px4-firmware/apps/drivers/stm32/adc/adc.cpp

388 lines
8.9 KiB
C++

/****************************************************************************
*
* 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 adc.cpp
*
* Driver for the STM32 ADC.
*
* This is a low-rate driver, designed for sampling things like voltages
* and so forth. It avoids the gross complexity of the NuttX ADC driver.
*/
#include <nuttx/config.h>
#include <drivers/device/device.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <arch/board/board.h>
#include <drivers/drv_hrt.h>
#include <drivers/drv_adc.h>
#include <arch/stm32/chip.h>
#include <stm32_internal.h>
#include <stm32_gpio.h>
#include <systemlib/err.h>
#include <systemlib/perf_counter.h>
/*
* Register accessors.
* For now, no reason not to just use ADC1.
*/
#define REG(_reg) (*(volatile uint32_t *)(STM32_ADC1_BASE + _reg))
#define rSR REG(STM32_ADC_SR_OFFSET)
#define rCR1 REG(STM32_ADC_CR1_OFFSET)
#define rCR2 REG(STM32_ADC_CR2_OFFSET)
#define rSMPR1 REG(STM32_ADC_SMPR1_OFFSET)
#define rSMPR2 REG(STM32_ADC_SMPR2_OFFSET)
#define rJOFR1 REG(STM32_ADC_JOFR1_OFFSET)
#define rJOFR2 REG(STM32_ADC_JOFR2_OFFSET)
#define rJOFR3 REG(STM32_ADC_JOFR3_OFFSET)
#define rJOFR4 REG(STM32_ADC_JOFR4_OFFSET)
#define rHTR REG(STM32_ADC_HTR_OFFSET)
#define rLTR REG(STM32_ADC_LTR_OFFSET)
#define rSQR1 REG(STM32_ADC_SQR1_OFFSET)
#define rSQR2 REG(STM32_ADC_SQR2_OFFSET)
#define rSQR3 REG(STM32_ADC_SQR3_OFFSET)
#define rJSQR REG(STM32_ADC_JSQR_OFFSET)
#define rJDR1 REG(STM32_ADC_JDR1_OFFSET)
#define rJDR2 REG(STM32_ADC_JDR2_OFFSET)
#define rJDR3 REG(STM32_ADC_JDR3_OFFSET)
#define rJDR4 REG(STM32_ADC_JDR4_OFFSET)
#define rDR REG(STM32_ADC_DR_OFFSET)
#ifdef STM32_ADC_CCR
# define rCCR REG(STM32_ADC_CCR_OFFSET)
#endif
class ADC : public device::CDev
{
public:
ADC(uint32_t channels);
~ADC();
virtual int init();
virtual int ioctl(file *filp, int cmd, unsigned long arg);
virtual ssize_t read(file *filp, char *buffer, size_t len);
protected:
virtual int open_first(struct file *filp);
virtual int close_last(struct file *filp);
private:
static const hrt_abstime _tickrate = 10000; /**< 100Hz base rate */
hrt_call _call;
perf_counter_t _sample_perf;
unsigned _channel_count;
adc_msg_s *_samples; /**< sample buffer */
/** work trampoline */
static void _tick_trampoline(void *arg);
/** worker function */
void _tick();
/**
* Sample a single channel and return the measured value.
*
* @param channel The channel to sample.
* @return The sampled value, or 0xffff if
* sampling failed.
