Input: Add pwm beeper driver

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@metafoo.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

3 files changed, 211 insertions, 0 deletions

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index ede6d52fe95c..b49e23379723 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -327,6 +327,17 @@ config INPUT_PCF8574
           To compile this driver as a module, choose M here: the
           module will be called pcf8574_keypad.
 
+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.
+
 config INPUT_GPIO_ROTARY_ENCODER
         tristate "Rotary encoders connected to GPIO pins"
         depends on GPIOLIB && GENERIC_GPIO
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 97b5dc32df19..19ccca78fa76 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
diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
new file mode 100644
index 000000000000..57c294f07198
--- /dev/null
+++ b/drivers/input/misc/pwm-beeper.c
@@ -0,0 +1,199 @@
+/*
+ *  Copyright (C) 2010, Lars-Peter Clausen <lars@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)
+{
+        unsigned long pwm_id = (unsigned long)pdev->dev.platform_data;
+        struct pwm_beeper *beeper;
+        int error;
+
+        beeper = kzalloc(sizeof(*beeper), GFP_KERNEL);
+        if (!beeper)
+                return -ENOMEM;
+
+        beeper->pwm = pwm_request(pwm_id, "pwm beeper");
+
+        if (IS_ERR(beeper->pwm)) {
+                error = PTR_ERR(beeper->pwm);
+                dev_err(&pdev->dev, "Failed to request pwm device: %d\n", error);
+                goto err_free;
+        }
+
+        beeper->input = input_allocate_device();
+        if (!beeper->input) {
+                dev_err(&pdev->dev, "Failed to allocate input device\n");
+                error = -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);
+
+        error = input_register_device(beeper->input);
+        if (error) {
+                dev_err(&pdev->dev, "Failed to register input device: %d\n", error);
+                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 error;
+}
+
+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 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@metafoo.de>");
+MODULE_DESCRIPTION("PWM beeper driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:pwm-beeper");