394 lines
11 KiB
C
394 lines
11 KiB
C
/*
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* Copyright (c) 2018, Cue Health Inc
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <nrfx_pwm.h>
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#include <drivers/pwm.h>
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#include <hal/nrf_gpio.h>
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#include <stdbool.h>
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#define LOG_LEVEL CONFIG_PWM_LOG_LEVEL
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#include <logging/log.h>
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LOG_MODULE_REGISTER(pwm_nrfx);
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#define PWM_NRFX_CH_POLARITY_MASK BIT(15)
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#define PWM_NRFX_CH_PULSE_CYCLES_MASK BIT_MASK(15)
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#define PWM_NRFX_CH_VALUE_NORMAL PWM_NRFX_CH_POLARITY_MASK
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#define PWM_NRFX_CH_VALUE_INVERTED (0)
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#define PWM_NRFX_CH_PIN_MASK ~NRFX_PWM_PIN_INVERTED
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struct pwm_nrfx_config {
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nrfx_pwm_t pwm;
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nrfx_pwm_config_t initial_config;
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nrf_pwm_sequence_t seq;
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};
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struct pwm_nrfx_data {
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uint32_t period_cycles;
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uint16_t current[NRF_PWM_CHANNEL_COUNT];
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uint16_t countertop;
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uint8_t prescaler;
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};
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static int pwm_period_check_and_set(const struct pwm_nrfx_config *config,
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struct pwm_nrfx_data *data,
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uint32_t channel,
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uint32_t period_cycles)
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{
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uint8_t i;
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uint8_t prescaler;
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uint32_t countertop;
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/* If any other channel (other than the one being configured) is set up
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* with a non-zero pulse cycle, the period that is currently set cannot
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* be changed, as this would influence the output for this channel.
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*/
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for (i = 0; i < NRF_PWM_CHANNEL_COUNT; ++i) {
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if (i != channel) {
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uint16_t channel_pulse_cycle =
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data->current[i]
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& PWM_NRFX_CH_PULSE_CYCLES_MASK;
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if (channel_pulse_cycle > 0) {
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LOG_ERR("Incompatible period.");
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return -EINVAL;
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}
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}
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}
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/* Try to find a prescaler that will allow setting the requested period
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* after prescaling as the countertop value for the PWM peripheral.
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*/
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prescaler = 0;
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countertop = period_cycles;
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do {
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if (countertop <= PWM_COUNTERTOP_COUNTERTOP_Msk) {
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data->period_cycles = period_cycles;
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data->prescaler = prescaler;
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data->countertop = (uint16_t)countertop;
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nrf_pwm_configure(config->pwm.p_registers,
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data->prescaler,
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config->initial_config.count_mode,
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data->countertop);
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return 0;
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}
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countertop >>= 1;
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++prescaler;
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} while (prescaler <= PWM_PRESCALER_PRESCALER_Msk);
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LOG_ERR("Prescaler for period_cycles %u not found.", period_cycles);
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return -EINVAL;
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}
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static uint8_t pwm_channel_map(const uint8_t *output_pins, uint32_t pwm)
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{
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uint8_t i;
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/* Find pin, return channel number */
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for (i = 0U; i < NRF_PWM_CHANNEL_COUNT; i++) {
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if (output_pins[i] != NRFX_PWM_PIN_NOT_USED
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&& (pwm == (output_pins[i] & PWM_NRFX_CH_PIN_MASK))) {
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return i;
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}
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}
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/* Return NRF_PWM_CHANNEL_COUNT to show that PWM pin was not found. */
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return NRF_PWM_CHANNEL_COUNT;
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}
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static bool pwm_channel_is_active(uint8_t channel,
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const struct pwm_nrfx_data *data)
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{
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uint16_t pulse_cycle =
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data->current[channel] & PWM_NRFX_CH_PULSE_CYCLES_MASK;
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return (pulse_cycle > 0 && pulse_cycle < data->countertop);
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}
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static bool any_other_channel_is_active(uint8_t channel,
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const struct pwm_nrfx_data *data)
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{
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uint8_t i;
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for (i = 0; i < NRF_PWM_CHANNEL_COUNT; ++i) {
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if (i != channel && pwm_channel_is_active(i, data)) {
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return true;
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}
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}
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return false;
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}
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static int pwm_nrfx_pin_set(const struct device *dev, uint32_t pwm,
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uint32_t period_cycles, uint32_t pulse_cycles,
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pwm_flags_t flags)
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{
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/* We assume here that period_cycles will always be 16MHz
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* peripheral clock. Since pwm_nrfx_get_cycles_per_sec() function might
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* be removed, see ISSUE #6958.
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* TODO: Remove this comment when issue has been resolved.
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*/
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const struct pwm_nrfx_config *config = dev->config;
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struct pwm_nrfx_data *data = dev->data;
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uint8_t channel;
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bool was_stopped;
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if (flags) {
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/* PWM polarity not supported (yet?) */
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return -ENOTSUP;
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}
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/* Check if PWM pin is one of the predefiend DTS config pins.
