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/*
* Copyright (c) 2017 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT nordic_nrf_sw_pwm
#include <soc.h>
#include <zephyr/drivers/pwm.h>
#include <zephyr/dt-bindings/gpio/gpio.h>
#include <nrfx_gpiote.h>
#include <nrfx_ppi.h>
#include <hal/nrf_gpio.h>
#include <nrf_peripherals.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(pwm_nrf5_sw, CONFIG_PWM_LOG_LEVEL);
#define GENERATOR_NODE DT_INST_PHANDLE(0, generator)
#define GENERATOR_CC_NUM DT_PROP(GENERATOR_NODE, cc_num)
#if DT_NODE_HAS_COMPAT(GENERATOR_NODE, nordic_nrf_rtc)
#define USE_RTC 1
#define GENERATOR_ADDR ((NRF_RTC_Type *) DT_REG_ADDR(GENERATOR_NODE))
BUILD_ASSERT(DT_INST_PROP(0, clock_prescaler) == 0,
"Only clock-prescaler = <0> is supported when used with RTC");
#else
#define USE_RTC 0
#define GENERATOR_ADDR ((NRF_TIMER_Type *) DT_REG_ADDR(GENERATOR_NODE))
#endif
#define PWM_0_MAP_SIZE DT_INST_PROP_LEN(0, channel_gpios)
/* One compare channel is needed to set the PWM period, hence +1. */
#if ((PWM_0_MAP_SIZE + 1) > GENERATOR_CC_NUM)
#error "Invalid number of PWM channels configured."
#endif
/* When RTC is used, one more PPI task endpoint is required for clearing
* the counter, so when FORK feature is not available, one more PPI channel
* needs to be used.
*/
#if USE_RTC && !defined(PPI_FEATURE_FORKS_PRESENT)
#define PPI_PER_CH 3
#else
#define PPI_PER_CH 2
#endif
struct pwm_config {
union {
NRF_RTC_Type *rtc;
NRF_TIMER_Type *timer;
};
uint8_t psel_ch[PWM_0_MAP_SIZE];
uint8_t initially_inverted;
uint8_t map_size;
uint8_t prescaler;
};
struct pwm_data {
uint32_t period_cycles;
uint32_t pulse_cycles[PWM_0_MAP_SIZE];
uint8_t ppi_ch[PWM_0_MAP_SIZE][PPI_PER_CH];
uint8_t gpiote_ch[PWM_0_MAP_SIZE];
};
static inline NRF_RTC_Type *pwm_config_rtc(const struct pwm_config *config)
{
#if USE_RTC
return config->rtc;
#else
return NULL;
#endif
}
static inline NRF_TIMER_Type *pwm_config_timer(const struct pwm_config *config)
{
#if !USE_RTC
return config->timer;
#else
return NULL;
#endif
}
static uint32_t pwm_period_check(struct pwm_data *data, uint8_t map_size,
uint32_t channel, uint32_t period_cycles,
uint32_t pulse_cycles)
{
uint8_t i;
/* allow 0% and 100% duty cycle, as it does not use PWM. */
if ((pulse_cycles == 0U) || (pulse_cycles == period_cycles)) {
return 0;
}
/* fail if requested period does not match already running period */
for (i = 0U; i < map_size; i++) {
if ((i != channel) &&
(data->pulse_cycles[i] != 0U) &&
(period_cycles != data->period_cycles)) {
return -EINVAL;
}
}
return 0;
}
static int pwm_nrf5_sw_set_cycles(const struct device *dev, uint32_t channel,
uint32_t period_cycles, uint32_t pulse_cycles,
pwm_flags_t flags)
{
const struct pwm_config *config = dev->config;
NRF_TIMER_Type *timer = pwm_config_timer(config);
NRF_RTC_Type *rtc = pwm_config_rtc(config);
struct pwm_data *data = dev->data;
uint32_t ppi_mask;
uint8_t active_level;
uint8_t psel_ch;
uint8_t gpiote_ch;
const uint8_t *ppi_chs;
int ret;
if (channel >= config->map_size) {
LOG_ERR("Invalid channel: %u.", channel);
return -EINVAL;
}
/* check if requested period is allowed while other channels are
* active.
*/
ret = pwm_period_check(data, config->map_size, channel, period_cycles,
pulse_cycles);
if (ret) {
LOG_ERR("Incompatible period");
return ret;
}
if (USE_RTC) {
/* pulse_cycles - 1 is written to 24-bit CC */
if (period_cycles > BIT_MASK(24) + 1) {
LOG_ERR("Too long period (%u)!", period_cycles);
return -EINVAL;
}
} else {
/* TODO: if the assigned NRF_TIMER supports higher bit
* resolution, use that info in config struct.
