tinySA/os/hal/platforms/AT91SAM7/pwm_lld.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/>.

                                      ---

    A special exception to the GPL can be applied should you wish to distribute
    a combined work that includes ChibiOS/RT, without being obliged to provide
    the source code for any proprietary components. See the file exception.txt
    for full details of how and when the exception can be applied.
*/
/*
   This file has been contributed by:
		Andrew Hannam aka inmarket.
*/

/**
 * @file    AT91SAM7/pwm_lld.c
 * @brief   AT91SAM7 PWM Driver subsystem low level driver source.
 *
 * @addtogroup PWM
 * @{
 */

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

#if HAL_USE_PWM || defined(__DOXYGEN__)

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

#ifdef UNUSED 
#elif defined(__GNUC__) 
# define UNUSED(x) UNUSED_ ## x __attribute__((unused)) 
#elif defined(__LCLINT__) 
# define UNUSED(x) /*@unused@*/ x 
#else 
# define UNUSED(x) x 
#endif 

#define PWMC_M	((AT91S_PWMC *)AT91C_PWMC_MR)

#define PWM_MCK_MASK					0x0F00
#define PWM_MCK_SHIFT					8

typedef struct pindef {
	uint32_t	portpin;	/* Set to 0 if this pin combination is invalid */
	AT91S_PIO	*pio;
	AT91_REG	*perab;
} pindef_t;

typedef struct pwmpindefs {
	pindef_t	pin[3];
} pwmpindefs_t;

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

#if PWM_USE_PWM1 && !defined(__DOXYGEN__)
PWMDriver PWMD1;
#endif

#if PWM_USE_PWM2 && !defined(__DOXYGEN__)
PWMDriver PWMD2;
#endif

#if PWM_USE_PWM3 && !defined(__DOXYGEN__)
PWMDriver PWMD3;
#endif

#if PWM_USE_PWM4 && !defined(__DOXYGEN__)
PWMDriver PWMD4;
#endif

/*===========================================================================*/
/* Driver local variables and types.                                         */
/*===========================================================================*/

#if (SAM7_PLATFORM == SAM7S64) || (SAM7_PLATFORM == SAM7S128) ||            \
    (SAM7_PLATFORM == SAM7S256) || (SAM7_PLATFORM == SAM7S512)

#if PWM_USE_PWM1 && !defined(__DOXYGEN__)
static const pwmpindefs_t PWMP1 = {{
		{ AT91C_PA0_PWM0 , AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_ASR },
		{ AT91C_PA11_PWM0, AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_BSR },
		{ AT91C_PA23_PWM0, AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_BSR },
	}};
#endif
#if PWM_USE_PWM2 && !defined(__DOXYGEN__)
static const pwmpindefs_t PWMP2 = {{
		{ AT91C_PA1_PWM1 , AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_ASR },
		{ AT91C_PA12_PWM1, AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_BSR },
		{ AT91C_PA24_PWM1, AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_BSR },
	}};
#endif
#if PWM_USE_PWM3 && !defined(__DOXYGEN__)
static const pwmpindefs_t PWMP3 = {{
		{ AT91C_PA2_PWM2 , AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_ASR },
		{ AT91C_PA13_PWM2, AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_BSR },
		{ AT91C_PA25_PWM2, AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_BSR },
	}};
#endif
#if PWM_USE_PWM4 && !defined(__DOXYGEN__)
static const pwmpindefs_t PWMP4 = {{
		{ AT91C_PA7_PWM3 , AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_BSR },
		{ AT91C_PA14_PWM3, AT91C_BASE_PIOA, &AT91C_BASE_PIOA->PIO_BSR },
		{ 0, 0, 0 },
	}};
#endif

#elif (SAM7_PLATFORM == SAM7X128) || (SAM7_PLATFORM == SAM7X256) ||         \
      (SAM7_PLATFORM == SAM7X512)

