[PATCH v2] Input: pwm-beeper: support customized freq for SND_BELL

[Heiko Schocher]

From: Guan Ben <ben.guan@xxxxxxxxxxxx>

extend the pwm-beeper driver to support customized frequency
for SND_BELL from device tree.

Signed-off-by: Guan Ben <ben.guan@xxxxxxxxxxxx>
Signed-off-by: Mark Jonas <mark.jonas@xxxxxxxxxxxx>
[hs@xxxxxxx: adapted to 4.10-rc7]
Signed-off-by: Heiko Schocher <hs@xxxxxxx>

---

Changes in v2:
- add comment from Rob Herring:
  rename property name "bell-frequency" to "beeper-hz"
- add comment from Dmitry Torokhov:
  use device_property_read_u32() instead of of_property_read_u32()
- rebased against c470abd4fde40ea6a0846a2beab642a578c0b8cd
  Linux 4.10

 .../devicetree/bindings/input/pwm-beeper.txt       |  3 ++
 drivers/input/misc/pwm-beeper.c                    | 36 ++++++++++++++++------
 2 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.txt b/Documentation/devicetree/bindings/input/pwm-beeper.txt
index be332ae..4e4e128 100644
--- a/Documentation/devicetree/bindings/input/pwm-beeper.txt
+++ b/Documentation/devicetree/bindings/input/pwm-beeper.txt
@@ -5,3 +5,6 @@ Registers a PWM device as beeper.
 Required properties:
 - compatible: should be "pwm-beeper"
 - pwms: phandle to the physical PWM device
+
+optional properties:
+- beeper-hz:  bell frequency in Hz
diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
index 5f9655d..5ea6fda 100644
--- a/drivers/input/misc/pwm-beeper.c
+++ b/drivers/input/misc/pwm-beeper.c
@@ -27,6 +27,7 @@ struct pwm_beeper {
 	struct pwm_device *pwm;
 	struct work_struct work;
 	unsigned long period;
+	unsigned int bell_frequency;
 };
 
 #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
@@ -58,20 +59,17 @@ static int pwm_beeper_event(struct input_dev *input,
 	if (type != EV_SND || value < 0)
 		return -EINVAL;
 
-	switch (code) {
-	case SND_BELL:
-		value = value ? 1000 : 0;
-		break;
-	case SND_TONE:
-		break;
-	default:
+	if (code != SND_BELL && code != SND_TONE)
 		return -EINVAL;
-	}
 
 	if (value == 0)
 		beeper->period = 0;
-	else
+	else {
+		if (code == SND_BELL)
+			value = beeper->bell_frequency;
+
 		beeper->period = HZ_TO_NANOSECONDS(value);
+	}
 
 	schedule_work(&beeper->work);
 
@@ -93,6 +91,25 @@ static void pwm_beeper_close(struct input_dev *input)
 	pwm_beeper_stop(beeper);
 }
 
+static void pwm_beeper_init_bell_frequency(struct device *dev,
+					   struct pwm_beeper *beeper)
+{
+	struct device_node *node;
+	unsigned int bell_frequency = 1000;
+	int err;
+
+	if (IS_ENABLED(CONFIG_OF)) {
+		node = dev->of_node;
+		err = device_property_read_u32(dev, "beeper-hz",
+					       &bell_frequency);
+		if (err < 0)
+			dev_dbg(dev, "Failed to read beeper-hz, using default: %u Hz\n",
+				bell_frequency);
+	}
+
+	beeper->bell_frequency = bell_frequency;
+}
+
 static int pwm_beeper_probe(struct platform_device *pdev)
 {
 	unsigned long pwm_id = (unsigned long)dev_get_platdata(&pdev->dev);
@@ -122,6 +139,7 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 	pwm_apply_args(beeper->pwm);
 
 	INIT_WORK(&beeper->work, pwm_beeper_work);
+	pwm_beeper_init_bell_frequency(&pdev->dev, beeper);
 
 	beeper->input = input_allocate_device();
 	if (!beeper->input) {
-- 
2.7.4