pwm_input: added PWM input driver

this allows for input of PWM signals on the FMUv2 aux5 pins

2 files changed, 644 insertions, 0 deletions

diff --git a/src/drivers/pwm_input/module.mk b/src/drivers/pwm_input/module.mk
new file mode 100644
index 000000000..04f04d6cb
--- /dev/null
+++ b/src/drivers/pwm_input/module.mk
@@ -0,0 +1,41 @@
+############################################################################
+#
+#   Copyright (c) 2012, 2013 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.
+#
+############################################################################
+
+#
+# Makefile to build the PWM input driver.
+#
+
+MODULE_COMMAND	= pwm_input
+
+SRCS		= pwm_input.cpp
+
diff --git a/src/drivers/pwm_input/pwm_input.cpp b/src/drivers/pwm_input/pwm_input.cpp
new file mode 100644
index 000000000..2d771266c
--- /dev/null
+++ b/src/drivers/pwm_input/pwm_input.cpp
@@ -0,0 +1,603 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2015 Andrew Tridgell. 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 pwm_input.cpp 
+ *
+ * PWM input driver based on earlier driver from Evan Slatyer,
+ * which in turn was based on drv_hrt.c
+ */
+
+#include <nuttx/config.h>
+#include <nuttx/arch.h>
+#include <nuttx/irq.h>
+
+#include <sys/types.h>
+#include <stdbool.h>
+
+#include <assert.h>
+#include <debug.h>
+#include <time.h>
+#include <queue.h>
+#include <errno.h>
+#include <string.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <board_config.h>
+#include <drivers/drv_pwm_input.h>
+#include <drivers/drv_hrt.h>
+
+#include "chip.h"
+#include "up_internal.h"
+#include "up_arch.h"
+
+#include "stm32.h"
+#include "stm32_gpio.h"
+#include "stm32_tim.h"
+#include <systemlib/err.h>
+
+#include <uORB/uORB.h>
+#include <uORB/topics/pwm_input.h>
+#include <uORB/topics/subsystem_info.h>
+
+#include <drivers/drv_device.h>
+#include <drivers/device/device.h>
+#include <drivers/device/ringbuffer.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#if HRT_TIMER == PWMIN_TIMER
+#error cannot share timer between HRT and PWMIN
+#endif
+
+#if !defined(GPIO_PWM_IN) || !defined(PWMIN_TIMER) || !defined(PWMIN_TIMER_CHANNEL)
+#error PWMIN defines are needed in board_config.h for this board
+#endif
+
+/* PWMIN configuration */
+#if   PWMIN_TIMER == 1
+# define PWMIN_TIMER_BASE	STM32_TIM1_BASE
+# define PWMIN_TIMER_POWER_REG	STM32_RCC_APB2ENR
+# define PWMIN_TIMER_POWER_BIT	RCC_APB2ENR_TIM1EN
+# define PWMIN_TIMER_VECTOR	STM32_IRQ_TIM1CC
+# define PWMIN_TIMER_CLOCK	STM32_APB2_TIM1_CLKIN
+#elif PWMIN_TIMER == 2
+# define PWMIN_TIMER_BASE	STM32_TIM2_BASE
+# define PWMIN_TIMER_POWER_REG	STM32_RCC_APB1ENR
+# define PWMIN_TIMER_POWER_BIT	RCC_APB2ENR_TIM2EN
+# define PWMIN_TIMER_VECTOR	STM32_IRQ_TIM2
+# define PWMIN_TIMER_CLOCK	STM32_APB1_TIM2_CLKIN
+#elif PWMIN_TIMER == 3
+# define PWMIN_TIMER_BASE	STM32_TIM3_BASE
+# define PWMIN_TIMER_POWER_REG	STM32_RCC_APB1ENR
+# define PWMIN_TIMER_POWER_BIT	RCC_APB1ENR_TIM3EN
+# define PWMIN_TIMER_VECTOR	STM32_IRQ_TIM3
+# define PWMIN_TIMER_CLOCK	STM32_APB1_TIM3_CLKIN
+#elif PWMIN_TIMER == 4
+# define PWMIN_TIMER_BASE	STM32_TIM4_BASE
