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/****************************************************************************
*
* Copyright (C) 2012 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file PWM servo driver.
*
* The pwm_servo driver supports servos connected to STM32 timer
* blocks.
*
* Servo values can be set either with the PWM_SERVO_SET ioctl, or
* by writing an array of servo_position_t values to the device.
* Writing a value of 0 to a channel suppresses any output for that
* channel.
*
* Servo values can be read back either with the PWM_SERVO_GET
* ioctl, or by reading an array of servo_position_t values
* from the device.
*
* Attempts to set a channel that is not configured are ignored,
* and unconfigured channels always read zero.
*
* The PWM_SERVO_ARM / PWM_SERVO_DISARM calls globally arm
* (enable) and disarm (disable) all servo outputs.
*/
#include <sys/ioctl.h>
#define _PWM_SERVO_BASE 0x7500
#define PWM_SERVO_ARM _IOC(_PWM_SERVO_BASE, 0)
#define PWM_SERVO_DISARM _IOC(_PWM_SERVO_BASE, 1)
#define PWM_SERVO_SET(_servo) _IOC(_PWM_SERVO_BASE, 0x20 + _servo)
#define PWM_SERVO_GET(_servo) _IOC(_PWM_SERVO_BASE, 0x40 + _servo)
typedef uint16_t servo_position_t;
/* configuration limits */
#define PWM_SERVO_MAX_TIMERS 3
#define PWM_SERVO_MAX_CHANNELS 8
struct pwm_servo_config {
/* rate (in Hz) of PWM updates */
uint32_t update_rate;
/* array of timers dedicated to PWM servo use */
struct pwm_servo_timer {
uint32_t base;
uint32_t clock_register;
uint32_t clock_bit;
uint32_t clock_freq;
} timers[PWM_SERVO_MAX_TIMERS];
/* array of channels in logical order */
struct pwm_servo_channel {
uint32_t gpio;
uint8_t timer_index;
uint8_t timer_channel;
servo_position_t default_value;
} channels[PWM_SERVO_MAX_CHANNELS];
};
extern int pwm_servo_init(const struct pwm_servo_config *config);
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