#if PWM_USE_PWM1 && !defined(__DOXYGEN__)
static const pwmpindefs_t PWMP1 = {{
		{ AT91C_PB19_PWM0, AT91C_BASE_PIOB, &AT91C_BASE_PIOB->PIO_ASR },
		{ AT91C_PB27_PWM0, AT91C_BASE_PIOB, &AT91C_BASE_PIOB->PIO_BSR },
		{ 0, 0, 0 },
	}};
#endif
#if PWM_USE_PWM2 && !defined(__DOXYGEN__)
static const pwmpindefs_t PWMP2 = {{
		{ AT91C_PB20_PWM1, AT91C_BASE_PIOB, &AT91C_BASE_PIOB->PIO_ASR },
		{ AT91C_PB28_PWM1, AT91C_BASE_PIOB, &AT91C_BASE_PIOB->PIO_BSR },
		{ 0, 0, 0 },
	}};
#endif
#if PWM_USE_PWM3 && !defined(__DOXYGEN__)
static const pwmpindefs_t PWMP3 = {{
		{ AT91C_PB21_PWM2, AT91C_BASE_PIOB, &AT91C_BASE_PIOB->PIO_ASR },
		{ AT91C_PB29_PWM2, AT91C_BASE_PIOB, &AT91C_BASE_PIOB->PIO_BSR },
		{ 0, 0, 0 },
	}};
#endif
#if PWM_USE_PWM4 && !defined(__DOXYGEN__)
static const pwmpindefs_t PWMP4 = {{
		{ AT91C_PB22_PWM3, AT91C_BASE_PIOB, &AT91C_BASE_PIOB->PIO_ASR },
		{ AT91C_PB30_PWM3, AT91C_BASE_PIOB, &AT91C_BASE_PIOB->PIO_BSR },
		{ 0, 0, 0 },
	}};
#endif

#else
	#error "PWM pins not defined for this SAM7 version"
#endif

#if PWM_USE_PWM2 && !defined(__DOXYGEN__)
PWMDriver PWMD2;
#endif

#if PWM_USE_PWM3 && !defined(__DOXYGEN__)
PWMDriver PWMD3;
#endif

#if PWM_USE_PWM4 && !defined(__DOXYGEN__)
PWMDriver PWMD4;
#endif

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

/*===========================================================================*/
/* Driver interrupt handlers.                                                */
/*===========================================================================*/

#if defined(__GNUC__)
__attribute__((noinline))
#endif
/**
 * @brief   Common IRQ handler.
 */
static void pwm_lld_serve_interrupt(void) {
	uint32_t	isr;
	
	isr = PWMC_M->PWMC_ISR;
#if PWM_USE_PWM1
	if ((isr & 1) && PWMD1.config->channels[0].callback)
		PWMD1.config->channels[0].callback(&PWMD1);
#endif
#if PWM_USE_PWM2
	if ((isr & 2) && PWMD2.config->channels[0].callback)
		PWMD2.config->channels[0].callback(&PWMD2);
#endif
#if PWM_USE_PWM3
	if ((isr & 4) && PWMD3.config->channels[0].callback)
		PWMD3.config->channels[0].callback(&PWMD3);
#endif
#if PWM_USE_PWM4
	if ((isr & 8) && PWMD4.config->channels[0].callback)
		PWMD4.config->channels[0].callback(&PWMD4);
#endif
}

CH_IRQ_HANDLER(PWMIrqHandler) {
  CH_IRQ_PROLOGUE();
  pwm_lld_serve_interrupt();
  AT91C_BASE_AIC->AIC_EOICR = 0;
  CH_IRQ_EPILOGUE();
}

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

/**
 * @brief   Low level PWM driver initialization.
 *
 * @notapi
 */
void pwm_lld_init(void) {

	/* Driver initialization.*/
#if PWM_USE_PWM1 && !defined(__DOXYGEN__)
	pwmObjectInit(&PWMD1);
	PWMD1.chbit = 1;
	PWMD1.reg = AT91C_BASE_PWMC_CH0;
	PWMD1.pins = &PWMP1;
#endif

#if PWM_USE_PWM2 && !defined(__DOXYGEN__)
	pwmObjectInit(&PWMD2);
	PWMD2.chbit = 2;
	PWMD2.reg = AT91C_BASE_PWMC_CH1;
	PWMD2.pins = &PWMP2;
#endif

#if PWM_USE_PWM3 && !defined(__DOXYGEN__)
	pwmObjectInit(&PWMD3);
	PWMD3.chbit = 4;
	PWMD3.reg = AT91C_BASE_PWMC_CH2;
	PWMD3.pins = &PWMP3;
#endif

#if PWM_USE_PWM4 && !defined(__DOXYGEN__)
	pwmObjectInit(&PWMD4);
	PWMD4.chbit = 8;
	PWMD4.reg = AT91C_BASE_PWMC_CH3;
	PWMD4.pins = &PWMP4;
#endif

	/* Turn on PWM in the power management controller */
	AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_PWMC);
  
	/* Setup interrupt handler */
	PWMC_M->PWMC_IDR = 0xFFFFFFFF;
	AIC_ConfigureIT(AT91C_ID_PWMC,
		  AT91C_AIC_SRCTYPE_HIGH_LEVEL | AT91SAM7_PWM_PRIORITY,
		  PWMIrqHandler);
    AIC_EnableIT(AT91C_ID_PWMC);
}

