This is poor man's solution for those who cannot use pwm-beeper.
Beeper pin is driven by hrtimer, so hearable jitter is expected,
but should be acceptable for frequencies under 1kHz. This mode
is enabled by adding 'beeper-hz' node property.
Signed-off-by: Ladislav Michl <ladis@xxxxxxxxxxxxxx>
---
.../devicetree/bindings/input/gpio-beeper.txt | 5 ++
drivers/input/misc/gpio-beeper.c | 92 +++++++++++++++++++---
2 files changed, 87 insertions(+), 10 deletions(-)
diff --git a/Documentation/devicetree/bindings/input/gpio-beeper.txt b/Documentation/devicetree/bindings/input/gpio-beeper.txt
index a5086e37fce6..855f8cf8af10 100644
--- a/Documentation/devicetree/bindings/input/gpio-beeper.txt
+++ b/Documentation/devicetree/bindings/input/gpio-beeper.txt
@@ -6,6 +6,11 @@ Required properties:
- compatible: Should be "gpio-beeper".
- gpios: From common gpio binding; gpio connection to beeper enable pin.
+Optional properties:
+- beeper-hz: Bell frequency in Hz. This option enables hrtimer driven beeper
+ pin toggle. This is only good for poorly designed hardware
+ where PWM cannot be used as there always be hearable jitter.
+
Example:
beeper: beeper {
compatible = "gpio-beeper";
diff --git a/drivers/input/misc/gpio-beeper.c b/drivers/input/misc/gpio-beeper.c
index 409c85da71c3..37f22884e967 100644
--- a/drivers/input/misc/gpio-beeper.c
+++ b/drivers/input/misc/gpio-beeper.c
@@ -12,6 +12,7 @@
#include <linux/input.h>
#include <linux/module.h>
#include <linux/gpio/consumer.h>
+#include <linux/hrtimer.h>
#include <linux/of.h>
#include <linux/workqueue.h>
#include <linux/platform_device.h>
@@ -20,11 +21,19 @@
struct gpio_beeper {
struct work_struct work;
+ struct hrtimer timer;
struct gpio_desc *desc;
- bool beeping;
+ ktime_t tick;
+ unsigned int bell_freq;
+ int on;
};
-static void gpio_beeper_toggle(struct gpio_beeper *beep, bool on)
+static void gpio_beeper_toggle(struct gpio_beeper *beep, int on)
+{
+ gpiod_set_value(beep->desc, on);
+}
+
+static void gpio_beeper_toggle_cansleep(struct gpio_beeper *beep, int on)
{
gpiod_set_value_cansleep(beep->desc, on);
}
@@ -33,7 +42,17 @@ static void gpio_beeper_work(struct work_struct *work)
{
struct gpio_beeper *beep = container_of(work, struct gpio_beeper, work);
- gpio_beeper_toggle(beep, beep->beeping);
+ gpio_beeper_toggle_cansleep(beep, beep->on);
+}
+
+static enum hrtimer_restart gpio_beeper_timer(struct hrtimer *timer)
+{
+ struct gpio_beeper *beep = container_of(timer, struct gpio_beeper, timer);
+
+ beep->on = !beep->on;
+ gpio_beeper_toggle(beep, beep->on);
+ hrtimer_forward_now(timer, beep->tick);
+ return HRTIMER_RESTART;
}
static int gpio_beeper_event(struct input_dev *dev, unsigned int type,
@@ -47,19 +66,59 @@ static int gpio_beeper_event(struct input_dev *dev, unsigned int type,
if (value < 0)
return -EINVAL;
- beep->beeping = value;
+ beep->on = value;
/* Schedule work to actually turn the beeper on or off */
schedule_work(&beep->work);
return 0;
}
+static int gpio_beeper_tone_event(struct input_dev *dev, unsigned int type,
+ unsigned int code, int value)
+{
+ struct gpio_beeper *beep = input_get_drvdata(dev);
+
+ if (type != EV_SND)
+ return -ENOTSUPP;
+
+ switch (code) {
+ case SND_BELL:
+ value = value ? beep->bell_freq : 0;
+ break;
+ case SND_TONE:
+ break;
+ default:
+ return -ENOTSUPP;
+ }
+
+ if (value < 0)
+ return -EINVAL;
+
+ if (value) {
+ beep->tick = ns_to_ktime(1000000000UL / 2 / value);
+ hrtimer_start(&beep->timer, ns_to_ktime(0), HRTIMER_MODE_REL);
+ } else {
+ hrtimer_cancel(&beep->timer);
+ gpio_beeper_toggle(beep, 0);
+ }
+
+ return 0;
+}
+
static void gpio_beeper_close(struct input_dev *input)
{
struct gpio_beeper *beep = input_get_drvdata(input);
cancel_work_sync(&beep->work);
- gpio_beeper_toggle(beep, false);
+ gpio_beeper_toggle_cansleep(beep, 0);
+}
+
+static void gpio_beeper_tone_close(struct input_dev *input)
+{
+ struct gpio_beeper *beep = input_get_drvdata(input);
+
+ hrtimer_cancel(&beep->timer);
+ gpio_beeper_toggle_cansleep(beep, 0);
}
static int gpio_beeper_probe(struct platform_device *pdev)
@@ -80,18 +139,31 @@ static int gpio_beeper_probe(struct platform_device *pdev)
if (!input)
return -ENOMEM;
- INIT_WORK(&beep->work, gpio_beeper_work);
-
input->name = pdev->name;
input->id.bustype = BUS_HOST;
input->id.vendor = 0x0001;
input->id.product = 0x0001;
input->id.version = 0x0100;
- input->close = gpio_beeper_close;
- input->event = gpio_beeper_event;
-
input_set_capability(input, EV_SND, SND_BELL);
+ if (device_property_read_u32(dev, "beeper-hz", &beep->bell_freq)) {
+ input->close = gpio_beeper_close;
+ input->event = gpio_beeper_event;
+
+ INIT_WORK(&beep->work, gpio_beeper_work);
+ } else {
+ dev_dbg(dev,
+ "tone mode enabled using default frequency: %uHz\n",
+ beep->bell_freq);
+
+ input->close = gpio_beeper_tone_close;
+ input->event = gpio_beeper_tone_event;
+ input_set_capability(input, EV_SND, SND_TONE);
+
+ hrtimer_init(&beep->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ beep->timer.function = gpio_beeper_timer;
+ }
+
input_set_drvdata(input, beep);
return input_register_device(input);
--
2.15.0
--
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