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zephyr/drivers/pwm/pwm_nrfx.c

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