tinySA/os/hal/src/pwm.c

/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file    pwm.c
 * @brief   PWM Driver code.
 *
 * @addtogroup PWM
 * @{
 */

#include "ch.h"
#include "hal.h"

#if HAL_USE_PWM || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver local definitions.                                                 */
/*===========================================================================*/

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local variables.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   PWM Driver initialization.
 * @note    This function is implicitly invoked by @p halInit(), there is
 *          no need to explicitly initialize the driver.
 *
 * @init
 */
void pwmInit(void) {

  pwm_lld_init();
}

/**
 * @brief   Initializes the standard part of a @p PWMDriver structure.
 *
 * @param[out] pwmp     pointer to a @p PWMDriver object
 *
 * @init
 */
void pwmObjectInit(PWMDriver *pwmp) {

  pwmp->state    = PWM_STOP;
  pwmp->config   = NULL;
#if defined(PWM_DRIVER_EXT_INIT_HOOK)
  PWM_DRIVER_EXT_INIT_HOOK(pwmp);
#endif
}

/**
 * @brief   Configures and activates the PWM peripheral.
 * @note    Starting a driver that is already in the @p PWM_READY state
 *          disables all the active channels.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] config    pointer to a @p PWMConfig object
 *
 * @api
 */
void pwmStart(PWMDriver *pwmp, const PWMConfig *config) {

  chDbgCheck((pwmp != NULL) && (config != NULL), "pwmStart");

  chSysLock();
  chDbgAssert((pwmp->state == PWM_STOP) || (pwmp->state == PWM_READY),
              "pwmStart(), #1", "invalid state");
  pwmp->config = config;
  pwmp->period = config->period;
  pwm_lld_start(pwmp);
  pwmp->state = PWM_READY;
  chSysUnlock();
}

/**
 * @brief   Deactivates the PWM peripheral.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 *
 * @api
 */
void pwmStop(PWMDriver *pwmp) {

  chDbgCheck(pwmp != NULL, "pwmStop");

  chSysLock();
  chDbgAssert((pwmp->state == PWM_STOP) || (pwmp->state == PWM_READY),
              "pwmStop(), #1", "invalid state");
  pwm_lld_stop(pwmp);
  pwmp->state = PWM_STOP;
  chSysUnlock();
}

/**
 * @brief   Changes the period the PWM peripheral.
 * @details This function changes the period of a PWM unit that has already
 *          been activated using @p pwmStart().
 * @pre     The PWM unit must have been activated using @p pwmStart().
 * @post    The PWM unit period is changed to the new value.
 * @note    If a period is specified that is shorter than the pulse width
 *          programmed in one of the channels then the behavior is not
 *          guaranteed.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] period    new cycle time in ticks
 *
 * @api
 */
void pwmChangePeriod(PWMDriver *pwmp, pwmcnt_t period) {

  chDbgCheck(pwmp != NULL, "pwmChangePeriod");

  chSysLock();
  chDbgAssert(pwmp->state == PWM_READY,
              "pwmChangePeriod(), #1", "invalid state");
  pwmChangePeriodI(pwmp, period);
  chSysUnlock();
}

/**
 * @brief   Enables a PWM channel.
 * @pre     The PWM unit must have been activated using @p pwmStart().
 * @post    The channel is active using the specified configuration.
 * @note    Depending on the hardware implementation this function has
 *          effect starting on the next cycle (recommended implementation)
 *          or immediately (fallback implementation).
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] channel   PWM channel identifier (0...PWM_CHANNELS-1)
 * @param[in] width     PWM pulse width as clock pulses number
 *
 * @api
 */
void pwmEnableChannel(PWMDriver *pwmp,
                      pwmchannel_t channel,
                      pwmcnt_t width) {

  chDbgCheck((pwmp != NULL) && (channel < PWM_CHANNELS),
             "pwmEnableChannel");

  chSysLock();
  chDbgAssert(pwmp->state == PWM_READY,
              "pwmEnableChannel(), #1", "not ready");
  pwm_lld_enable_channel(pwmp, channel, width);
  chSysUnlock();
}

/**
 * @brief   Disables a PWM channel.
 * @pre     The PWM unit must have been activated using @p pwmStart().
 * @post    The channel is disabled and its output line returned to the
 *          idle state.
 * @note    Depending on the hardware implementation this function has
 *          effect starting on the next cycle (recommended implementation)
 *          or immediately (fallback implementation).
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] channel   PWM channel identifier (0...PWM_CHANNELS-1)
 *
 * @api
 */
void pwmDisableChannel(PWMDriver *pwmp, pwmchannel_t channel) {

  chDbgCheck((pwmp != NULL) && (channel < PWM_CHANNELS),
             "pwmEnableChannel");

  chSysLock();
  chDbgAssert(pwmp->state == PWM_READY,
              "pwmDisableChannel(), #1", "not ready");
  pwm_lld_disable_channel(pwmp, channel);
  chSysUnlock();
}

#endif /* HAL_USE_PWM */

/** @} */