zephyr/machine_pwm: Implement PWM support.

Implement PWM support using standard zephyr APIs, exposed as the standard
MicroPython `machine.PWM` class.

Signed-off-by: Ayush Singh <[email protected]>

Author: Ayush1325

ports/zephyr/README.md

@@ -19,6 +19,7 @@ Features supported at this time:
 * `machine.Pin` class for GPIO control, with IRQ support.
 * `machine.I2C` class for I2C control.
 * `machine.SPI` class for SPI control.
+* `machine.PWM` class for PWM control
 * `socket` module for networking (IPv4/IPv6).
 * "Frozen modules" support to allow to bundle Python modules together
   with firmware. Including complete applications, including with

ports/zephyr/machine_pwm.c

@@ -0,0 +1,205 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2024 Ayush Singh <[email protected]>
+ *
+ * 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 "extmod/modmachine.h"
+#include "py/runtime.h"
+#include "stdint.h"
+#include "zephyr/drivers/pwm.h"
+#include "zephyr_device.h"
+
+#define VALUE_NOT_SET (-1)
+
+typedef struct _machine_pwm_obj_t {
+    mp_obj_base_t base;
+    const struct device *pwm;
+    uint32_t channel;
+    int32_t freq;
+    int32_t duty_u16;
+    int32_t duty_ns;
+    pwm_flags_t flags;
+} machine_pwm_obj_t;
+
+static void configure_pwm(machine_pwm_obj_t *self) {
+    const uint32_t period = NSEC_PER_SEC / self->freq;
+
+    if ((self->duty_u16 == VALUE_NOT_SET && self->duty_ns == VALUE_NOT_SET) ||
+        self->freq == VALUE_NOT_SET) {
+        mp_raise_ValueError(MP_ERROR_TEXT("Frequency and duty values must be set"));
+    }
+
+    if (self->duty_ns == VALUE_NOT_SET) {
+        self->duty_ns = (self->duty_u16 * period) / UINT16_MAX;
+    }
+
+    if (self->duty_ns < 0) {
+        self->duty_ns = 0;
+    } else if (self->duty_ns > period) {
+        self->duty_ns = period;
+    }
+
+    pwm_set(self->pwm, self->channel, period, self->duty_ns, self->flags);
+}
+
+/******************************************************************************/
+// MicroPython bindings for PWM
+
+static void mp_machine_pwm_print(const mp_print_t *print, mp_obj_t self_in,
+    mp_print_kind_t kind) {
+    machine_pwm_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_printf(print, "<PWM Controller %p channel=%d ", self->pwm, self->channel);
+
+    if (self->duty_ns != VALUE_NOT_SET) {
+        mp_printf(print, " duty_ns=%d", self->duty_ns);
+    } else {
+        mp_printf(print, " duty_u16=%d", self->duty_u16);
+    }
+
+    mp_printf(print, " freq=%d, flags=%u>", self->freq, self->flags);
+}
+
+// This called from pwm.init() method
+static void mp_machine_pwm_init_helper(machine_pwm_obj_t *self, size_t n_args,
+    const mp_obj_t *pos_args,
+    mp_map_t *kw_args) {
+
+    enum {
+        ARG_freq,
+        ARG_duty_u16,
+        ARG_duty_ns,
+        ARG_invert,
+    };
+    static const mp_arg_t allowed_args[] = {
+        {MP_QSTR_freq, MP_ARG_INT, {.u_int = VALUE_NOT_SET}},
+        {MP_QSTR_duty_u16, MP_ARG_INT, {.u_int = VALUE_NOT_SET}},
+        {MP_QSTR_duty_ns, MP_ARG_INT, {.u_int = VALUE_NOT_SET}},
+        {MP_QSTR_invert, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1}},
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args),
+        allowed_args, args);
+
+    // Maybe change PWM timer
+    if (args[ARG_freq].u_int > 0) {
