Input: pwm-beeper - support customized freq for SND_BELL

Extend the pwm-beeper driver to support customized frequency for SND_BELL
from device properties.

Signed-off-by: Guan Ben <[e-mail]>
Signed-off-by: Mark Jonas <[e-mail]>
Signed-off-by: Heiko Schocher <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/devicetree/bindings/input/pwm-beeper.txt

···
 
 Optional properties:
 - amp-supply: phandle to a regulator that acts as an amplifier for the beeper
+- beeper-hz:  bell frequency in Hz
 
 Example:
 

drivers/input/misc/pwm-beeper.c

···
 #include <linux/kernel.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/property.h>
 #include <linux/pwm.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
···
 	struct regulator *amplifier;
 	struct work_struct work;
 	unsigned long period;
+	unsigned int bell_frequency;
 	bool suspended;
 	bool amplifier_on;
 };
···
 
 	switch (code) {
 	case SND_BELL:
-		value = value ? 1000 : 0;
+		value = value ? beeper->bell_frequency : 0;
 		break;
 	case SND_TONE:
 		break;
···
 	struct device *dev = &pdev->dev;
 	struct pwm_beeper *beeper;
 	struct pwm_state state;
+	u32 bell_frequency;
 	int error;
 
 	beeper = devm_kzalloc(dev, sizeof(*beeper), GFP_KERNEL);
···
 	}
 
 	INIT_WORK(&beeper->work, pwm_beeper_work);
+
+	error = device_property_read_u32(dev, "beeper-hz", &bell_frequency);
+	if (error) {
+		bell_frequency = 1000;
+		dev_dbg(dev,
+			"failed to parse 'beeper-hz' property, using default: %uHz\n",
+			bell_frequency);
+	}
+
+	beeper->bell_frequency = bell_frequency;
 
 	beeper->input = devm_input_allocate_device(dev);
 	if (!beeper->input) {