/**
 * @brief   Configures and activates the PWM peripheral.
 *
 * @param[in] pwmp      pointer to the @p PWMDriver object
 *
 * @notapi
 */
void pwm_lld_start(PWMDriver *pwmp) {
	uint32_t	mode, mr, div, pre;

	/* Steps:
		1. Turn the IO pin to a PWM output
		2. Configuration of Clock if DIVA or DIVB used
		3. Selection of the clock for each channel (CPRE field in the PWM_CMRx register)
		4. Configuration of the waveform alignment for each channel (CALG field in the PWM_CMRx register)
		5. Configuration of the output waveform polarity for each channel (CPOL in the PWM_CMRx register)
		6. Configuration of the period for each channel (CPRD in the PWM_CPRDx register). Writing in
			PWM_CPRDx Register is possible while the channel is disabled. After validation of the
			channel, the user must use PWM_CUPDx Register to update PWM_CPRDx
		7. Enable Interrupts (Writing CHIDx in the PWM_IER register)
	*/

	/* Make sure it is off first */
	pwm_lld_disable_channel(pwmp, 0);

	/* Configuration.*/
	mode = pwmp->config->channels[0].mode;

	/* Step 1 */
	if (mode & PWM_OUTPUT_PIN1) {
		pwmp->pins->pin[0].perab[0]		= pwmp->pins->pin[0].portpin;		/* Select A or B peripheral */
		pwmp->pins->pin[0].pio->PIO_PDR	= pwmp->pins->pin[0].portpin;		/* Turn PIO into PWM output */
		pwmp->pins->pin[0].pio->PIO_MDDR	= pwmp->pins->pin[0].portpin;		/* Turn off PIO multi-drive */
		if (mode & PWM_DISABLEPULLUP_PIN1)
			pwmp->pins->pin[0].pio->PIO_PPUDR	= pwmp->pins->pin[0].portpin;	/* Turn off PIO pullup */
		else
			pwmp->pins->pin[0].pio->PIO_PPUER	= pwmp->pins->pin[0].portpin;	/* Turn on PIO pullup */
	}
	if (mode & PWM_OUTPUT_PIN2) {
		pwmp->pins->pin[1].perab[0]		= pwmp->pins->pin[1].portpin;
		pwmp->pins->pin[1].pio->PIO_PDR	= pwmp->pins->pin[1].portpin;
		pwmp->pins->pin[1].pio->PIO_MDDR	= pwmp->pins->pin[1].portpin;
		if (mode & PWM_DISABLEPULLUP_PIN2)
			pwmp->pins->pin[1].pio->PIO_PPUDR	= pwmp->pins->pin[1].portpin;
		else
			pwmp->pins->pin[1].pio->PIO_PPUER	= pwmp->pins->pin[1].portpin;
	}
	if ((mode & PWM_OUTPUT_PIN3) && pwmp->pins->pin[2].portpin) {
		pwmp->pins->pin[2].perab[0]		= pwmp->pins->pin[2].portpin;
		pwmp->pins->pin[2].pio->PIO_PDR	= pwmp->pins->pin[2].portpin;
		pwmp->pins->pin[2].pio->PIO_MDDR	= pwmp->pins->pin[2].portpin;
		if (mode & PWM_DISABLEPULLUP_PIN3)
			pwmp->pins->pin[2].pio->PIO_PPUDR	= pwmp->pins->pin[2].portpin;
		else
			pwmp->pins->pin[2].pio->PIO_PPUER	= pwmp->pins->pin[2].portpin;
	}

	/* Step 2 */
	if ((mode & PWM_MCK_MASK) == PWM_MCK_DIV_CLKA) {
		if (!pwmp->config->frequency) {
			/* As slow as we go */
			PWMC_M->PWMC_MR = (PWMC_M->PWMC_MR & 0xFFFF0000) | (10 << 8) | (255 << 0);
		} else if (pwmp->config->frequency > MCK) {
			/* Just use MCLK */
			mode &= ~PWM_MCK_MASK;
		} else {
			div = MCK / pwmp->config->frequency;
			if (mode & PWM_OUTPUT_CENTER) div >>= 1;
			for(pre = 0; div > 255 && pre < 10; pre++) div >>= 1;
			if (div > 255) div = 255;
			PWMC_M->PWMC_MR = (PWMC_M->PWMC_MR & 0xFFFF0000) | (pre << 8) | (div << 0);
		}
	} else if ((mode & PWM_MCK_MASK) == PWM_MCK_DIV_CLKB) {
		if (!pwmp->config->frequency) {
			/* As slow as we go */
			PWMC_M->PWMC_MR = (PWMC_M->PWMC_MR & 0x0000FFFF) | (10 << 24) | (255 << 16);
		} else if (pwmp->config->frequency > MCK) {
			/* Just use MCLK */
			mode &= ~PWM_MCK_MASK;
		} else {
			div = MCK / pwmp->config->frequency;
			if (mode & PWM_OUTPUT_CENTER) div >>= 1;
			for(pre = 0; div > 255 && pre < 10; pre++) div >>= 1;
			if (div > 255) div = 255;
			PWMC_M->PWMC_MR = (PWMC_M->PWMC_MR & 0x0000FFFF) | (pre << 24) | (div << 16);
		}
	}