+# define PWMIN_TIMER_POWER_REG	STM32_RCC_APB1ENR
+# define PWMIN_TIMER_POWER_BIT	RCC_APB1ENR_TIM4EN
+# define PWMIN_TIMER_VECTOR	STM32_IRQ_TIM4
+# define PWMIN_TIMER_CLOCK	STM32_APB1_TIM4_CLKIN
+#elif PWMIN_TIMER == 5
+# define PWMIN_TIMER_BASE	STM32_TIM5_BASE
+# define PWMIN_TIMER_POWER_REG	STM32_RCC_APB1ENR
+# define PWMIN_TIMER_POWER_BIT	RCC_APB2ENR_TIM5EN
+# define PWMIN_TIMER_VECTOR	STM32_IRQ_TIM5
+# define PWMIN_TIMER_CLOCK	STM32_APB1_TIM5_CLKIN
+#elif PWMIN_TIMER == 8
+# define PWMIN_TIMER_BASE	STM32_TIM8_BASE
+# define PWMIN_TIMER_POWER_REG	STM32_RCC_APB2ENR
+# define PWMIN_TIMER_POWER_BIT	RCC_APB2ENR_TIM8EN
+# define PWMIN_TIMER_VECTOR	STM32_IRQ_TIM8CC
+# define PWMIN_TIMER_CLOCK	STM32_APB2_TIM8_CLKIN
+#elif PWMIN_TIMER == 9
+# define PWMIN_TIMER_BASE	STM32_TIM9_BASE
+# define PWMIN_TIMER_POWER_REG	STM32_RCC_APB1ENR
+# define PWMIN_TIMER_POWER_BIT	RCC_APB2ENR_TIM9EN
+# define PWMIN_TIMER_VECTOR	STM32_IRQ_TIM1BRK
+# define PWMIN_TIMER_CLOCK	STM32_APB1_TIM9_CLKIN
+#elif PWMIN_TIMER == 10
+# define PWMIN_TIMER_BASE	STM32_TIM10_BASE
+# define PWMIN_TIMER_POWER_REG	STM32_RCC_APB1ENR
+# define PWMIN_TIMER_POWER_BIT	RCC_APB2ENR_TIM10EN
+# define PWMIN_TIMER_VECTOR	STM32_IRQ_TIM1UP
+# define PWMIN_TIMER_CLOCK	STM32_APB2_TIM10_CLKIN
+#elif PWMIN_TIMER == 11
+# define PWMIN_TIMER_BASE	STM32_TIM11_BASE
+# define PWMIN_TIMER_POWER_REG	STM32_RCC_APB1ENR
+# define PWMIN_TIMER_POWER_BIT	RCC_APB2ENR_TIM11EN
+# define PWMIN_TIMER_VECTOR	STM32_IRQ_TIM1TRGCOM
+# define PWMIN_TIMER_CLOCK	STM32_APB2_TIM11_CLKIN
+#elif PWMIN_TIMER == 12
+# define PWMIN_TIMER_BASE	STM32_TIM12_BASE
+# define PWMIN_TIMER_POWER_REG	STM32_RCC_APB1ENR
+# define PWMIN_TIMER_POWER_BIT	RCC_APB2ENR_TIM12EN
+# define PWMIN_TIMER_VECTOR	STM32_IRQ_TIM1TRGCOM
+# define PWMIN_TIMER_CLOCK	STM32_APB2_TIM12_CLKIN
+#else
+# error PWMIN_TIMER must be a value between 1 and 12
+#endif
+
+/*
+ * HRT clock must be at least 1MHz
+ */
+#if PWMIN_TIMER_CLOCK <= 1000000
+# error PWMIN_TIMER_CLOCK must be greater than 1MHz
+#endif
+
+/*
+ * Timer register accessors
+ */
+#define REG(_reg)	(*(volatile uint32_t *)(PWMIN_TIMER_BASE + _reg))
+
+#define rCR1		REG(STM32_GTIM_CR1_OFFSET)
+#define rCR2		REG(STM32_GTIM_CR2_OFFSET)
+#define rSMCR		REG(STM32_GTIM_SMCR_OFFSET)
+#define rDIER		REG(STM32_GTIM_DIER_OFFSET)
+#define rSR		REG(STM32_GTIM_SR_OFFSET)
+#define rEGR		REG(STM32_GTIM_EGR_OFFSET)
+#define rCCMR1		REG(STM32_GTIM_CCMR1_OFFSET)
+#define rCCMR2		REG(STM32_GTIM_CCMR2_OFFSET)
+#define rCCER		REG(STM32_GTIM_CCER_OFFSET)
+#define rCNT		REG(STM32_GTIM_CNT_OFFSET)
+#define rPSC		REG(STM32_GTIM_PSC_OFFSET)
+#define rARR		REG(STM32_GTIM_ARR_OFFSET)
+#define rCCR1		REG(STM32_GTIM_CCR1_OFFSET)
+#define rCCR2		REG(STM32_GTIM_CCR2_OFFSET)
+#define rCCR3		REG(STM32_GTIM_CCR3_OFFSET)
+#define rCCR4		REG(STM32_GTIM_CCR4_OFFSET)
+#define rDCR		REG(STM32_GTIM_DCR_OFFSET)
+#define rDMAR		REG(STM32_GTIM_DMAR_OFFSET)
+
+/*
+ * Specific registers and bits used by HRT sub-functions
+ */
+#if PWMIN_TIMER_CHANNEL == 1
+ #define rCCR_PWMIN_A		rCCR1			/* compare register for PWMIN */
+ #define DIER_PWMIN_A		(GTIM_DIER_CC1IE) 	/* interrupt enable for PWMIN */
