add circuitpython code

1 files changed, 307 insertions, 0 deletions

diff --git a/circuitpython/ports/raspberrypi/common-hal/pwmio/PWMOut.c b/circuitpython/ports/raspberrypi/common-hal/pwmio/PWMOut.c
new file mode 100644
index 0000000..3ef4fb5
--- /dev/null
+++ b/circuitpython/ports/raspberrypi/common-hal/pwmio/PWMOut.c
@@ -0,0 +1,307 @@
+/*
+ * 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 "shared/runtime/interrupt_char.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 AB_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 ab_channel) {
+    return 1 << (slice * AB_CHANNELS_PER_SLICE + ab_channel);
+}
+
+bool pwmio_claim_slice_ab_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_ab_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 ab_channel) {
+    never_reset_channel |= _mask(slice, ab_channel);
+}
+
+void pwmout_reset_ok(uint8_t slice, uint8_t ab_channel) {
+    never_reset_channel &= ~_mask(slice, ab_channel);
+}
+
+void common_hal_pwmio_pwmout_never_reset(pwmio_pwmout_obj_t *self) {
+    pwmout_never_reset(self->slice, self->ab_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->ab_channel);
+}
+
+void pwmout_reset(void) {
+    // Reset all slices
+    for (size_t slice = 0; slice < NUM_PWM_SLICES; slice++) {
+        bool reset = true;
+        for (size_t ab_channel = 0; ab_channel < AB_CHANNELS_PER_SLICE; ab_channel++) {
+            uint32_t channel_use_mask = _mask(slice, ab_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 ab_channel, bool variable_frequency, uint32_t frequency) {
+    uint32_t channel_use_mask = _mask(slice, ab_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;
+
+    claim_pin(pin);
+
+    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 ab_channel = pwm_gpio_to_channel(pin->number);
+
+    int r = pwmout_allocate(slice, ab_channel, variable_frequency, frequency);
+    if (r != PWMOUT_OK) {
+        return r;
+    }
+
+    self->slice = slice;
+    self->ab_channel = ab_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 ab_channel) {
+    uint32_t channel_mask = _mask(slice, ab_channel);
+    channel_use &= ~channel_mask;
+    never_reset_channel &= ~channel_mask;
+    uint32_t slice_mask = ((1 << AB_CHANNELS_PER_SLICE) - 1) << (slice * AB_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->ab_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->ab_channel, compare_count);
+    // Wait for wrap so that we know our new cc value has been applied. Clear
+    // the internal interrupt and then wait for it to be set. Worst case, we
+    // wait a full cycle.
+    pwm_hw->intr = 1 << self->slice;
+    while ((pwm_hw->en & (1 << self->slice)) != 0 &&
+           (pwm_hw->intr & (1 << self->slice)) == 0 &&
+           !mp_hal_is_interrupted()) {
+    }
+}
+
+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;
+}
+
+const mcu_pin_obj_t *common_hal_pwmio_pwmout_get_pin(pwmio_pwmout_obj_t *self) {
+    return self->pin;
+}