From: Lars-Peter Clausen on
This patch adds a simple driver which allows to use pwm based beepers (for
example piezo elements) as a pcspkr-like device.

Signed-off-by: Lars-Peter Clausen <lars(a)metafoo.de>
---
drivers/input/misc/Kconfig | 11 ++
drivers/input/misc/Makefile | 2 +-
drivers/input/misc/pwm-beeper.c | 197 +++++++++++++++++++++++++++++++++++++++
3 files changed, 209 insertions(+), 1 deletions(-)
create mode 100644 drivers/input/misc/pwm-beeper.c

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index ede6d52..068f250 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -427,4 +427,15 @@ config INPUT_ADXL34X_SPI
To compile this driver as a module, choose M here: the
module will be called adxl34x-spi.

+config INPUT_PWM_BEEPER
+ tristate "PWM beeper support"
+ depends on HAVE_PWM
+ help
+ Say Y here to get support for PWM based beeper devices.
+
+ If unsure, say N.
+
+ To compile this driver as a module, choose M here: the module will be
+ called pwm-beeper
+
endif
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 97b5dc3..1df6c55 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_INPUT_PCF50633_PMU) += pcf50633-input.o
obj-$(CONFIG_INPUT_PCF8574) += pcf8574_keypad.o
obj-$(CONFIG_INPUT_PCSPKR) += pcspkr.o
obj-$(CONFIG_INPUT_POWERMATE) += powermate.o
+obj-$(CONFIG_INPUT_PWM_BEEPER) += pwm-beeper.o
obj-$(CONFIG_INPUT_RB532_BUTTON) += rb532_button.o
obj-$(CONFIG_INPUT_GPIO_ROTARY_ENCODER) += rotary_encoder.o
obj-$(CONFIG_INPUT_SGI_BTNS) += sgi_btns.o
@@ -40,4 +41,3 @@ obj-$(CONFIG_INPUT_WINBOND_CIR) += winbond-cir.o
obj-$(CONFIG_INPUT_WISTRON_BTNS) += wistron_btns.o
obj-$(CONFIG_INPUT_WM831X_ON) += wm831x-on.o
obj-$(CONFIG_INPUT_YEALINK) += yealink.o
-
diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
new file mode 100644
index 0000000..8f5321f
--- /dev/null
+++ b/drivers/input/misc/pwm-beeper.c
@@ -0,0 +1,197 @@
+/*
+ * Copyright (C) 2010, Lars-Peter Clausen <lars(a)metafoo.de>
+ * PWM beeper driver
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+struct pwm_beeper {
+ struct input_dev *input;
+ struct pwm_device *pwm;
+ unsigned long period;
+};
+
+#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
+
+static int pwm_beeper_event(struct input_dev *input, unsigned int type,
+ unsigned int code, int value)
+{
+ int ret = 0;
+ struct pwm_beeper *beeper = input_get_drvdata(input);
+ unsigned long period;
+
+ if (type != EV_SND || value < 0)
+ return -EINVAL;
+
+ switch (code) {
+ case SND_BELL:
+ value = value ? 1000 : 0;
+ break;
+ case SND_TONE:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (value == 0) {
+ pwm_config(beeper->pwm, 0, 0);
+ pwm_disable(beeper->pwm);
+ } else {
+ period = HZ_TO_NANOSECONDS(value);
+ ret = pwm_config(beeper->pwm, period / 2, period);
+ if (ret)
+ return ret;
+ ret = pwm_enable(beeper->pwm);
+ if (ret)
+ return ret;
+ beeper->period = period;
+ }
+
+ return 0;
+}
+
+static int __devinit pwm_beeper_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct pwm_beeper *beeper;
+ unsigned long pwm_id = (unsigned long)pdev->dev.platform_data;
+
+ beeper = kzalloc(sizeof(*beeper), GFP_KERNEL);
+ if (!beeper)
+ return -ENOMEM;
+
+ beeper->pwm = pwm_request(pwm_id, "pwm beeper");
+
+ if (IS_ERR(beeper->pwm)) {
+ ret = PTR_ERR(beeper->pwm);
+ dev_err(&pdev->dev, "Failed to request pwm device: %d\n", ret);
+ goto err_free;
+ }
+
+ beeper->input = input_allocate_device();
+ if (!beeper->input) {
+ dev_err(&pdev->dev, "Failed to allocate input device\n");
+ ret = -ENOMEM;
+ goto err_pwm_free;
+ }
+ beeper->input->dev.parent = &pdev->dev;
+
+ beeper->input->name = "pwm-beeper";
+ beeper->input->phys = "pwm/input0";
+ beeper->input->id.bustype = BUS_HOST;
+ beeper->input->id.vendor = 0x001f;
+ beeper->input->id.product = 0x0001;
+ beeper->input->id.version = 0x0100;
+
+ beeper->input->evbit[0] = BIT(EV_SND);
+ beeper->input->sndbit[0] = BIT(SND_TONE) | BIT(SND_BELL);
+
+ beeper->input->event = pwm_beeper_event;
+
+ input_set_drvdata(beeper->input, beeper);
+ ret = input_register_device(beeper->input);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to register input device: %d\n", ret);
+ goto err_input_free;
+ }
+
+ platform_set_drvdata(pdev, beeper);
+
+ return 0;
+
+err_input_free:
+ input_free_device(beeper->input);
+err_pwm_free:
+ pwm_free(beeper->pwm);
+err_free:
+ kfree(beeper);
+
+ return ret;
+}
+
+static int __devexit pwm_beeper_remove(struct platform_device *pdev)
+{
+ struct pwm_beeper *beeper = platform_get_drvdata(pdev);
+
+ platform_set_drvdata(pdev, NULL);
+ input_unregister_device(beeper->input);
+
+ pwm_disable(beeper->pwm);
+ pwm_free(beeper->pwm);
+
+ kfree(beeper);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int pwm_beeper_suspend(struct device *dev)
+{
+ struct pwm_beeper *beeper = dev_get_drvdata(dev);
+ if (beeper->period)
+ pwm_disable(beeper->pwm);
+
+ return 0;
+}
+
+static int pwm_beeper_resume(struct device *dev)
+{
+ struct pwm_beeper *beeper = dev_get_drvdata(dev);
+
+ if (beeper->period) {
+ pwm_config(beeper->pwm, beeper->period / 2, beeper->period);
+ pwm_enable(beeper->pwm);
+ }
+
+ return 0;
+}
+
+static const SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
+ pwm_beeper_suspend, pwm_beeper_resume);
+
+#define PWM_BEEPER_PM_OPS (&pwm_beeper_pm_ops)
+#else
+#define PWM_BEEPER_PM_OPS NULL
+#endif
+
+static struct platform_driver pwm_beeper_driver = {
+ .probe = pwm_beeper_probe,
+ .remove = __devexit_p(pwm_beeper_remove),
+ .driver = {
+ .name = "pwm-beeper",
+ .owner = THIS_MODULE,
+ .pm = PWM_BEEPER_PM_OPS,
+ },
+};
+
+static int __init pwm_beeper_init(void)
+{
+ return platform_driver_register(&pwm_beeper_driver);
+}
+module_init(pwm_beeper_init);
+
+static void __exit pwm_beeper_exit(void)
+{
+ platform_driver_unregister(&pwm_beeper_driver);
+}
+module_exit(pwm_beeper_exit);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars(a)metafoo.de>");
+MODULE_DESCRIPTION("PWM beeper driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:pwm-beeper");
--
1.5.6.5

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