rp2/machine_pwm: Enable keyword args in constructor and add init method.

This adds support for freq/duty_u16/duty_ns keyword arguments in the PWM
constructor, and adds the PWM.init() method.  Using init() without
arguments enables a previously deinit-ed PWM again.

Further changes in this commit:
- Do not start PWM output if only duty was set.
- Stop all PWM slices on soft-reset.
- Fix a bug when changing the freq on a channel pair with duty_ns set.

4 files changed, 80 insertions, 21 deletions

diff --git a/ports/rp2/machine_pwm.c b/ports/rp2/machine_pwm.c
index 0c840eca9..5a0c4751e 100644
--- a/ports/rp2/machine_pwm.c
+++ b/ports/rp2/machine_pwm.c
@@ -39,34 +39,37 @@ typedef struct _machine_pwm_obj_t {
     uint8_t slice;
     uint8_t channel;
     uint8_t duty_type;
+    bool freq_set;
     mp_int_t duty;
 } machine_pwm_obj_t;
 
 enum {
+    VALUE_NOT_SET = -1,
     DUTY_NOT_SET = 0,
     DUTY_U16,
     DUTY_NS
 };
 
 STATIC machine_pwm_obj_t machine_pwm_obj[] = {
-    {{&machine_pwm_type}, 0, PWM_CHAN_A, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 0, PWM_CHAN_B, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 1, PWM_CHAN_A, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 1, PWM_CHAN_B, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 2, PWM_CHAN_A, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 2, PWM_CHAN_B, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 3, PWM_CHAN_A, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 3, PWM_CHAN_B, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 4, PWM_CHAN_A, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 4, PWM_CHAN_B, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 5, PWM_CHAN_A, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 5, PWM_CHAN_B, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 6, PWM_CHAN_A, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 6, PWM_CHAN_B, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 7, PWM_CHAN_A, DUTY_NOT_SET, 0},
-    {{&machine_pwm_type}, 7, PWM_CHAN_B, DUTY_NOT_SET, 0},
+    {{&machine_pwm_type}, 0, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 0, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 1, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 1, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 2, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 2, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 3, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 3, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 4, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 4, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 5, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 5, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 6, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 6, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 7, PWM_CHAN_A, DUTY_NOT_SET, 0, 0 },
+    {{&machine_pwm_type}, 7, PWM_CHAN_B, DUTY_NOT_SET, 0, 0 },
 };
 
+STATIC void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq);
 STATIC void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u16);
 STATIC void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns);
 
@@ -75,10 +78,46 @@ STATIC void mp_machine_pwm_print(const mp_print_t *print, mp_obj_t self_in, mp_p
     mp_printf(print, "<PWM slice=%u channel=%u>", self->slice, self->channel);
 }
 
-// PWM(pin)
+void machine_pwm_start(machine_pwm_obj_t *self) {
+    // Start the PWM if properly set.
+    if (self->freq_set && self->duty_type != DUTY_NOT_SET) {
+        pwm_set_enabled(self->slice, true);
+    }
+}
+
+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 };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_freq,     MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
+        { MP_QSTR_duty_u16, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
+        { MP_QSTR_duty_ns,  MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
+    };
+
+    // Parse the arguments.
+    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);
+
+    if ((n_args + kw_args->used) > 0) {
+        if (args[ARG_freq].u_int != VALUE_NOT_SET) {
+            mp_machine_pwm_freq_set(self, args[ARG_freq].u_int);
+        }
+        if (args[ARG_duty_u16].u_int != VALUE_NOT_SET) {
+            mp_machine_pwm_duty_set_u16(self, args[ARG_duty_u16].u_int);
+        }
+        if (args[ARG_duty_ns].u_int != VALUE_NOT_SET) {
+            mp_machine_pwm_duty_set_ns(self, args[ARG_duty_ns].u_int);
+        }
+    } else {
+        machine_pwm_start(self);
+    }
+}
+
+// PWM(pin [, 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 *all_args) {
     // Check number of arguments
-    mp_arg_check_num(n_args, n_kw, 1, 1, false);
+    mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
 
     // Get GPIO to connect to PWM.
     uint32_t gpio = mp_hal_get_pin_obj(all_args[0]);
@@ -87,16 +126,28 @@ STATIC mp_obj_t mp_machine_pwm_make_new(const mp_obj_type_t *type, size_t n_args
     uint slice = pwm_gpio_to_slice_num(gpio);
     uint8_t channel = pwm_gpio_to_channel(gpio);
     machine_pwm_obj_t *self = &machine_pwm_obj[slice * 2 + channel];
+    self->freq_set = false;
     self->duty_type = DUTY_NOT_SET;
 