+ #define SR_INT_PWMIN_A		GTIM_SR_CC1IF		/* interrupt status for PWMIN */
+ #define rCCR_PWMIN_B		rCCR2 			/* compare register for PWMIN */
+ #define SR_INT_PWMIN_B		GTIM_SR_CC2IF		/* interrupt status for PWMIN */
+ #define CCMR1_PWMIN		((0x02 << GTIM_CCMR1_CC2S_SHIFT) | (0x01 << GTIM_CCMR1_CC1S_SHIFT))
+ #define CCMR2_PWMIN		0
+ #define CCER_PWMIN		(GTIM_CCER_CC2P | GTIM_CCER_CC1E | GTIM_CCER_CC2E)
+ #define SR_OVF_PWMIN		(GTIM_SR_CC1OF | GTIM_SR_CC2OF)
+ #define SMCR_PWMIN_1		(0x05 << GTIM_SMCR_TS_SHIFT)
+ #define SMCR_PWMIN_2		((0x04 << GTIM_SMCR_SMS_SHIFT) | SMCR_PWMIN_1)
+#elif PWMIN_TIMER_CHANNEL == 2
+ #define rCCR_PWMIN_A		rCCR2			/* compare register for PWMIN */
+ #define DIER_PWMIN_A		(GTIM_DIER_CC2IE)	/* interrupt enable for PWMIN */
+ #define SR_INT_PWMIN_A		GTIM_SR_CC2IF		/* interrupt status for PWMIN */
+ #define rCCR_PWMIN_B		rCCR1			/* compare register for PWMIN */
+ #define DIER_PWMIN_B		GTIM_DIER_CC1IE		/* interrupt enable for PWMIN */
+ #define SR_INT_PWMIN_B		GTIM_SR_CC1IF		/* interrupt status for PWMIN */
+ #define CCMR1_PWMIN		((0x01 << GTIM_CCMR1_CC2S_SHIFT) | (0x02 << GTIM_CCMR1_CC1S_SHIFT))
+ #define CCMR2_PWMIN		0
+ #define CCER_PWMIN		(GTIM_CCER_CC1P | GTIM_CCER_CC1E | GTIM_CCER_CC2E)
+ #define SR_OVF_PWMIN		(GTIM_SR_CC1OF | GTIM_SR_CC2OF)
+ #define SMCR_PWMIN_1		(0x06 << GTIM_SMCR_TS_SHIFT)
+ #define SMCR_PWMIN_2		((0x04 << GTIM_SMCR_SMS_SHIFT) | SMCR_PWMIN_1)
+#else
+ #error PWMIN_TIMER_CHANNEL must be either 1 and 2.
+#endif
+
+
+class PWMIN : device::CDev
+{
+public:
+	PWMIN();
+	virtual ~PWMIN();
+
+	virtual int init();
+	virtual int open(struct file *filp);
+	virtual ssize_t read(struct file *filp, char *buffer, size_t buflen);
+	virtual int ioctl(struct file *filp, int cmd, unsigned long arg);
+
+	void _publish(uint16_t status, uint32_t period, uint32_t pulse_width);
+	void _print_info(void);
+
+private:
+	uint32_t error_count;
+	uint32_t pulses_captured;
+	uint32_t last_period;
+	uint32_t last_width;
+	RingBuffer *reports;
+	bool timer_started;
+
+	void timer_init(void);
+};
+
+static int pwmin_tim_isr(int irq, void *context);
+static void pwmin_start(void);
+static void pwmin_info(void);
+static void pwmin_test(void);
+static void pwmin_reset(void);
+
+static PWMIN *g_dev;
+
+PWMIN::PWMIN() :
+	CDev("pwmin", PWMIN0_DEVICE_PATH),
+	error_count(0),
+	pulses_captured(0),
+	last_period(0),
+	last_width(0),
+	reports(nullptr),
+	timer_started(false)
+{
+}
+
+PWMIN::~PWMIN()
+{
+	if (reports != nullptr)
+		delete reports;
+}
+
+/*
+  initialise the driver. This doesn't actually start the timer (that
+  is done on open). We don't start the timer to allow for this driver
+  to be started in init scripts when the user may be using the input
+  pin as PWM output
+ */
+int
+PWMIN::init()
+{
+	// we just register the device in /dev, and only actually
+	// activate the timer when requested to when the device is opened
+	CDev::init();
+
+	reports = new RingBuffer(2, sizeof(struct pwm_input_s));
+	if (reports == nullptr) {
+		return -ENOMEM;
+	}
+
+	return OK;
+}
+
+/*
+ * Initialise the timer we are going to use.
