circuitpython/ports/raspberrypi/common-hal/pwmio/PWMOut.c

293 lines
10 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2021 Scott Shawcroft for Adafruit Industries
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdint.h>
#include "py/runtime.h"
#include "common-hal/pwmio/PWMOut.h"
#include "shared-bindings/pwmio/PWMOut.h"
#include "shared-bindings/microcontroller/Processor.h"
#include "supervisor/shared/translate.h"
#include "src/rp2040/hardware_regs/include/hardware/platform_defs.h"
#include "src/rp2_common/hardware_clocks/include/hardware/clocks.h"
#include "src/rp2_common/hardware_gpio/include/hardware/gpio.h"
#include "src/rp2_common/hardware_pwm/include/hardware/pwm.h"
uint32_t target_slice_frequencies[NUM_PWM_SLICES];
uint32_t slice_variable_frequency;
#define CHANNELS_PER_SLICE 2
static uint32_t channel_use;
static uint32_t never_reset_channel;
// Per the RP2040 datasheet:
//
// "A CC value of 0 will produce a 0% output, i.e. the output signal
// is always low. A CC value of TOP + 1 (i.e. equal to the period, in
// non-phase-correct mode) will produce a 100% output. For example, if
// TOP is programmed to 254, the counter will have a period of 255
// cycles, and CC values in the range of 0 to 255 inclusive will
// produce duty cycles in the range 0% to 100% inclusive."
//
// So 65534 should be the maximum top value, and we'll set CC to be TOP+1 as appropriate.
#define MAX_TOP 65534
static uint32_t _mask(uint8_t slice, uint8_t channel) {
return 1 << (slice * CHANNELS_PER_SLICE + channel);
}
bool pwmio_claim_slice_channels(uint8_t slice) {
uint32_t channel_use_mask_a = _mask(slice, 0);
uint32_t channel_use_mask_b = _mask(slice, 1);
if ((channel_use & channel_use_mask_a) != 0) {
return false;
}
if ((channel_use & channel_use_mask_b) != 0) {
return false;
}
channel_use |= channel_use_mask_a;
channel_use |= channel_use_mask_b;
return true;
}
void pwmio_release_slice_channels(uint8_t slice) {
uint32_t channel_mask = _mask(slice, 0);
channel_use &= ~channel_mask;
channel_mask = _mask(slice, 1);
channel_use &= ~channel_mask;
}
void pwmout_never_reset(uint8_t slice, uint8_t channel) {
never_reset_channel |= _mask(slice, channel);
}
void pwmout_reset_ok(uint8_t slice, uint8_t channel) {
never_reset_channel &= ~_mask(slice, channel);
}
void common_hal_pwmio_pwmout_never_reset(pwmio_pwmout_obj_t *self) {
pwmout_never_reset(self->slice, self->channel);
never_reset_pin_number(self->pin->number);
}
void common_hal_pwmio_pwmout_reset_ok(pwmio_pwmout_obj_t *self) {
pwmout_reset_ok(self->slice, self->channel);
}
void pwmout_reset(void) {
// Reset all slices
for (size_t slice = 0; slice < NUM_PWM_SLICES; slice++) {
bool reset = true;
for (size_t channel = 0; channel < CHANNELS_PER_SLICE; channel++) {
uint32_t channel_use_mask = _mask(slice, channel);
if ((never_reset_channel & channel_use_mask) != 0) {
reset = false;
continue;
}
channel_use &= ~channel_use_mask;
}
if (!reset) {
continue;
}
pwm_set_enabled(slice, false);
target_slice_frequencies[slice] = 0;
slice_variable_frequency &= ~(1 << slice);
}
}
pwmout_result_t pwmout_allocate(uint8_t slice, uint8_t channel, bool variable_frequency, uint32_t frequency) {
uint32_t channel_use_mask = _mask(slice, channel);
// Check the channel first.
if ((channel_use & channel_use_mask) != 0) {
return PWMOUT_ALL_TIMERS_ON_PIN_IN_USE;
}
// Now check if the slice is in use and if we can share with it.
if (target_slice_frequencies[slice] > 0) {
// If we want to change frequency then we can't share.
if (variable_frequency) {
return PWMOUT_ALL_TIMERS_ON_PIN_IN_USE;
}
// If the other user wants a variable frequency then we can't share either.
if ((slice_variable_frequency & (1 << slice)) != 0) {
return PWMOUT_ALL_TIMERS_ON_PIN_IN_USE;
}
// If we're both fixed frequency but we don't match target frequencies then we can't share.
if (target_slice_frequencies[slice] != frequency) {
return PWMOUT_ALL_TIMERS_ON_PIN_IN_USE;
}
}
channel_use |= channel_use_mask;
if (variable_frequency) {
slice_variable_frequency |= 1 << slice;
}
return PWMOUT_OK;
}
pwmout_result_t common_hal_pwmio_pwmout_construct(pwmio_pwmout_obj_t *self,
const mcu_pin_obj_t *pin,
uint16_t duty,
uint32_t frequency,
bool variable_frequency) {
self->pin = pin;
self->variable_frequency = variable_frequency;
self->duty_cycle = duty;
if (frequency == 0 || frequency > (common_hal_mcu_processor_get_frequency() / 2)) {
return PWMOUT_INVALID_FREQUENCY;
}
uint8_t slice = pwm_gpio_to_slice_num(pin->number);
uint8_t channel = pwm_gpio_to_channel(pin->number);
int r = pwmout_allocate(slice, channel, variable_frequency, frequency);
if (r != PWMOUT_OK) {
return r;
}
self->slice = slice;
self->channel = channel;
if (target_slice_frequencies[slice] != frequency) {
// Reset the counter and compare values.