*/
if (period_cycles > UINT16_MAX) {
LOG_ERR("Too long period (%u), adjust PWM prescaler!",
period_cycles);
return -EINVAL;
}
}
psel_ch = config->psel_ch[channel];
gpiote_ch = data->gpiote_ch[channel];
ppi_chs = data->ppi_ch[channel];
LOG_DBG("channel %u, period %u, pulse %u",
channel, period_cycles, pulse_cycles);
/* clear GPIOTE config */
NRF_GPIOTE->CONFIG[gpiote_ch] = 0;
/* clear PPI used */
ppi_mask = BIT(ppi_chs[0]) | BIT(ppi_chs[1]) |
(PPI_PER_CH > 2 ? BIT(ppi_chs[2]) : 0);
NRF_PPI->CHENCLR = ppi_mask;
active_level = (flags & PWM_POLARITY_INVERTED) ? 0 : 1;
/*
* If the duty cycle is 0% or 100%, there is no need to generate
* the PWM signal, just keep the output pin in inactive or active
* state, respectively.
*/
if (pulse_cycles == 0 || pulse_cycles == period_cycles) {
nrf_gpio_pin_write(psel_ch,
pulse_cycles == 0 ? !active_level
: active_level);
/* No PWM generation for this channel. */
data->pulse_cycles[channel] = 0U;
/* Check if PWM signal is generated on any channel. */
for (uint8_t i = 0; i < config->map_size; i++) {
if (data->pulse_cycles[i]) {
return 0;
}
}
/* No PWM generation needed, stop the timer. */
if (USE_RTC) {
rtc->TASKS_STOP = 1;
} else {
timer->TASKS_STOP = 1;
}
return 0;
}
/* configure RTC / TIMER */
if (USE_RTC) {
rtc->EVENTS_COMPARE[1 + channel] = 0;
rtc->EVENTS_COMPARE[0] = 0;
/*
* '- 1' adjusts pulse and period cycles to the fact that CLEAR
* task event is generated always one LFCLK cycle after period
* COMPARE value is reached.
*/
rtc->CC[1 + channel] = pulse_cycles - 1;
rtc->CC[0] = period_cycles - 1;
rtc->TASKS_CLEAR = 1;
} else {
timer->EVENTS_COMPARE[1 + channel] = 0;
timer->EVENTS_COMPARE[0] = 0;
timer->CC[1 + channel] = pulse_cycles;
timer->CC[0] = period_cycles;
timer->TASKS_CLEAR = 1;
}
/* Configure GPIOTE - toggle task with proper initial output value. */
NRF_GPIOTE->CONFIG[gpiote_ch] =
(GPIOTE_CONFIG_MODE_Task << GPIOTE_CONFIG_MODE_Pos) |
((uint32_t)psel_ch << 8) |
(GPIOTE_CONFIG_POLARITY_Toggle << GPIOTE_CONFIG_POLARITY_Pos) |
((uint32_t)active_level << GPIOTE_CONFIG_OUTINIT_Pos);
/* setup PPI */
if (USE_RTC) {
NRF_PPI->CH[ppi_chs[0]].EEP =
(uint32_t) &rtc->EVENTS_COMPARE[1 + channel];
NRF_PPI->CH[ppi_chs[0]].TEP =
(uint32_t) &NRF_GPIOTE->TASKS_OUT[gpiote_ch];
NRF_PPI->CH[ppi_chs[1]].EEP =
(uint32_t) &rtc->EVENTS_COMPARE[0];
NRF_PPI->CH[ppi_chs[1]].TEP =
(uint32_t) &NRF_GPIOTE->TASKS_OUT[gpiote_ch];
#if defined(PPI_FEATURE_FORKS_PRESENT)
NRF_PPI->FORK[ppi_chs[1]].TEP =
(uint32_t) &rtc->TASKS_CLEAR;
#else
NRF_PPI->CH[ppi_chs[2]].EEP =
(uint32_t) &rtc->EVENTS_COMPARE[0];
NRF_PPI->CH[ppi_chs[2]].TEP =
(uint32_t) &rtc->TASKS_CLEAR;
#endif
} else {
NRF_PPI->CH[ppi_chs[0]].EEP =
(uint32_t) &timer->EVENTS_COMPARE[1 + channel];
NRF_PPI->CH[ppi_chs[0]].TEP =
(uint32_t) &NRF_GPIOTE->TASKS_OUT[gpiote_ch];
NRF_PPI->CH[ppi_chs[1]].EEP =
(uint32_t) &timer->EVENTS_COMPARE[0];
NRF_PPI->CH[ppi_chs[1]].TEP =
(uint32_t) &NRF_GPIOTE->TASKS_OUT[gpiote_ch];
}
NRF_PPI->CHENSET = ppi_mask;
/* start timer, hence PWM */