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* Return its array index (channel number),
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* or NRF_PWM_CHANNEL_COUNT if not initialized through DTS.
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*/
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channel = pwm_channel_map(config->initial_config.output_pins, pwm);
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if (channel == NRF_PWM_CHANNEL_COUNT) {
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LOG_ERR("PWM pin %d not enabled through DTS configuration.",
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pwm);
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return -EINVAL;
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}
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/* Check if nrfx_pwm_stop function was called in previous
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* pwm_nrfx_pin_set call. Relying only on state returned by
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* nrfx_pwm_is_stopped may cause race condition if the pwm_nrfx_pin_set
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* is called multiple times in quick succession.
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*/
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was_stopped = !pwm_channel_is_active(channel, data) &&
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!any_other_channel_is_active(channel, data);
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/* If this PWM is in center-aligned mode, pulse and period lengths
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* are effectively doubled by the up-down count, so halve them here
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* to compensate.
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*/
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if (config->initial_config.count_mode == NRF_PWM_MODE_UP_AND_DOWN) {
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period_cycles /= 2;
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pulse_cycles /= 2;
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}
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/* Check if period_cycles is either matching currently used, or
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* possible to use with our prescaler options.
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* Don't do anything if the period length happens to be zero.
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* In such case, pulse cycles will be right below limited to 0
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* and this will result in making the channel inactive.
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*/
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if (period_cycles != 0 && period_cycles != data->period_cycles) {
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int ret = pwm_period_check_and_set(config, data, channel,
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period_cycles);
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if (ret) {
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return ret;
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}
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}
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/* Limit pulse cycles to period cycles (meaning 100% duty), bigger
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* values might not fit after prescaling into the 15-bit field that
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* is filled below.
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*/
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pulse_cycles = MIN(pulse_cycles, period_cycles);
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/* Store new pulse value bit[14:0], and polarity bit[15] for channel. */
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data->current[channel] = (
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(data->current[channel] & PWM_NRFX_CH_POLARITY_MASK)
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| (pulse_cycles >> data->prescaler));
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LOG_DBG("pin %u, pulse %u, period %u, prescaler: %u.",
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pwm, pulse_cycles, period_cycles, data->prescaler);
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/* If this channel turns out to not need to be driven by the PWM
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* peripheral (it is off or fully on - duty 0% or 100%), set properly
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* the GPIO configuration for its output pin. This will provide
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* the correct output state for this channel when the PWM peripheral
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* is disabled after all channels appear to be inactive.
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*/
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if (!pwm_channel_is_active(channel, data)) {
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/* If pulse 0% and pin not inverted, set LOW.
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* If pulse 100% and pin inverted, set LOW.
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* If pulse 0% and pin inverted, set HIGH.
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* If pulse 100% and pin not inverted, set HIGH.
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*/
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bool channel_inverted_state =
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config->initial_config.output_pins[channel]
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& NRFX_PWM_PIN_INVERTED;
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bool pulse_0_and_not_inverted =
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(pulse_cycles == 0U)
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&& !channel_inverted_state;
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bool pulse_100_and_inverted =
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(pulse_cycles == period_cycles)
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&& channel_inverted_state;
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if (pulse_0_and_not_inverted || pulse_100_and_inverted) {
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nrf_gpio_pin_clear(pwm);
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} else {
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nrf_gpio_pin_set(pwm);
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}
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if (!any_other_channel_is_active(channel, data)) {
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nrfx_pwm_stop(&config->pwm, false);
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}
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} else {
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/* Since we are playing the sequence in a loop, the
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* sequence only has to be started when its not already
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* playing. The new channel values will be used
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* immediately when they are written into the seq array.
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*/
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if (was_stopped) {
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/* Wait until PWM will be stopped and then start the
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* sequence.
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*/
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while (!nrfx_pwm_is_stopped(&config->pwm)) {
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}
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nrfx_pwm_simple_playback(&config->pwm,
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&config->seq,
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1,
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NRFX_PWM_FLAG_LOOP);
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}
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}
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return 0;
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}
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static int pwm_nrfx_get_cycles_per_sec(const struct device *dev, uint32_t pwm,
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uint64_t *cycles)
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{
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/* TODO: Since this function might be removed, we will always return
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* 16MHz from this function and handle the conversion with prescaler,
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* etc, in the pin set function. See issue #6958.
