/***************************************************************************
 *   Copyright (C) 01/2008 by Olaf Rempel                                  *
 *   razzor@kopf-tisch.de                                                  *
 *                                                                         *
 *   This program 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; version 2 of the License                *
 *                                                                         *
 *   This program 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, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <stdint.h>
#include <stdio.h>

#include "AT91SAM7S256.h"
#include "board.h"
#include "at91_pitc.h"

static uint16_t adc_result[4];

static void at91_adc_isr(void)
{
	AT91S_PDC *pdc = AT91C_BASE_PDC_ADC;
	pdc->PDC_RPR = (uint32_t) &adc_result;
	pdc->PDC_RCR = ARRAY_SIZE(adc_result);
	pdc->PDC_PTCR = AT91C_PDC_RXTEN;

	/* clear interrupts */
	AT91S_ADC *adc = AT91C_BASE_ADC;
	uint32_t status = adc->ADC_SR;
	status = status;
}

static uint32_t adc_trigger(struct pitc_timer *timer)
{
	*AT91C_ADC_CR = AT91C_ADC_START;
	return PITC_RESTART_TIMER;
}

static struct pitc_timer adc_timer = {
	.interval = 100,
	.func = &adc_trigger,
};

void at91_adc_test_init(void)
{
	/* enable ADC clock */
	*AT91C_PMC_PCER = (1 << AT91C_ID_ADC);

	/* ADC Software reset */
	AT91S_ADC *adc = AT91C_BASE_ADC;
	adc->ADC_CR = AT91C_ADC_SWRST;

	/*
	 * ADC config: 10bit, no sleep
	 * 4.8MHz (48MHz / ((4 +1) * 2) = 4.8MHz)
	 * 96 cycles Startup ((11 +1) * 8 / 4.8MHz = 20us)
	 * 3 cycles SH ((2 +1) / 4.8MHz = 625ns)
	 * Conversion time per channel @5MHz ~2us
	 */
	adc->ADC_MR = AT91C_ADC_TRGEN_DIS |
			AT91C_ADC_LOWRES_10_BIT |
			AT91C_ADC_SLEEP_NORMAL_MODE |
			(AT91C_ADC_PRESCAL & (4 << 8)) |
			(AT91C_ADC_STARTUP & (11 << 16)) |
			(AT91C_ADC_SHTIM & (2 << 24));

	/* setup PDC */
	AT91S_PDC *pdc = AT91C_BASE_PDC_ADC;
	pdc->PDC_RPR = (uint32_t) &adc_result;
	pdc->PDC_RCR = ARRAY_SIZE(adc_result);
	pdc->PDC_PTCR = AT91C_PDC_RXTEN;

	/* enable 4 channels, PDC Interrupt */
	adc->ADC_CHER = 0xF0;
	adc->ADC_IER = AT91C_ADC_ENDRX;

	/* low priority, level triggered, own vector */
	AT91S_AIC *aic = AT91C_BASE_AIC;
	aic->AIC_SMR[AT91C_ID_ADC] = IRQPRIO_ADC | AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL;
	aic->AIC_SVR[AT91C_ID_ADC] = (uint32_t)at91_adc_isr;
	aic->AIC_IECR = (1<<AT91C_ID_ADC);

	pitc_schedule_timer(&adc_timer);
}