+ */
+void PWMIN::timer_init(void) 
+{
+	// run with interrupts disabled in case the timer is already
+	// setup. We don't want it firing while we are doing the setup
+	irqstate_t flags = irqsave();
+	stm32_configgpio(GPIO_PWM_IN);
+
+	/* claim our interrupt vector */
+	irq_attach(PWMIN_TIMER_VECTOR, pwmin_tim_isr);
+
+	/* Clear no bits, set timer enable bit.*/
+	modifyreg32(PWMIN_TIMER_POWER_REG, 0, PWMIN_TIMER_POWER_BIT); 
+
+	/* disable and configure the timer */
+	rCR1 = 0;
+	rCR2 = 0;
+	rSMCR = 0;
+	rDIER = DIER_PWMIN_A;
+	rCCER = 0;		/* unlock CCMR* registers */
+	rCCMR1 = CCMR1_PWMIN;
+	rCCMR2 = CCMR2_PWMIN;
+	rSMCR = SMCR_PWMIN_1;	/* Set up mode */
+	rSMCR = SMCR_PWMIN_2;	/* Enable slave mode controller */
+	rCCER = CCER_PWMIN;
+	rDCR = 0;
+
+	// for simplicity scale by the clock in MHz. This gives us
+	// readings in microseconds which is typically what is needed
+	// for a PWM input driver
+	uint32_t prescaler = PWMIN_TIMER_CLOCK/1000000UL;
+
+	/* 
+	 * define the clock speed. We want the highest possible clock 
+	 * speed that avoids overflows.
+	 */
+	rPSC = prescaler - 1;
+
+	/* run the full span of the counter. All timers can handle
+	 * uint16 */
+	rARR = UINT16_MAX;
+
+	/* generate an update event; reloads the counter, all registers */
+	rEGR = GTIM_EGR_UG;
+
+	/* enable the timer */
+	rCR1 = GTIM_CR1_CEN;
+
+	/* enable interrupts */
+	up_enable_irq(PWMIN_TIMER_VECTOR);
+
+	irqrestore(flags);
+
+	timer_started = true;
+}
+
+/*
+  hook for open of the driver. We start the timer at this point, then
+  leave it running
+ */
+int
+PWMIN::open(struct file *filp)
+{
+	if (g_dev == nullptr) {
+		return -EIO;
+	}
+	int ret = CDev::open(filp);	
+	if (ret == OK && !timer_started) {
+		g_dev->timer_init();
+	}
+	return ret;
+}
+
+
+/*
+  handle ioctl requests
+ */
+int
+PWMIN::ioctl(struct file *filp, int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case SENSORIOCSQUEUEDEPTH: {
+			/* lower bound is mandatory, upper bound is a sanity check */
+			if ((arg < 1) || (arg > 500))
+				return -EINVAL;
+
+			irqstate_t flags = irqsave();
+			if (!reports->resize(arg)) {
+				irqrestore(flags);
+				return -ENOMEM;
+			}
+			irqrestore(flags);
+
+			return OK;
+		}
+
+	case SENSORIOCGQUEUEDEPTH:
+		return reports->size();
+
+	case SENSORIOCRESET:
+		/* user has asked for the timer to be reset. This may
+		   be needed if the pin was used for a different
+		   purpose (such as PWM output)
+		*/
+		timer_init();
+		return OK;
+
+	default:
+		/* give it to the superclass */
+		return CDev::ioctl(filp, cmd, arg);
+	}
+}
+
+
+/*
+  read some samples from the device
+ */
+ssize_t
+PWMIN::read(struct file *filp, char *buffer, size_t buflen)
+{
+	unsigned count = buflen / sizeof(struct pwm_input_s);
+	struct pwm_input_s *buf = reinterpret_cast<struct pwm_input_s *>(buffer);
+	int ret = 0;
+
+	/* buffer must be large enough */
+	if (count < 1)
+		return -ENOSPC;
+
+	while (count--) {
+		if (reports->get(buf)) {
+			ret += sizeof(struct pwm_input_s);
+			buf++;
+		}
+	}
+
+	/* if there was no data, warn the caller */
+	return ret ? ret : -EAGAIN;
+}
+
+/*
+  publish some data from the ISR in the ring buffer
+ */
