ChibiOS/os/hal/platforms/LPC8xx/gpt_lld.c

283 lines
7.1 KiB
C

/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012,2013 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 LPC8xx/gpt_lld.c
* @brief LPC8xx GPT subsystem low level driver source.
*
* @addtogroup GPT
* @{
*/
#include "ch.h"
#include "hal.h"
#if HAL_USE_GPT || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
/**
* @brief GPT1 driver identifier.
* @note The driver GPT1 allocates MRT channel0 when enabled.
*/
#if LPC8xx_GPT_USE_MRT0 || defined(__DOXYGEN__)
GPTDriver GPTD1;
#endif
/**
* @brief GPT2 driver identifier.
* @note The driver GPT1 allocates MRT channel1 when enabled.
*/
#if LPC8xx_GPT_USE_MRT1 || defined(__DOXYGEN__)
GPTDriver GPTD2;
#endif
/**
* @brief GPT3 driver identifier.
* @note The driver GPT1 allocates MRT channel2 when enabled.
*/
#if LPC8xx_GPT_USE_MRT2 || defined(__DOXYGEN__)
GPTDriver GPTD3;
#endif
/**
* @brief GPT4 driver identifier.
* @note The driver GPT1 allocates MRT channel3 when enabled.
*/
#if LPC8xx_GPT_USE_MRT3 || defined(__DOXYGEN__)
GPTDriver GPTD4;
#endif
/*===========================================================================*/
/* Driver local variables. */
/*===========================================================================*/
static uint32_t clk_enabled;
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/**
* @brief Shared IRQ handler.
*
* @param[in] gptp pointer to a @p GPTDriver object
* @param[in] irq_flag irq flag bit
*/
static void gpt_lld_serve_interrupt( GPTDriver *gptp ) {
if (gptp->tmr->STAT & 0x01) {
gptp->tmr->STAT |= 0x01;
if (gptp->state == GPT_ONESHOT) {
gptp->state = GPT_READY; /* Back in GPT_READY state. */
}
gptp->config->callback(gptp);
}
return;
}
/*===========================================================================*/
/* Driver interrupt handlers. */
/*===========================================================================*/
/**
* @brief MRT IRQ handler.
*
*/
CH_IRQ_HANDLER(Vector68) {
CH_IRQ_PROLOGUE();
#if LPC8xx_GPT_USE_MRT0
gpt_lld_serve_interrupt( &GPTD1 );
#endif
#if LPC8xx_GPT_USE_MRT1
gpt_lld_serve_interrupt( &GPTD2 );
#endif
#if LPC8xx_GPT_USE_MRT2
gpt_lld_serve_interrupt( &GPTD3 );
#endif
#if LPC8xx_GPT_USE_MRT3
gpt_lld_serve_interrupt( &GPTD4 );
#endif
CH_IRQ_EPILOGUE();
}
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Low level GPT driver initialization.
*
* @notapi
*/
void gpt_lld_init(void) {
#if LPC8xx_GPT_USE_MRT0
GPTD1.tmr = &(LPC_MRT->Channel[0]);
gptObjectInit(&GPTD1);
GPTD1.mask = (1<<0);
#endif
#if LPC8xx_GPT_USE_MRT1
GPTD2.tmr = &(LPC_MRT->Channel[1]);
gptObjectInit(&GPTD2);
GPTD1.mask = (1<<1);
#endif
#if LPC8xx_GPT_USE_MRT2
GPTD3.tmr = &(LPC_MRT->Channel[2]);
gptObjectInit(&GPTD3);
GPTD1.mask = (1<<2);
#endif
#if LPC8xx_GPT_USE_MRT3
GPTD4.tmr = &(LPC_MRT->Channel[3]);
gptObjectInit(&GPTD4);
GPTD1.mask = (1<<3);
#endif
clk_enabled = FALSE;
return;
}
/**
* @brief Configures and activates a GPT channel.
*
* @param[in] gptp pointer to the @p GPTDriver object
*
* @notapi
*/
void gpt_lld_start(GPTDriver *gptp) {
if( !clk_enabled ) {
/* Enable clock & reset MRT */
LPC_SYSCON->SYSAHBCLKCTRL |= (1<<10);
LPC_SYSCON->PRESETCTRL &= ~(1<<7);
LPC_SYSCON->PRESETCTRL |= (1<<7);
nvicEnableVector(MRT_IRQn,
CORTEX_PRIORITY_MASK(LPC8xx_GPT_MRT_IRQ_PRIORITY));
clk_enabled |= gptp->mask;
}
/* Prescaler value calculation.*/
gptp->pr = (LPC8xx_SYSCLK / gptp->config->frequency);
chDbgAssert((gptp->pr * gptp->config->frequency) == LPC8xx_SYSCLK,
"gpt_lld_start(), #1", "invalid frequency");
/* MRT Channel configuration.*/
gptp->tmr->CTRL = 0;
gptp->tmr->STAT |= 1;
}
/**
* @brief Deactivates a GPT channel.
*
* @param[in] gptp pointer to the @p GPTDriver object
*
* @notapi
*/
void gpt_lld_stop(GPTDriver *gptp) {
/* Shared peripheral -
mark this channel as disabled */
clk_enabled &= ~gptp->mask;
/* All channels disabled? */
if( !clk_enabled )
{
/* Disable periheral */
nvicDisableVector(MRT_IRQn);
LPC_SYSCON->SYSAHBCLKCTRL &= ~(1<<10);
}
return;
}
/**
* @brief Starts the timer in continuous/One shot mode.
*
* @param[in] gptp pointer to the @p GPTDriver object
* @param[in] interval period in ticks
*
* @notapi
*/
void gpt_lld_start_timer(GPTDriver *gptp, gptcnt_t interval) {
gptp->tmr->INTVAL = (1<<31)|((interval*gptp->pr) - 1);
if (gptp->state == GPT_ONESHOT)
gptp->tmr->CTRL = (1<<1)|1;
else
gptp->tmr->CTRL = 1;
}
/**
* @brief Stops the timer.
*
* @param[in] gptp pointer to the @p GPTDriver object
*
* @notapi
*/
void gpt_lld_stop_timer(GPTDriver *gptp) {
gptp->tmr->INTVAL = (1<<31);
gptp->tmr->CTRL = 0;
gptp->tmr->STAT |= 1;
}
/**
* @brief Starts the timer in one shot mode and waits for completion.
* @details This function specifically polls the timer waiting for completion
* in order to not have extra delays caused by interrupt servicing,
* this function is only recommended for short delays.
*
* @param[in] gptp pointer to the @p GPTDriver object
* @param[in] interval time interval in ticks
*
* @notapi
*/
void gpt_lld_polled_delay(GPTDriver *gptp, gptcnt_t interval) {
gptp->tmr->INTVAL = (1<<31)|((interval*gptp->pr) - 1);
gptp->tmr->CTRL = (1<<1);
while (gptp->tmr->STAT & (1<<1))
;
gptp->tmr->CTRL = 0;
gptp->tmr->STAT |= 1;
}
#endif /* HAL_USE_GPT */
/** @} */