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*/
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*cycles = 16ul * 1000ul * 1000ul;
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return 0;
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}
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static const struct pwm_driver_api pwm_nrfx_drv_api_funcs = {
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.pin_set = pwm_nrfx_pin_set,
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.get_cycles_per_sec = pwm_nrfx_get_cycles_per_sec,
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};
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static int pwm_nrfx_init(const struct device *dev)
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{
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const struct pwm_nrfx_config *config = dev->config;
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nrfx_err_t result = nrfx_pwm_init(&config->pwm,
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&config->initial_config,
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NULL,
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NULL);
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if (result != NRFX_SUCCESS) {
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LOG_ERR("Failed to initialize device: %s", dev->name);
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return -EBUSY;
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}
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return 0;
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}
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#ifdef CONFIG_PM_DEVICE
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static void pwm_nrfx_uninit(const struct device *dev)
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{
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const struct pwm_nrfx_config *config = dev->config;
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nrfx_pwm_uninit(&config->pwm);
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memset(dev->data, 0, sizeof(struct pwm_nrfx_data));
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}
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static int pwm_nrfx_pm_action(const struct device *dev,
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enum pm_device_action action)
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{
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int err = 0;
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switch (action) {
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case PM_DEVICE_ACTION_RESUME:
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err = pwm_nrfx_init(dev);
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break;
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case PM_DEVICE_ACTION_SUSPEND:
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pwm_nrfx_uninit(dev);
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break;
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default:
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return -ENOTSUP;
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}
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return err;
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}
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#else
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#define pwm_nrfx_pm_action NULL
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#endif /* CONFIG_PM_DEVICE */
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#define PWM(dev_idx) DT_NODELABEL(pwm##dev_idx)
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#define PWM_PROP(dev_idx, prop) DT_PROP(PWM(dev_idx), prop)
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#define PWM_NRFX_IS_INVERTED(dev_idx, ch_idx) \
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PWM_PROP(dev_idx, ch##ch_idx##_inverted)
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#define PWM_NRFX_CH_PIN(dev_idx, ch_idx) \
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COND_CODE_1(DT_NODE_HAS_PROP(PWM(dev_idx), ch##ch_idx##_pin), \
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(PWM_PROP(dev_idx, ch##ch_idx##_pin)), \
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(NRFX_PWM_PIN_NOT_USED))
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#define PWM_NRFX_OUTPUT_PIN(dev_idx, ch_idx) \
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(PWM_NRFX_CH_PIN(dev_idx, ch_idx) | \
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(PWM_NRFX_IS_INVERTED(dev_idx, ch_idx) ? NRFX_PWM_PIN_INVERTED : 0))
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#define PWM_NRFX_DEFAULT_VALUE(dev_idx, ch_idx) \
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(PWM_NRFX_IS_INVERTED(dev_idx, ch_idx) ? \
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PWM_NRFX_CH_VALUE_INVERTED : PWM_NRFX_CH_VALUE_NORMAL)
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#define PWM_NRFX_COUNT_MODE(dev_idx) \
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(PWM_PROP(dev_idx, center_aligned) ? \
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NRF_PWM_MODE_UP_AND_DOWN : NRF_PWM_MODE_UP)
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#define PWM_NRFX_DEVICE(idx) \
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static struct pwm_nrfx_data pwm_nrfx_##idx##_data = { \
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.current = { \
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PWM_NRFX_DEFAULT_VALUE(idx, 0), \
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PWM_NRFX_DEFAULT_VALUE(idx, 1), \
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PWM_NRFX_DEFAULT_VALUE(idx, 2), \
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PWM_NRFX_DEFAULT_VALUE(idx, 3), \
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} \
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}; \
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static const struct pwm_nrfx_config pwm_nrfx_##idx##config = { \
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.pwm = NRFX_PWM_INSTANCE(idx), \
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.initial_config = { \
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.output_pins = { \
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PWM_NRFX_OUTPUT_PIN(idx, 0), \
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PWM_NRFX_OUTPUT_PIN(idx, 1), \
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PWM_NRFX_OUTPUT_PIN(idx, 2), \
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PWM_NRFX_OUTPUT_PIN(idx, 3), \
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}, \
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.base_clock = NRF_PWM_CLK_1MHz, \
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.count_mode = PWM_NRFX_COUNT_MODE(idx), \
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.top_value = 1000, \
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.load_mode = NRF_PWM_LOAD_INDIVIDUAL, \
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.step_mode = NRF_PWM_STEP_TRIGGERED, \
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}, \
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.seq.values.p_raw = pwm_nrfx_##idx##_data.current, \
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.seq.length = NRF_PWM_CHANNEL_COUNT \
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}; \
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PM_DEVICE_DT_DEFINE(PWM(idx), pwm_nrfx_pm_action); \
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DEVICE_DT_DEFINE(PWM(idx), \
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pwm_nrfx_init, PM_DEVICE_DT_REF(PWM(idx)), \
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&pwm_nrfx_##idx##_data, \
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&pwm_nrfx_##idx##config, \
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POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE, \
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&pwm_nrfx_drv_api_funcs)
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#if DT_NODE_HAS_STATUS(DT_NODELABEL(pwm0), okay)
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PWM_NRFX_DEVICE(0);
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#endif
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#if DT_NODE_HAS_STATUS(DT_NODELABEL(pwm1), okay)
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PWM_NRFX_DEVICE(1);
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#endif
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#if DT_NODE_HAS_STATUS(DT_NODELABEL(pwm2), okay)
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PWM_NRFX_DEVICE(2);
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#endif
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#if DT_NODE_HAS_STATUS(DT_NODELABEL(pwm3), okay)
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PWM_NRFX_DEVICE(3);
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#endif
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