if (USE_RTC) {
rtc->TASKS_START = 1;
} else {
timer->TASKS_START = 1;
}
/* store the period and pulse cycles */
data->period_cycles = period_cycles;
data->pulse_cycles[channel] = pulse_cycles;
return 0;
}
static int pwm_nrf5_sw_get_cycles_per_sec(const struct device *dev,
uint32_t channel, uint64_t *cycles)
{
const struct pwm_config *config = dev->config;
if (USE_RTC) {
/*
* RTC frequency is derived from 32768Hz source without any
* prescaler
*/
*cycles = 32768UL;
} else {
/*
* HF timer frequency is derived from 16MHz source with a
* prescaler
*/
*cycles = 16000000UL / BIT(config->prescaler);
}
return 0;
}
static const struct pwm_driver_api pwm_nrf5_sw_drv_api_funcs = {
.set_cycles = pwm_nrf5_sw_set_cycles,
.get_cycles_per_sec = pwm_nrf5_sw_get_cycles_per_sec,
};
static int pwm_nrf5_sw_init(const struct device *dev)
{
const struct pwm_config *config = dev->config;
struct pwm_data *data = dev->data;
NRF_TIMER_Type *timer = pwm_config_timer(config);
NRF_RTC_Type *rtc = pwm_config_rtc(config);
for (uint32_t i = 0; i < config->map_size; i++) {
nrfx_err_t err;
/* Allocate resources. */
for (uint32_t j = 0; j < PPI_PER_CH; j++) {
err = nrfx_ppi_channel_alloc(&data->ppi_ch[i][j]);
if (err != NRFX_SUCCESS) {
/* Do not free allocated resource. It is a fatal condition,
* system requires reconfiguration.
*/
LOG_ERR("Failed to allocate PPI channel");
return -ENOMEM;
}
}
err = nrfx_gpiote_channel_alloc(&data->gpiote_ch[i]);
if (err != NRFX_SUCCESS) {
/* Do not free allocated resource. It is a fatal condition,
* system requires reconfiguration.
*/
LOG_ERR("Failed to allocate GPIOTE channel");
return -ENOMEM;
}
/* Set initial state of the output pins. */
nrf_gpio_pin_write(config->psel_ch[i],
(config->initially_inverted & BIT(i)) ? 1 : 0);
nrf_gpio_cfg_output(config->psel_ch[i]);
}
if (USE_RTC) {
/* setup RTC */
rtc->PRESCALER = 0;
rtc->EVTENSET = (RTC_EVTENSET_COMPARE0_Msk |
RTC_EVTENSET_COMPARE1_Msk |
RTC_EVTENSET_COMPARE2_Msk |
RTC_EVTENSET_COMPARE3_Msk);
} else {
/* setup HF timer */
timer->MODE = TIMER_MODE_MODE_Timer;
timer->PRESCALER = config->prescaler;
timer->BITMODE = TIMER_BITMODE_BITMODE_16Bit;
timer->SHORTS = TIMER_SHORTS_COMPARE0_CLEAR_Msk;
}
return 0;
}
#define PSEL_AND_COMMA(_node_id, _prop, _idx) \
NRF_DT_GPIOS_TO_PSEL_BY_IDX(_node_id, _prop, _idx),
#define ACTIVE_LOW_BITS(_node_id, _prop, _idx) \
((DT_GPIO_FLAGS_BY_IDX(_node_id, _prop, _idx) & GPIO_ACTIVE_LOW) \
? BIT(_idx) : 0) |
static const struct pwm_config pwm_nrf5_sw_0_config = {
COND_CODE_1(USE_RTC, (.rtc), (.timer)) = GENERATOR_ADDR,
.psel_ch = {
DT_INST_FOREACH_PROP_ELEM(0, channel_gpios, PSEL_AND_COMMA)
},
.initially_inverted =
DT_INST_FOREACH_PROP_ELEM(0, channel_gpios, ACTIVE_LOW_BITS) 0,
.map_size = PWM_0_MAP_SIZE,
.prescaler = DT_INST_PROP(0, clock_prescaler),
};
static struct pwm_data pwm_nrf5_sw_0_data;
DEVICE_DT_INST_DEFINE(0,
pwm_nrf5_sw_init,
NULL,
&pwm_nrf5_sw_0_data,
&pwm_nrf5_sw_0_config,
POST_KERNEL,
CONFIG_PWM_INIT_PRIORITY,
&pwm_nrf5_sw_drv_api_funcs);