[PATCH 3/3 v6] input: pwm-beeper: add feature to set volume level

[Manuel Traut <manuel.traut@mt.com>]

This patch adds the devicetree bindings to set the volume levels
and the default volume level.

Signed-off-by: Frieder Schrempf <frieder.schrempf@exceet.de>
---
 drivers/input/misc/pwm-beeper.c | 58 +++++++++++++++++++++++----------
 1 file changed, 41 insertions(+), 17 deletions(-)

diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
index fadc73e1c89a..f95d6b5899c7 100644
--- a/drivers/input/misc/pwm-beeper.c
+++ b/drivers/input/misc/pwm-beeper.c
@@ -181,8 +181,9 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 	struct pwm_beeper *beeper;
 	struct pwm_state state;
 	u32 bell_frequency;
-	int error;
+	int error, length;
 	size_t size;
+	u32 value;
 
 	beeper = devm_kzalloc(dev, sizeof(*beeper), GFP_KERNEL);
 	if (!beeper)
@@ -228,23 +229,46 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 
 	beeper->bell_frequency = bell_frequency;
 
-	beeper->max_volume = 4;
-
-	size = sizeof(*beeper->volume_levels) *
-		(beeper->max_volume + 1);
-
-	beeper->volume_levels = devm_kzalloc(&(pdev->dev), size,
-		GFP_KERNEL);
-	if (!beeper->volume_levels)
-		return -ENOMEM;
-
-	beeper->volume_levels[0] = 0;
-	beeper->volume_levels[1] = 8;
-	beeper->volume_levels[2] = 20;
-	beeper->volume_levels[3] = 40;
-	beeper->volume_levels[4] = 500;
+	/* determine the number of volume levels */
+	length = device_property_read_u32_array(&pdev->dev, "volume-levels", NULL, 0);
+	if (length <= 0) {
+		dev_dbg(&pdev->dev, "no volume levels specified, using max volume\n");
+		beeper->max_volume = 1;
+	} else
+		beeper->max_volume = length;
+
+	/* read volume levels from DT property */
+	if (beeper->max_volume > 0) {
+		size = sizeof(*beeper->volume_levels) *	beeper->max_volume;
+
+		beeper->volume_levels = devm_kzalloc(&(pdev->dev), size,
+			GFP_KERNEL);
+		if (!beeper->volume_levels)
+			return -ENOMEM;
+
+		if (length > 0) {
+			error = device_property_read_u32_array(&pdev->dev, "volume-levels",
+						beeper->volume_levels,
+						beeper->max_volume);
+
+			if (error < 0)
+				return error;
+
+			error = device_property_read_u32(&pdev->dev, "default-volume-level",
+						   &value);
+
+			if (error < 0) {
+				dev_dbg(&pdev->dev, "no default volume specified, using max volume\n");
+				value = beeper->max_volume - 1;
+			}
+		} else {
+			beeper->volume_levels[0] = 500;
+			value = 0;
+		}
 
-	beeper->volume = beeper->max_volume;
+		beeper->volume = value;
+		beeper->max_volume--;
+	}
 
 	beeper->input = devm_input_allocate_device(dev);
 	if (!beeper->input) {
-- 
2.39.0