[PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator
From: David Lechner <david@lechnology.com>
Date: 2017-01-11 20:02:43
Also in:
linux-input, lkml
Subsystem:
input (keyboard, mouse, joystick, touchscreen) drivers, the rest · Maintainers:
Dmitry Torokhov, Linus Torvalds
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 <david@lechnology.com> --- drivers/input/misc/pwm-beeper.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-)
diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
index 30ac227..708e88e 100644
--- a/drivers/input/misc/pwm-beeper.c
+++ b/drivers/input/misc/pwm-beeper.c@@ -14,6 +14,7 @@ */ #include <linux/input.h> +#include <linux/regulator/consumer.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/of.h>
@@ -25,8 +26,10 @@ struct pwm_beeper { struct input_dev *input; struct pwm_device *pwm; + struct regulator *reg; struct work_struct work; unsigned long period; + bool reg_enabled; }; #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
@@ -38,8 +41,20 @@ static void __pwm_beeper_set(struct pwm_beeper *beeper) if (period) { pwm_config(beeper->pwm, period / 2, period); pwm_enable(beeper->pwm); - } else + if (beeper->reg) { + int error; + + error = regulator_enable(beeper->reg); + if (!error) + beeper->reg_enabled = true; + } + } else { + if (beeper->reg_enabled) { + regulator_disable(beeper->reg); + beeper->reg_enabled = false; + } pwm_disable(beeper->pwm); + } } static void pwm_beeper_work(struct work_struct *work)
@@ -82,6 +97,10 @@ static void pwm_beeper_stop(struct pwm_beeper *beeper) { cancel_work_sync(&beeper->work); + if (beeper->reg_enabled) { + regulator_disable(beeper->reg); + beeper->reg_enabled = false; + } if (beeper->period) pwm_disable(beeper->pwm); }
@@ -111,6 +130,14 @@ static int pwm_beeper_probe(struct platform_device *pdev) return error; } + beeper->reg = devm_regulator_get_optional(&pdev->dev, "amp"); + error = PTR_ERR_OR_ZERO(beeper->reg); + if (error) { + if (error != -EPROBE_DEFER) + dev_err(dev, "Failed to get amp regulator\n"); + return error; + } + /* * FIXME: pwm_apply_args() should be removed when switching to * the atomic PWM API.
--
2.7.4