From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Lechner Subject: [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator Date: Wed, 11 Jan 2017 14:02:01 -0600 Message-ID: <1484164921-30587-4-git-send-email-david@lechnology.com> References: <1484164921-30587-1-git-send-email-david@lechnology.com> Return-path: In-Reply-To: <1484164921-30587-1-git-send-email-david@lechnology.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-input@vger.kernel.org, devicetree@vger.kernel.org Cc: David Lechner , Dmitry Torokhov , Rob Herring , Mark Rutland , linux-kernel@vger.kernel.org List-Id: linux-input@vger.kernel.org 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 --- 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 +#include #include #include #include @@ -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