flags);
pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW;
- pdata->relative_axis = !!of_get_property(np,
- "rotary-encoder,relative-axis", NULL);
- pdata->rollover = !!of_get_property(np,
- "rotary-encoder,rollover", NULL);
- pdata->half_period = !!of_get_property(np,
- "rotary-encoder,half-period", NULL);
+ pdata->relative_axis =
+ of_property_read_bool(np, "rotary-encoder,relative-axis");
+ pdata->rollover = of_property_read_bool(np, "rotary-encoder,rollover");
+
+ error = of_property_read_u32(np, "rotary-encoder,steps-per-period",
+ &pdata->steps_per_period);
+ if (error) {
+ /*
+ * The 'half-period' property has been deprecated, you must use
+ * 'steps-per-period' and set an appropriate value, but we still
+ * need to parse it to maintain compatibility.
+ */
+ if (of_property_read_bool(np, "rotary-encoder,half-period")) {
+ pdata->steps_per_period = 2;
+ } else {
+ /* Fallback to one step per period behavior */
+ pdata->steps_per_period = 1;
+ }
+ }
+
+ pdata->wakeup_source = of_property_read_bool(np, "wakeup-source");
return pdata;
}
@@ -250,12 +316,23 @@ 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,
@@ -280,6 +357,8 @@ static int rotary_encoder_probe(struct platform_device *pdev)
goto exit_free_irq_b;
}
+ device_init_wakeup(&pdev->dev, pdata->wakeup_source);
+
platform_set_drvdata(pdev, encoder);
return 0;
@@ -306,6 +385,8 @@ static int rotary_encoder_remove(struct platform_device *pdev)
struct rotary_encoder *encoder = platform_get_drvdata(pdev);
const struct rotary_encoder_platform_data *pdata = encoder->pdata;
+ device_init_wakeup(&pdev->dev, false);
+
free_irq(encoder->irq_a, encoder);
free_irq(encoder->irq_b, encoder);
gpio_free(pdata->gpio_a);
@@ -320,11 +401,41 @@ static int rotary_encoder_remove(struct platform_device *pdev)
return 0;
}
+#ifdef CONFIG_PM_SLEEP
+static int rotary_encoder_suspend(struct device *dev)
+{
+ struct rotary_encoder *encoder = dev_get_drvdata(dev);
+
+ if (device_may_wakeup(dev)) {
+ enable_irq_wake(encoder->irq_a);
+ enable_irq_wake(encoder->irq_b);
+ }
+
+ return 0;
+}
+
+static int rotary_encoder_resume(struct device *dev)
+{
+ struct rotary_encoder *encoder = dev_get_drvdata(dev);
+
+ if (device_may_wakeup(dev)) {
+ disable_irq_wake(encoder->irq_a);
+ disable_irq_wake(encoder->irq_b);
+ }
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(rotary_encoder_pm_ops,
+ rotary_encoder_suspend, rotary_encoder_resume);
+
static struct platform_driver rotary_encoder_driver = {
.probe = rotary_encoder_probe,
.remove = rotary_encoder_remove,
.driver = {
.name = DRV_NAME,
+ .pm = &rotary_encoder_pm_ops,
.of_match_table = of_match_ptr(rotary_encoder_of_match),
}
};