*/
uint16_t _sample(unsigned channel);
};
ADC::ADC(uint32_t channels) :
CDev("adc", ADC_DEVICE_PATH),
_sample_perf(perf_alloc(PC_ELAPSED, "ADC samples")),
_channel_count(0),
_samples(nullptr)
{
_debug_enabled = true;
/* always enable the temperature sensor */
channels |= 1 << 16;
/* allocate the sample array */
for (unsigned i = 0; i < 32; i++) {
if (channels & (1 << i)) {
_channel_count++;
}
}
_samples = new adc_msg_s[_channel_count];
/* prefill the channel numbers in the sample array */
if (_samples != nullptr) {
unsigned index = 0;
for (unsigned i = 0; i < 32; i++) {
if (channels & (1 << i)) {
_samples[index].am_channel = i;
_samples[index].am_data = 0;
index++;
}
}
}
}
ADC::~ADC()
{
if (_samples != nullptr)
delete _samples;
}
int
ADC::init()
{
/* do calibration if supported */
#ifdef ADC_CR2_CAL
rCR2 |= ADC_CR2_CAL;
usleep(100);
if (rCR2 & ADC_CR2_CAL)
return -1;
#endif
/* arbitrarily configure all channels for 55 cycle sample time */
rSMPR1 = 0b00000011011011011011011011011011;
rSMPR2 = 0b00011011011011011011011011011011;
/* XXX for F2/4, might want to select 12-bit mode? */
rCR1 = 0;
/* enable the temperature sensor / Vrefint channel if supported*/
rCR2 =
#ifdef ADC_CR2_TSVREFE
/* enable the temperature sensor in CR2 */
ADC_CR2_TSVREFE |
#endif
0;
#ifdef ADC_CCR_TSVREFE
/* enable temperature sensor in CCR */
rCCR = ADC_CCR_TSVREFE;
#endif
/* configure for a single-channel sequence */
rSQR1 = 0;
rSQR2 = 0;
rSQR3 = 0; /* will be updated with the channel each tick */
/* power-cycle the ADC and turn it on */
rCR2 &= ~ADC_CR2_ADON;
usleep(10);
rCR2 |= ADC_CR2_ADON;
usleep(10);
rCR2 |= ADC_CR2_ADON;
usleep(10);
/* kick off a sample and wait for it to complete */
hrt_abstime now = hrt_absolute_time();
rCR2 |= ADC_CR2_SWSTART;
while (!(rSR & ADC_SR_EOC)) {
/* don't wait for more than 500us, since that means something broke - should reset here if we see this */
if ((hrt_absolute_time() - now) > 500) {
log("sample timeout");
return -1;
return 0xffff;
}
}
debug("init done");
/* create the device node */
return CDev::init();
}
int
ADC::ioctl(file *filp, int cmd, unsigned long arg)
{
return -ENOTTY;
}
ssize_t
ADC::read(file *filp, char *buffer, size_t len)
{
const size_t maxsize = sizeof(adc_msg_s) * _channel_count;
if (len > maxsize)
len = maxsize;
/* block interrupts while copying samples to avoid racing with an update */
irqstate_t flags = irqsave();
memcpy(buffer, _samples, len);
irqrestore(flags);
return len;
}
int
ADC::open_first(struct file *filp)
{
/* get fresh data */
_tick();
/* and schedule regular updates */
hrt_call_every(&_call, _tickrate, _tickrate, _tick_trampoline, this);
return 0;
}
int
ADC::close_last(struct file *filp)
{
hrt_cancel(&_call);
return 0;
}
void
ADC::_tick_trampoline(void *arg)
{
((ADC *)arg)->_tick();
}
void
ADC::_tick()
{
/* scan the channel set and sample each */
for (unsigned i = 0; i < _channel_count; i++)
_samples[i].am_data = _sample(_samples[i].am_channel);
}
uint16_t
ADC::_sample(unsigned channel)
{
perf_begin(_sample_perf);
/* clear any previous EOC */
if (rSR & ADC_SR_EOC)
rSR &= ~ADC_SR_EOC;
/* run a single conversion right now - should take about 60 cycles (a few microseconds) max */
rSQR3 = channel;
rCR2 |= ADC_CR2_SWSTART;
/* wait for the conversion to complete */
hrt_abstime now = hrt_absolute_time();
while (!(rSR & ADC_SR_EOC)) {
/* don't wait for more than 50us, since that means something broke - should reset here if we see this */
if ((hrt_absolute_time() - now) > 50) {
log("sample timeout");
return 0xffff;
}
}
/* read the result and clear EOC */
uint16_t result = rDR;
perf_end(_sample_perf);
return result;
}
/*
* Driver 'main' command.
*/
extern "C" __EXPORT int adc_main(int argc, char *argv[]);
namespace
{
ADC *g_adc;
void
test(void)
{
int fd = open(ADC_DEVICE_PATH, O_RDONLY);
if (fd < 0)
err(1, "can't open ADC device");
for (unsigned i = 0; i < 50; i++) {
adc_msg_s data[8];
ssize_t count = read(fd, data, sizeof(data));
if (count < 0)
errx(1, "read error");
unsigned channels = count / sizeof(data[0]);
for (unsigned j = 0; j < channels; j++) {
printf ("%d: %u ", data[j].am_channel, data[j].am_data);
}
printf("\n");
usleep(500000);
}
exit(0);
}
}
int
adc_main(int argc, char *argv[])
{
if (g_adc == nullptr) {
/* XXX this hardcodes the default channel set for PX4FMU - should be configurable */
g_adc = new ADC((1 << 10) | (1 << 11) | (1 << 12) | (1 << 13));
if (g_adc == nullptr)
errx(1, "couldn't allocate the ADC driver");
if (g_adc->init() != OK) {
delete g_adc;
errx(1, "ADC init failed");
}
}
if (argc > 1) {
if (!strcmp(argv[1], "test"))
test();
}
exit(0);
}