This adds a device tree node for sound on LEGO MINDSTORMS EV3. The EV3
uses one of the SoC PWMs connected to an amplifier to create sound from
a speaker.
The PWM is passed through a low-pass filter, so it is actually possible
to do PCM playback, but there is no existing driver, so just using
pwm-beeper for now, since it is also a compatible mode of operation.
Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx>
---
arch/arm/boot/dts/da850-lego-ev3.dts | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/arch/arm/boot/dts/da850-lego-ev3.dts b/arch/arm/boot/dts/da850-lego-ev3.dts
index 0309537..c20580a 100644
--- a/arch/arm/boot/dts/da850-lego-ev3.dts
+++ b/arch/arm/boot/dts/da850-lego-ev3.dts
@@ -123,6 +123,14 @@
pinctrl-0 = <&system_power_pin>;
};
+ sound {
+ compatible = "pwm-beeper";
+ pinctrl-names = "default";
+ pinctrl-0 = <&ehrpwm0b_pins>;
+ pwms = <&ehrpwm0 1 1000000 0>;
+ amp-supply = <&>;
+ };
+
/*
* This is a 5V current limiting regulator that is shared by USB,
* the sensor (input) ports, the motor (output) ports and the A/DC.
@@ -152,6 +160,18 @@
regulator-boot-on;
vin-supply = <&vcc5v>;
};
+
+ /*
+ * This is the amplifier for the speaker.
+ */
+ amp: regulator3 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&_pins>;
+ compatible = "regulator-fixed";
+ regulator-name = "amp";
+ gpio = <&gpio 111 GPIO_ACTIVE_HIGH>;
+ enable-active-high;
+ };
};
&pmx_core {
@@ -208,6 +228,13 @@
0x4c 0x00008000 0x0000f000
>;
};
+
+ amp_pins: pinmux_amp_pins {
+ pinctrl-single,bits = <
+ /* GP6[15] */
+ 0x34 0x00000008 0x0000000f
+ >;
+ };
};
&pinconf {
@@ -316,6 +343,10 @@
};
};
+&ehrpwm0 {
+ status = "okay";
+};
+
&gpio {
status = "okay";
};
--
2.7.4
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