pwm_hw->slice[slice].ctr = PWM_CH0_CTR_RESET;
common_hal_pwmio_pwmout_set_duty_cycle(self, duty);
common_hal_pwmio_pwmout_set_frequency(self, frequency);
pwm_set_enabled(slice, true);
} else {
common_hal_pwmio_pwmout_set_frequency(self, frequency);
common_hal_pwmio_pwmout_set_duty_cycle(self, duty);
}
// Connect to the pad last to avoid any glitches from changing settings.
gpio_set_function(pin->number, GPIO_FUNC_PWM);
return PWMOUT_OK;
}
bool common_hal_pwmio_pwmout_deinited(pwmio_pwmout_obj_t *self) {
return self->pin == NULL;
}
void pwmout_free(uint8_t slice, uint8_t channel) {
uint32_t channel_mask = _mask(slice, channel);
channel_use &= ~channel_mask;
never_reset_channel &= ~channel_mask;
uint32_t slice_mask = ((1 << CHANNELS_PER_SLICE) - 1) << (slice * CHANNELS_PER_SLICE);
if ((channel_use & slice_mask) == 0) {
target_slice_frequencies[slice] = 0;
slice_variable_frequency &= ~(1 << slice);
pwm_set_enabled(slice, false);
}
}
void common_hal_pwmio_pwmout_deinit(pwmio_pwmout_obj_t *self) {
if (common_hal_pwmio_pwmout_deinited(self)) {
return;
}
pwmout_free(self->slice, self->channel);
reset_pin_number(self->pin->number);
self->pin = NULL;
}
extern void common_hal_pwmio_pwmout_set_duty_cycle(pwmio_pwmout_obj_t *self, uint16_t duty) {
self->duty_cycle = duty;
// Do arithmetic in 32 bits to prevent overflow.
uint16_t compare_count;
if (duty == 65535) {
// Ensure that 100% duty cycle is 100% full on and not rounded down,
// but do MIN() to keep value in range, just in case.
compare_count = MIN(UINT16_MAX, (uint32_t)self->top + 1);
} else {
compare_count = ((uint32_t)duty * self->top + MAX_TOP / 2) / MAX_TOP;
}
// compare_count is the CC register value, which should be TOP+1 for 100% duty cycle.
pwm_set_chan_level(self->slice, self->channel, compare_count);
}
uint16_t common_hal_pwmio_pwmout_get_duty_cycle(pwmio_pwmout_obj_t *self) {
return self->duty_cycle;
}
void pwmio_pwmout_set_top(pwmio_pwmout_obj_t *self, uint16_t top) {
self->actual_frequency = common_hal_mcu_processor_get_frequency() / top;
self->top = top;
pwm_set_clkdiv_int_frac(self->slice, 1, 0);
pwm_set_wrap(self->slice, self->top);
}
void common_hal_pwmio_pwmout_set_frequency(pwmio_pwmout_obj_t *self, uint32_t frequency) {
if (frequency == 0 || frequency > (common_hal_mcu_processor_get_frequency() / 2)) {
mp_raise_ValueError(translate("Invalid PWM frequency"));
}
target_slice_frequencies[self->slice] = frequency;
// For low frequencies use the divider to give us full resolution duty_cycle.
if (frequency <= (common_hal_mcu_processor_get_frequency() / (1 << 16))) {
// Compute the divisor. It's an 8 bit integer and 4 bit fraction. Therefore,
// we compute everything * 16 for the fractional part.
// This is 1 << 12 because 4 bits are the * 16.
uint64_t frequency16 = ((uint64_t)clock_get_hz(clk_sys)) / (1 << 12);
uint64_t div16 = frequency16 / frequency;
// Round the divisor to try and get closest to the target frequency. We could
// also always round up and use TOP to get us closer. We may not need that though.
if (frequency16 % frequency >= frequency / 2) {
div16 += 1;
}
if (div16 >= (1 << 12)) {
div16 = (1 << 12) - 1;
}
self->actual_frequency = (frequency16 + (div16 / 2)) / div16;
self->top = MAX_TOP;
pwm_set_clkdiv_int_frac(self->slice, div16 / 16, div16 % 16);
pwm_set_wrap(self->slice, self->top);
} else {
uint32_t top = common_hal_mcu_processor_get_frequency() / frequency;
self->actual_frequency = common_hal_mcu_processor_get_frequency() / top;
self->top = MIN(MAX_TOP, top);
pwm_set_clkdiv_int_frac(self->slice, 1, 0);
// Set TOP register. For 100% duty cycle, CC must be set to TOP+1.
pwm_set_wrap(self->slice, self->top);
}
common_hal_pwmio_pwmout_set_duty_cycle(self, self->duty_cycle);
}
uint32_t common_hal_pwmio_pwmout_get_frequency(pwmio_pwmout_obj_t *self) {
return self->actual_frequency;
}
bool common_hal_pwmio_pwmout_get_variable_frequency(pwmio_pwmout_obj_t *self) {
return self->variable_frequency;
}