android-things: Prep for peripheralmanager support

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

include/peripheralmanager/pwm.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SYSTEM_PERIPHERALMANAGER_PWM_H_
+#define SYSTEM_PERIPHERALMANAGER_PWM_H_
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+__BEGIN_DECLS
+
+/// @defgroup Pwm Pwm Interface
+/// @brief Functions to control PWM pins.
+///
+/// These functions can be used to control PWM.
+/// @{
+
+typedef struct BPwm BPwm;
+
+/// Sets the PWM duty cycle.
+/// @param gpio Pointer to the BPwm struct
+/// @param duty_cycle Double between 0 and 100 inclusive.
+/// @return 0 on success, errno on error.
+int BPwm_setDutyCycle(const BPwm* pwm, double duty_cycle);
+
+/// Sets the PWM frequency.
+/// @param gpio Pointer to the BPwm struct
+/// @param freq Double denoting the frequency in Hz.
+/// @return 0 on success, errno on error.
+int BPwm_setFrequencyHz(const BPwm* pwm, double frequency);
+
+/// Enables the PWM.
+/// @param gpio Pointer to the BPwm struct
+/// @return 0 on success, errno on error.
+int BPwm_enable(const BPwm* pwm);
+
+/// Disables the PWM.
+/// @param gpio Pointer to the BPwm struct
+/// @return 0 on success, errno on error.
+int BPwm_disable(const BPwm* pwm);
+
+/// Destroys a BPwm struct.
+/// @param pwm Pointer to the BPwm struct.
+void BPwm_delete(BPwm* pwm);
+
+/// @}
+
+__END_DECLS
+
+#endif  // SYSTEM_PERIPHERALMANAGER_PWM_H_