     // Select PWM function for given GPIO.
     gpio_set_function(gpio, GPIO_FUNC_PWM);
 
+    // Process the remaining parameters.
+    mp_map_t kw_args;
+    mp_map_init_fixed_table(&kw_args, n_kw, all_args + n_args);
+    mp_machine_pwm_init_helper(self, n_args - 1, all_args + 1, &kw_args);
+
     return MP_OBJ_FROM_PTR(self);
 }
 
+// Stop all active slices.
+void machine_pwm_deinit_all(void) {
+    for (int i = 0; i < 8; i++) {
+        pwm_set_enabled(machine_pwm_obj[i].slice, false);
+    }
+}
+
 STATIC void mp_machine_pwm_deinit(machine_pwm_obj_t *self) {
-    self->duty_type = DUTY_NOT_SET;
     pwm_set_enabled(self->slice, false);
 }
 
@@ -165,11 +216,16 @@ STATIC void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq) {
     }
     pwm_hw->slice[self->slice].div = div16;
     pwm_hw->slice[self->slice].top = top;
+    self->freq_set = true;
     if (self->duty_type == DUTY_U16) {
         mp_machine_pwm_duty_set_u16(self, self->duty);
     } else if (self->duty_type == DUTY_NS) {
         mp_machine_pwm_duty_set_ns(self, self->duty);
     }
+    machine_pwm_obj_t *other = self->channel == PWM_CHAN_A ? self + 1 : self - 1;
+    if (other->duty_type == DUTY_NS) {
+        mp_machine_pwm_duty_set_ns(other, other->duty);
+    }
 }
 
 STATIC mp_obj_t mp_machine_pwm_duty_get_u16(machine_pwm_obj_t *self) {
@@ -188,9 +244,9 @@ STATIC void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u
     // Use rounding here to set it as accurately as possible.
     uint32_t cc = (duty_u16 * (top + 1) + 65535 / 2) / 65535;
     pwm_set_chan_level(self->slice, self->channel, cc);
-    pwm_set_enabled(self->slice, true);
     self->duty = duty_u16;
     self->duty_type = DUTY_U16;
+    machine_pwm_start(self);
 }
 
 STATIC mp_obj_t mp_machine_pwm_duty_get_ns(machine_pwm_obj_t *self) {
@@ -207,7 +263,7 @@ STATIC void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns
         mp_raise_ValueError(MP_ERROR_TEXT("duty larger than period"));
     }
     pwm_set_chan_level(self->slice, self->channel, cc);
-    pwm_set_enabled(self->slice, true);
     self->duty = duty_ns;
     self->duty_type = DUTY_NS;
+    machine_pwm_start(self);
 }
diff --git a/ports/rp2/main.c b/ports/rp2/main.c
index 059449695..0ecc09b34 100644
--- a/ports/rp2/main.c
+++ b/ports/rp2/main.c
@@ -206,6 +206,7 @@ int main(int argc, char **argv) {
         #if MICROPY_PY_BLUETOOTH
         mp_bluetooth_deinit();
         #endif
+        machine_pwm_deinit_all();
         machine_pin_deinit();
         #if MICROPY_PY_THREAD
         mp_thread_deinit();
diff --git a/ports/rp2/modmachine.h b/ports/rp2/modmachine.h
index 6ea4def91..45ccd49e8 100644
--- a/ports/rp2/modmachine.h
+++ b/ports/rp2/modmachine.h
@@ -16,6 +16,7 @@ extern const mp_obj_type_t machine_wdt_type;
 void machine_pin_init(void);
 void machine_pin_deinit(void);
 void machine_i2s_init0(void);
+void machine_pwm_deinit_all(void);
 
 struct _machine_spi_obj_t *spi_from_mp_obj(mp_obj_t o);
 NORETURN mp_obj_t machine_bootloader(size_t n_args, const mp_obj_t *args);
diff --git a/ports/rp2/mpconfigport.h b/ports/rp2/mpconfigport.h
index 17586e509..653b51091 100644
--- a/ports/rp2/mpconfigport.h
+++ b/ports/rp2/mpconfigport.h
@@ -114,6 +114,7 @@
 #define MICROPY_PY_MACHINE_BITSTREAM            (1)
 #define MICROPY_PY_MACHINE_PULSE                (1)
 #define MICROPY_PY_MACHINE_PWM                  (1)
+#define MICROPY_PY_MACHINE_PWM_INIT             (1)
 #define MICROPY_PY_MACHINE_PWM_DUTY_U16_NS      (1)
 #define MICROPY_PY_MACHINE_PWM_INCLUDEFILE      "ports/rp2/machine_pwm.c"
 #define MICROPY_PY_MACHINE_I2C                  (1)