+        self->freq = args[ARG_freq].u_int;
+    }
+
+    // Set duty_u16 cycle?
+    int32_t duty = args[ARG_duty_u16].u_int;
+    if (duty >= 0) {
+        self->duty_u16 = duty;
+        self->duty_ns = VALUE_NOT_SET;
+    }
+    // Set duty_ns value?
+    duty = args[ARG_duty_ns].u_int;
+    if (duty >= 0) {
+        self->duty_ns = duty;
+        self->duty_u16 = VALUE_NOT_SET;
+    }
+
+    self->flags = 0;
+    if (args[ARG_invert].u_int >= 0) {
+        self->flags |= PWM_POLARITY_INVERTED;
+    }
+
+    configure_pwm(self);
+}
+
+// PWM(pin-tuple, freq, [args])
+static mp_obj_t mp_machine_pwm_make_new(const mp_obj_type_t *type,
+    size_t n_args, size_t n_kw,
+    const mp_obj_t *args) {
+    mp_obj_t *items;
+    uint32_t wanted_chan;
+    const struct device *wanted_pwm;
+
+    // Check number of arguments
+    mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
+
+    // Get referred Pin object(s)
+    if (!mp_obj_is_type(args[0], &mp_type_tuple)) {
+        mp_raise_ValueError(
+            MP_ERROR_TEXT("Pin id must be tuple of (\"pwm_x\", channel#)"));
+    }
+
+    mp_obj_get_array_fixed_n(args[0], 2, &items);
+    wanted_pwm = zephyr_device_find(items[0]);
+    wanted_chan = mp_obj_get_int(items[1]);
+
+    machine_pwm_obj_t *pwm = mp_obj_malloc(machine_pwm_obj_t, &machine_pwm_type);
+    pwm->pwm = wanted_pwm;
+    pwm->channel = wanted_chan;
+    pwm->duty_ns = VALUE_NOT_SET;
+    pwm->duty_u16 = VALUE_NOT_SET;
+    pwm->freq = VALUE_NOT_SET;
+    pwm->flags = 0;
+
+    if (n_args > 1 || n_kw > 0) {
+        // pin mode given, so configure this GPIO
+        mp_map_t kw_args;
+        mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
+        mp_machine_pwm_init_helper(pwm, n_args - 1, args + 1, &kw_args);
+    }
+
+    return (mp_obj_t)pwm;
+}
+
+// This called from pwm.deinit() method
+static void mp_machine_pwm_deinit(machine_pwm_obj_t *self) {
+    self->duty_ns = 0;
+    self->duty_u16 = VALUE_NOT_SET;
+    configure_pwm(self);
+}
+
+static mp_obj_t mp_machine_pwm_freq_get(machine_pwm_obj_t *self) {
+    return MP_OBJ_NEW_SMALL_INT(self->freq);
+}
+
+static void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq) {
+    self->freq = freq;
+    configure_pwm(self);
+}
+
+static void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self,
+    mp_int_t duty_ns) {
+    self->duty_ns = duty_ns;
+    self->duty_u16 = VALUE_NOT_SET;
+    configure_pwm(self);
+}
+
+static mp_obj_t mp_machine_pwm_duty_get_ns(machine_pwm_obj_t *self) {
+    return MP_OBJ_NEW_SMALL_INT(self->duty_ns);
+}
+
+static mp_obj_t mp_machine_pwm_duty_get_u16(machine_pwm_obj_t *self) {
+    return MP_OBJ_NEW_SMALL_INT(self->duty_u16);
+}
+
+static void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self,
+    mp_int_t duty_u16) {
+    self->duty_ns = VALUE_NOT_SET;
+    self->duty_u16 = duty_u16;
+    configure_pwm(self);
+}

ports/zephyr/mpconfigport.h

@@ -72,6 +72,8 @@
 #define MICROPY_PY_MACHINE_WDT      (1)
 #define MICROPY_PY_MACHINE_WDT_INCLUDEFILE  "ports/zephyr/machine_wdt.c"
 #endif
+#define MICROPY_PY_MACHINE_PWM      (1)
+#define MICROPY_PY_MACHINE_PWM_INCLUDEFILE "ports/zephyr/machine_pwm.c"
 #define MICROPY_PY_STRUCT           (0)
 #ifdef CONFIG_NETWORKING
 // If we have networking, we likely want errno comfort