1 files changed, 116 insertions, 0 deletions
diff --git a/drivers/sound/pwm-beeper.c b/drivers/sound/pwm-beeper.c
new file mode 100644
index 0000000000..94b27359c1
--- /dev/null
+++ b/drivers/sound/pwm-beeper.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
+ *  Copyright (C) 2021, Ahmad Fatoum
+ */
+
+#include <common.h>
+#include <regulator.h>
+#include <sound.h>
+#include <of.h>
+#include <pwm.h>
+
+struct pwm_beeper {
+	struct pwm_device *pwm;
+	struct regulator *amplifier;
+	struct sound_card card;
+};
+
+#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
+
+static int pwm_beeper_beep(struct sound_card *card, unsigned freq, unsigned duration)
+{
+	struct pwm_beeper *beeper = container_of(card, struct pwm_beeper, card);
+	struct pwm_state state;
+	int error = 0;
+
+	if (!freq) {
+		regulator_disable(beeper->amplifier);
+		goto pwm_disable;
+	}
+
+	pwm_get_state(beeper->pwm, &state);
+
+	state.enabled = true;
+	state.period = HZ_TO_NANOSECONDS(freq);
+	pwm_set_relative_duty_cycle(&state, 50, 100);
+
+	error = pwm_apply_state(beeper->pwm, &state);
+	if (error)
+		return error;
+
+	error = regulator_enable(beeper->amplifier);
+	if (error)
+		goto pwm_disable;
+
+	return 0;
+pwm_disable:
+	pwm_disable(beeper->pwm);
+	return error;
+}
+
+static int pwm_beeper_probe(struct device *dev)
+{
+	struct pwm_beeper *beeper;
+	struct sound_card *card;
+	struct pwm_state state;
+	u32 bell_frequency;
+	int error;
+
+	beeper = xzalloc(sizeof(*beeper));
+	dev->priv = beeper;
+
+	beeper->pwm = of_pwm_request(dev->of_node, NULL);
+	if (IS_ERR(beeper->pwm))
+		return dev_errp_probe(dev, beeper->pwm, "requesting PWM device\n");
+
+	/* Sync up PWM state and ensure it is off. */
+	pwm_init_state(beeper->pwm, &state);
+	state.enabled = false;
+	error = pwm_apply_state(beeper->pwm, &state);
+	if (error) {
+		dev_err(dev, "failed to apply initial PWM state: %d\n",
+			error);
+		return error;
+	}
+
+	beeper->amplifier = regulator_get(dev, "amp");
+	if (IS_ERR(beeper->amplifier))
+		return dev_errp_probe(dev, beeper->amplifier, "getting 'amp' regulator\n");
+
+	error = of_property_read_u32(dev->of_node, "beeper-hz",
+				     &bell_frequency);
+	if (error) {
+		bell_frequency = 1000;
+		dev_dbg(dev, "failed to parse 'beeper-hz' property, using default: %uHz\n",
+			bell_frequency);
+	}
+
+	card = &beeper->card;
+	card->name = dev->of_node->full_name;
+	card->bell_frequency = bell_frequency;
+	card->beep = pwm_beeper_beep;
+
+	return sound_card_register(card);
+}
+
+static void pwm_beeper_suspend(struct device *dev)
+{
+	struct pwm_beeper *beeper = dev->priv;
+
+	pwm_beeper_beep(&beeper->card, 0, 0);
+}
+
+static const struct of_device_id pwm_beeper_match[] = {
+	{ .compatible = "pwm-beeper", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, pwm_beeper_match);
+
+static struct driver pwm_beeper_driver = {
+	.name		= "pwm-beeper",
+	.probe		= pwm_beeper_probe,
+	.remove		= pwm_beeper_suspend,
+	.of_compatible	= pwm_beeper_match,
+};
+device_platform_driver(pwm_beeper_driver);