+void PWMIN::_publish(uint16_t status, uint32_t period, uint32_t pulse_width)
+{
+	/* if we missed an edge, we have to give up */
+	if (status & SR_OVF_PWMIN) {
+		error_count++;
+		return;
+	}
+
+	struct pwm_input_s pwmin_report;
+	pwmin_report.timestamp = hrt_absolute_time();
+	pwmin_report.error_count = error_count;
+	pwmin_report.period = period;
+	pwmin_report.pulse_width = pulse_width;
+
+	reports->force(&pwmin_report);
+
+	last_period = period;
+	last_width = pulse_width;
+	pulses_captured++;
+}
+
+/*
+  print information on the last captured
+ */
+void PWMIN::_print_info(void)
+{
+	if (!timer_started) {
+		printf("timer not started - try the 'test' command\n");
+	} else {
+		printf("count=%u period=%u width=%u\n",
+		       (unsigned)pulses_captured,
+		       (unsigned)last_period,
+		       (unsigned)last_width);
+	}
+}
+
+
+/*
+  Handle the interupt, gathering pulse data
+ */
+static int pwmin_tim_isr(int irq, void *context)
+{
+	uint16_t status = rSR;
+	uint32_t period = rCCR_PWMIN_A;
+	uint32_t pulse_width = rCCR_PWMIN_B;
+
+	/* ack the interrupts we just read */
+	rSR = 0;
+
+	if (g_dev != nullptr) {
+		g_dev->_publish(status, period, pulse_width);
+	}
+
+	return OK;
+}
+
+/*
+  start the driver
+ */
+static void pwmin_start(void)
+{
+	if (g_dev != nullptr) {
+		printf("driver already started\n");
+		exit(1);
+	}
+	g_dev = new PWMIN();
+	if (g_dev == nullptr) {
+		errx(1, "driver allocation failed");
+	}
+	if (g_dev->init() != OK) {
+		errx(1, "driver init failed");
+	}
+	exit(0);
+}
+
+/*
+  test the driver
+ */
+static void pwmin_test(void)
+{
+	int fd = open(PWMIN0_DEVICE_PATH, O_RDONLY);
+	if (fd == -1) {
+		errx(1, "Failed to open device");
+	}
+	uint64_t start_time = hrt_absolute_time();
+
+	printf("Showing samples for 5 seconds\n");
+
+	while (hrt_absolute_time() < start_time+5U*1000UL*1000UL) {
+		struct pwm_input_s buf;
+		if (::read(fd, &buf, sizeof(buf)) == sizeof(buf)) {
+			printf("period=%u width=%u error_count=%u\n",
+			       (unsigned)buf.period,
+			       (unsigned)buf.pulse_width,
+			       (unsigned)buf.error_count);
+		}
+	}
+	close(fd);
+	exit(0);
+}
+
+/*
+  reset the timer
+ */
+static void pwmin_reset(void)
+{
+	int fd = open(PWMIN0_DEVICE_PATH, O_RDONLY);
+	if (fd == -1) {
+		errx(1, "Failed to open device");
+	}
+	if (ioctl(fd, SENSORIOCRESET, 0) != OK) {
+		errx(1, "reset failed");
+	}
+	close(fd);
+	exit(0);
+}
+
+/*
+  show some information on the driver
+ */
+static void pwmin_info(void)
+{
+	if (g_dev == nullptr) {
+		printf("driver not started\n");
+		exit(1);
+	}
+	g_dev->_print_info();
+	exit(0);
+}
+
+
+/*
+  driver entry point
+ */
+int pwm_input_main(int argc, char * argv[]) 
+{
+	const char *verb = argv[1];
+
+	/*
+	 * Start/load the driver.
+	 */
+	if (!strcmp(verb, "start")) {
+		pwmin_start();
+	}
+
+	/*
+	 * Print driver information.
+	 */
+	if (!strcmp(verb, "info")) {
+		pwmin_info();
+	}
+
+	/*
+	 * print test results
+	 */
+	if (!strcmp(verb, "test")) {
+		pwmin_test();
+	}
+
+	/*
+	 * reset the timer
+	 */
+	if (!strcmp(verb, "reset")) {
+		pwmin_reset();
+	}
+
+	errx(1, "unrecognized command, try 'start', 'info', 'reset' or 'test'");
+	return 0;
+}