From ec24a150e02b7eff1271b59f0667cdb94a7aef62 Mon Sep 17 00:00:00 2001
From: "maple \"mavica\" syrup" <maple@maple.pet>
Date: Mon, 25 Mar 2024 18:32:17 -0300
Subject: [PATCH] extmod/machine_i2s: Prepare methods for PDM RX mode.

Signed-off-by: maple "mavica" syrup <maple@maple.pet>
---
 extmod/machine_i2s.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/extmod/machine_i2s.c b/extmod/machine_i2s.c
index 9c92eb4c92..22eb5af03d 100644
--- a/extmod/machine_i2s.c
+++ b/extmod/machine_i2s.c
@@ -344,7 +344,11 @@ static void copy_appbuf_to_ringbuf_non_blocking(machine_i2s_obj_t *self) {
 MP_NOINLINE static void machine_i2s_init_helper(machine_i2s_obj_t *self, size_t n_pos_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_sck,      MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_OBJ,   {.u_obj = MP_OBJ_NULL} },
+        #if MICROPY_PY_MACHINE_PDM
+        { MP_QSTR_ws,       MP_ARG_KW_ONLY | MP_ARG_OBJ,   {.u_obj = mp_const_none} },
+        #else
         { MP_QSTR_ws,       MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_OBJ,   {.u_obj = MP_OBJ_NULL} },
+        #endif
         { MP_QSTR_sd,       MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_OBJ,   {.u_obj = MP_OBJ_NULL} },
         #if MICROPY_PY_MACHINE_I2S_MCK
         { MP_QSTR_mck,      MP_ARG_KW_ONLY | MP_ARG_OBJ,   {.u_obj = mp_const_none} },
@@ -517,6 +521,9 @@ static const mp_rom_map_elem_t machine_i2s_locals_dict_table[] = {
     // Constants
     { MP_ROM_QSTR(MP_QSTR_RX),              MP_ROM_INT(MICROPY_PY_MACHINE_I2S_CONSTANT_RX) },
     { MP_ROM_QSTR(MP_QSTR_TX),              MP_ROM_INT(MICROPY_PY_MACHINE_I2S_CONSTANT_TX) },
+    #if MICROPY_PY_MACHINE_PDM
+    { MP_ROM_QSTR(MP_QSTR_PDM_RX),          MP_ROM_INT(MICROPY_PY_MACHINE_I2S_PDM_RX) },
+    #endif
     { MP_ROM_QSTR(MP_QSTR_STEREO),          MP_ROM_INT(STEREO) },
     { MP_ROM_QSTR(MP_QSTR_MONO),            MP_ROM_INT(MONO) },
 };
@@ -525,10 +532,18 @@ MP_DEFINE_CONST_DICT(machine_i2s_locals_dict, machine_i2s_locals_dict_table);
 static mp_uint_t machine_i2s_stream_read(mp_obj_t self_in, void *buf_in, mp_uint_t size, int *errcode) {
     machine_i2s_obj_t *self = MP_OBJ_TO_PTR(self_in);
 
+    #if MICROPY_PY_MACHINE_PDM
+    if ((self->mode != MICROPY_PY_MACHINE_I2S_CONSTANT_RX) &&
+        (self->mode != MICROPY_PY_MACHINE_I2S_PDM_RX)) {
+        *errcode = MP_EPERM;
+        return MP_STREAM_ERROR;
+    }
+    #else
     if (self->mode != MICROPY_PY_MACHINE_I2S_CONSTANT_RX) {
         *errcode = MP_EPERM;
         return MP_STREAM_ERROR;
     }
+    #endif
 
     uint8_t appbuf_sample_size_in_bytes = (self->bits / 8) * (self->format == STEREO ? 2: 1);
     if (size % appbuf_sample_size_in_bytes != 0) {
@@ -623,10 +638,18 @@ static mp_uint_t machine_i2s_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_
         ret = 0;
 
         if (flags & MP_STREAM_POLL_RD) {
+            #if MICROPY_PY_MACHINE_PDM
+            if ((self->mode != MICROPY_PY_MACHINE_I2S_CONSTANT_RX) &&
+                (self->mode != MICROPY_PY_MACHINE_I2S_PDM_RX)) {
+                *errcode = MP_EPERM;
+                return MP_STREAM_ERROR;
+            }
+            #else
             if (self->mode != MICROPY_PY_MACHINE_I2S_CONSTANT_RX) {
                 *errcode = MP_EPERM;
                 return MP_STREAM_ERROR;
             }
+            #endif
 
             #if MICROPY_PY_MACHINE_I2S_RING_BUF
             if (!ringbuf_is_empty(&self->ring_buffer)) {