5be0d00d41
Now that the relevant APIs generalize properly for bindings without flags, we can remove some special case checks from the tree. I couldn't find any more, but I did this kind of quickly, so it's possible I missed some. Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
81 lines
1.7 KiB
C
81 lines
1.7 KiB
C
/*
|
|
* Copyright (c) 2016 Intel Corporation
|
|
* Copyright (c) 2020 Nordic Semiconductor ASA
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*/
|
|
|
|
/**
|
|
* @file Sample app to demonstrate PWM-based LED fade
|
|
*/
|
|
|
|
#include <zephyr.h>
|
|
#include <sys/printk.h>
|
|
#include <device.h>
|
|
#include <drivers/pwm.h>
|
|
|
|
#define PWM_LED0_NODE DT_ALIAS(pwm_led0)
|
|
|
|
#if DT_NODE_HAS_STATUS(PWM_LED0_NODE, okay)
|
|
#define PWM_LABEL DT_PWMS_LABEL(PWM_LED0_NODE)
|
|
#define PWM_CHANNEL DT_PWMS_CHANNEL(PWM_LED0_NODE)
|
|
#define PWM_FLAGS DT_PWMS_FLAGS(PWM_LED0_NODE)
|
|
#else
|
|
#error "Unsupported board: pwm-led0 devicetree alias is not defined"
|
|
#define PWM_LABEL ""
|
|
#define PWM_CHANNEL 0
|
|
#define PWM_FLAGS 0
|
|
#endif
|
|
|
|
/*
|
|
* This period should be fast enough to be above the flicker fusion
|
|
* threshold. The steps should also be small enough, and happen
|
|
* quickly enough, to make the output fade change appear continuous.
|
|
*/
|
|
#define PERIOD_USEC 20000U
|
|
#define NUM_STEPS 50U
|
|
#define STEP_USEC (PERIOD_USEC / NUM_STEPS)
|
|
#define SLEEP_MSEC 25U
|
|
|
|
void main(void)
|
|
{
|
|
struct device *pwm;
|
|
uint32_t pulse_width = 0U;
|
|
uint8_t dir = 1U;
|
|
int ret;
|
|
|
|
printk("PWM-based LED fade\n");
|
|
|
|
pwm = device_get_binding(PWM_LABEL);
|
|
if (!pwm) {
|
|
printk("Error: didn't find %s device\n", PWM_LABEL);
|
|
return;
|
|
}
|
|
|
|
while (1) {
|
|
ret = pwm_pin_set_usec(pwm, PWM_CHANNEL, PERIOD_USEC,
|
|
pulse_width, PWM_FLAGS);
|
|
if (ret) {
|
|
printk("Error %d: failed to set pulse width\n", ret);
|
|
return;
|
|
}
|
|
|
|
if (dir) {
|
|
pulse_width += STEP_USEC;
|
|
if (pulse_width >= PERIOD_USEC) {
|
|
pulse_width = PERIOD_USEC - STEP_USEC;
|
|
dir = 0U;
|
|
}
|
|
} else {
|
|
if (pulse_width >= STEP_USEC) {
|
|
pulse_width -= STEP_USEC;
|
|
} else {
|
|
pulse_width = STEP_USEC;
|
|
dir = 1U;
|
|
}
|
|
}
|
|
|
|
k_sleep(K_MSEC(SLEEP_MSEC));
|
|
}
|
|
}
|