1ca6828db9
Replace device_get_binding with DEVICE_DT_GET for getting access to the pwm controller device. Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
93 lines
2.2 KiB
C
93 lines
2.2 KiB
C
/*
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* Copyright (c) 2016 Intel Corporation
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* Copyright (c) 2020 Nordic Semiconductor ASA
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file Sample app to demonstrate PWM.
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*/
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#include <zephyr.h>
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#include <sys/printk.h>
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#include <device.h>
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#include <drivers/pwm.h>
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#define PWM_LED0_NODE DT_ALIAS(pwm_led0)
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#if DT_NODE_HAS_STATUS(PWM_LED0_NODE, okay)
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#define PWM_CTLR DT_PWMS_CTLR(PWM_LED0_NODE)
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#define PWM_CHANNEL DT_PWMS_CHANNEL(PWM_LED0_NODE)
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#define PWM_FLAGS DT_PWMS_FLAGS(PWM_LED0_NODE)
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#else
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#error "Unsupported board: pwm-led0 devicetree alias is not defined"
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#define PWM_CTLR DT_INVALID_NODE
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#define PWM_CHANNEL 0
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#define PWM_FLAGS 0
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#endif
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#define MIN_PERIOD_USEC (USEC_PER_SEC / 64U)
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#define MAX_PERIOD_USEC USEC_PER_SEC
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void main(void)
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{
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const struct device *pwm;
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uint32_t max_period;
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uint32_t period;
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uint8_t dir = 0U;
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int ret;
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printk("PWM-based blinky\n");
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pwm = DEVICE_DT_GET(PWM_CTLR);
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if (!device_is_ready(pwm)) {
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printk("Error: PWM device %s is not ready\n", pwm->name);
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return;
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}
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/*
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* In case the default MAX_PERIOD_USEC value cannot be set for
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* some PWM hardware, decrease its value until it can.
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*
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* Keep its value at least MIN_PERIOD_USEC * 4 to make sure
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* the sample changes frequency at least once.
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*/
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printk("Calibrating for channel %d...\n", PWM_CHANNEL);
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max_period = MAX_PERIOD_USEC;
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while (pwm_pin_set_usec(pwm, PWM_CHANNEL,
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max_period, max_period / 2U, PWM_FLAGS)) {
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max_period /= 2U;
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if (max_period < (4U * MIN_PERIOD_USEC)) {
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printk("Error: PWM device "
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"does not support a period at least %u\n",
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4U * MIN_PERIOD_USEC);
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return;
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}
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}
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printk("Done calibrating; maximum/minimum periods %u/%u usec\n",
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max_period, MIN_PERIOD_USEC);
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period = max_period;
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while (1) {
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ret = pwm_pin_set_usec(pwm, PWM_CHANNEL,
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period, period / 2U, PWM_FLAGS);
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if (ret) {
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printk("Error %d: failed to set pulse width\n", ret);
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return;
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}
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period = dir ? (period * 2U) : (period / 2U);
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if (period > max_period) {
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period = max_period / 2U;
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dir = 0U;
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} else if (period < MIN_PERIOD_USEC) {
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period = MIN_PERIOD_USEC * 2U;
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dir = 1U;
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}
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k_sleep(K_SECONDS(4U));
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}
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}
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