	/* Step 3 -> 5 */
	mr = (mode & PWM_MCK_MASK) >> PWM_MCK_SHIFT;
	if (mode & PWM_OUTPUT_CENTER) mr |= AT91C_PWMC_CALG;
	if (mode & PWM_OUTPUT_ACTIVE_HIGH) mr |= AT91C_PWMC_CPOL;
	pwmp->reg->PWMC_CMR = mr;

	/* Step 6 */
	pwmp->reg->PWMC_CPRDR = pwmp->period;
	
	/* Step 7 */
	if (pwmp->config->channels[0].callback)
		PWMC_M->PWMC_IER = pwmp->chbit;
}

/**
 * @brief   Deactivates the PWM peripheral.
 *
 * @param[in] pwmp      pointer to the @p PWMDriver object
 *
 * @notapi
 */
void pwm_lld_stop(PWMDriver *pwmp) {
	/* Make sure it is off */
	pwm_lld_disable_channel(pwmp, 0);
	
	/* Turn the pin back to a PIO pin - we have forgotten pull-up and multi-drive state for the pin though */
	if (pwmp->config->channels[0].mode & PWM_OUTPUT_PIN1)
		pwmp->pins->pin[0].pio->PIO_PER	= pwmp->pins->pin[0].portpin;
	if (pwmp->config->channels[0].mode & PWM_OUTPUT_PIN2)
		pwmp->pins->pin[1].pio->PIO_PER	= pwmp->pins->pin[1].portpin;
	if ((pwmp->config->channels[0].mode & PWM_OUTPUT_PIN3) && pwmp->pins->pin[2].portpin)
		pwmp->pins->pin[2].pio->PIO_PER	= pwmp->pins->pin[2].portpin;
}

/**
 * @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    The function has effect at the next cycle start.
 * @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
 *
 * @notapi
 */
void pwm_lld_change_period(PWMDriver *pwmp, pwmcnt_t period) {
	pwmp->period = period;
	
	if (PWMC_M->PWMC_SR & pwmp->chbit) {
		pwmp->reg->PWMC_CMR |= AT91C_PWMC_CPD;
		pwmp->reg->PWMC_CUPDR = period;
	} else {
		pwmp->reg->PWMC_CPRDR = period;
	}
}

/**
 * @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
 *
 * @notapi
 */
void pwm_lld_enable_channel(PWMDriver *pwmp,
                            pwmchannel_t UNUSED(channel),
                            pwmcnt_t width) {
	/*
		6. Configuration of the duty cycle for each channel (CDTY in the PWM_CDTYx register).
			Writing in PWM_CDTYx Register is possible while the channel is disabled. After validation of
			the channel, the user must use PWM_CUPDx Register to update PWM_CDTYx.
		7. Enable the PWM channel (Writing CHIDx in the PWM_ENA register)
	*/

	/* Step 6 */
	if (PWMC_M->PWMC_SR & pwmp->chbit) {
		pwmp->reg->PWMC_CMR &= ~AT91C_PWMC_CPD;
		pwmp->reg->PWMC_CUPDR = width;
	} else {
		pwmp->reg->PWMC_CDTYR = width;
		PWMC_M->PWMC_ENA = pwmp->chbit;
	}
	
	/* Step 7 */
	PWMC_M->PWMC_ENA = pwmp->chbit;
}

/**
 * @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)
 *
 * @notapi
 */
void pwm_lld_disable_channel(PWMDriver *pwmp, pwmchannel_t UNUSED(channel)) {
	PWMC_M->PWMC_IDR = pwmp->chbit;
	PWMC_M->PWMC_DIS = pwmp->chbit;
}

#endif /* HAL_USE_PWM */

/** @} */