From 9e54924432783bfb21e905e0bf7042556bcb4b90 Mon Sep 17 00:00:00 2001 From: David Lechner Date: Sun, 15 Jan 2017 17:09:43 -0800 Subject: [PATCH] Input: pwm-beeper - add optional amplifier regulator This adds an optional regulator to the pwm-beeper device. This regulator acts as an amplifier. The amplifier is only enabled while beeping in order to reduce power consumption. Tested on LEGO MINDSTORMS EV3, which has a speaker connected to PWM through an amplifier. Signed-off-by: David Lechner Acked-by: Rob Herring Signed-off-by: Dmitry Torokhov --- .../devicetree/bindings/input/pwm-beeper.txt | 16 +++++ drivers/input/misc/pwm-beeper.c | 63 +++++++++++++++---- 2 files changed, 66 insertions(+), 13 deletions(-) diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.txt b/Documentation/devicetree/bindings/input/pwm-beeper.txt index be332ae4f2d6..529408b4431a 100644 --- a/Documentation/devicetree/bindings/input/pwm-beeper.txt +++ b/Documentation/devicetree/bindings/input/pwm-beeper.txt @@ -5,3 +5,19 @@ Registers a PWM device as beeper. Required properties: - compatible: should be "pwm-beeper" - pwms: phandle to the physical PWM device + +Optional properties: +- amp-supply: phandle to a regulator that acts as an amplifier for the beeper + +Example: + +beeper_amp: amplifier { + compatible = "fixed-regulator"; + gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>; +}; + +beeper { + compatible = "pwm-beeper"; + pwms = <&pwm0>; + amp-supply = <&beeper_amp>; +}; diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c index 069d594554bd..ad9b231e8468 100644 --- a/drivers/input/misc/pwm-beeper.c +++ b/drivers/input/misc/pwm-beeper.c @@ -14,6 +14,7 @@ */ #include +#include #include #include #include @@ -25,30 +26,59 @@ struct pwm_beeper { struct input_dev *input; struct pwm_device *pwm; + struct regulator *amplifier; struct work_struct work; unsigned long period; bool suspended; + bool amplifier_on; }; #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x)) -static void __pwm_beeper_set(struct pwm_beeper *beeper) +static int pwm_beeper_on(struct pwm_beeper *beeper, unsigned long period) { - unsigned long period = beeper->period; + int error; + + error = pwm_config(beeper->pwm, period / 2, period); + if (error) + return error; + + error = pwm_enable(beeper->pwm); + if (error) + return error; + + if (!beeper->amplifier_on) { + error = regulator_enable(beeper->amplifier); + if (error) { + pwm_disable(beeper->pwm); + return error; + } - if (period) { - pwm_config(beeper->pwm, period / 2, period); - pwm_enable(beeper->pwm); - } else - pwm_disable(beeper->pwm); + beeper->amplifier_on = true; + } + + return 0; +} + +static void pwm_beeper_off(struct pwm_beeper *beeper) +{ + if (beeper->amplifier_on) { + regulator_disable(beeper->amplifier); + beeper->amplifier_on = false; + } + + pwm_disable(beeper->pwm); } static void pwm_beeper_work(struct work_struct *work) { - struct pwm_beeper *beeper = - container_of(work, struct pwm_beeper, work); + struct pwm_beeper *beeper = container_of(work, struct pwm_beeper, work); + unsigned long period = READ_ONCE(beeper->period); - __pwm_beeper_set(beeper); + if (period) + pwm_beeper_on(beeper, period); + else + pwm_beeper_off(beeper); } static int pwm_beeper_event(struct input_dev *input, @@ -83,9 +113,7 @@ static int pwm_beeper_event(struct input_dev *input, static void pwm_beeper_stop(struct pwm_beeper *beeper) { cancel_work_sync(&beeper->work); - - if (beeper->period) - pwm_disable(beeper->pwm); + pwm_beeper_off(beeper); } static void pwm_beeper_close(struct input_dev *input) @@ -120,6 +148,15 @@ static int pwm_beeper_probe(struct platform_device *pdev) */ pwm_apply_args(beeper->pwm); + beeper->amplifier = devm_regulator_get(dev, "amp"); + if (IS_ERR(beeper->amplifier)) { + error = PTR_ERR(beeper->amplifier); + if (error != -EPROBE_DEFER) + dev_err(dev, "Failed to get 'amp' regulator: %d\n", + error); + return error; + } + INIT_WORK(&beeper->work, pwm_beeper_work); beeper->input = devm_input_allocate_device(dev); -- 2.20.1