From 7a7ee16ccf51d4218c17628e745228316f0151f0 Mon Sep 17 00:00:00 2001
From: Jeremy Herbert <jeremy.006@gmail.com>
Date: Thu, 10 Oct 2019 05:11:01 -0700
Subject: [PATCH] esp32/machine_uart: Add ability to invert UART pins.

---
 ports/esp32/machine_uart.c | 47 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/ports/esp32/machine_uart.c b/ports/esp32/machine_uart.c
index 38cc1a8a9a..352ef32a78 100644
--- a/ports/esp32/machine_uart.c
+++ b/ports/esp32/machine_uart.c
@@ -50,6 +50,7 @@ typedef struct _machine_uart_obj_t {
     uint16_t rxbuf;
     uint16_t timeout;       // timeout waiting for first char (in ms)
     uint16_t timeout_char;  // timeout waiting between chars (in ms)
+    uint32_t invert;        // lines to invert
 } machine_uart_obj_t;
 
 STATIC const char *_parity_name[] = {"None", "1", "0"};
@@ -61,13 +62,42 @@ STATIC void machine_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_pri
     machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
     uint32_t baudrate;
     uart_get_baudrate(self->uart_num, &baudrate);
-    mp_printf(print, "UART(%u, baudrate=%u, bits=%u, parity=%s, stop=%u, tx=%d, rx=%d, rts=%d, cts=%d, txbuf=%u, rxbuf=%u, timeout=%u, timeout_char=%u)",
+    mp_printf(print, "UART(%u, baudrate=%u, bits=%u, parity=%s, stop=%u, tx=%d, rx=%d, rts=%d, cts=%d, txbuf=%u, rxbuf=%u, timeout=%u, timeout_char=%u",
         self->uart_num, baudrate, self->bits, _parity_name[self->parity],
         self->stop, self->tx, self->rx, self->rts, self->cts, self->txbuf, self->rxbuf, self->timeout, self->timeout_char);
+    if (self->invert) {
+        mp_printf(print, ", invert=");
+        uint32_t invert_mask = self->invert;
+        if (invert_mask & UART_INVERSE_TXD) {
+            mp_printf(print, "INV_TX");
+            invert_mask &= ~UART_INVERSE_TXD;
+            if (invert_mask) {
+                mp_printf(print, "|");
+            }
+        }
+        if (invert_mask & UART_INVERSE_RXD) {
+            mp_printf(print, "INV_RX");
+            invert_mask &= ~UART_INVERSE_RXD;
+            if (invert_mask) {
+                mp_printf(print, "|");
+            }
+        }
+        if (invert_mask & UART_INVERSE_RTS) {
+            mp_printf(print, "INV_RTS");
+            invert_mask &= ~UART_INVERSE_RTS;
+            if (invert_mask) {
+                mp_printf(print, "|");
+            }
+        }
+        if (invert_mask & UART_INVERSE_CTS) {
+            mp_printf(print, "INV_CTS");
+        }
+    }
+    mp_printf(print, ")");
 }
 
 STATIC void machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_baudrate, ARG_bits, ARG_parity, ARG_stop, ARG_tx, ARG_rx, ARG_rts, ARG_cts, ARG_txbuf, ARG_rxbuf, ARG_timeout, ARG_timeout_char };
+    enum { ARG_baudrate, ARG_bits, ARG_parity, ARG_stop, ARG_tx, ARG_rx, ARG_rts, ARG_cts, ARG_txbuf, ARG_rxbuf, ARG_timeout, ARG_timeout_char, ARG_invert };
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = 0} },
         { MP_QSTR_bits, MP_ARG_INT, {.u_int = 0} },
@@ -81,6 +111,7 @@ STATIC void machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args, co
         { MP_QSTR_rxbuf, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
         { MP_QSTR_timeout_char, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_invert, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
     };
     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);
@@ -205,6 +236,13 @@ STATIC void machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args, co
     if (self->timeout_char < min_timeout_char) {
         self->timeout_char = min_timeout_char;
     }
+
+    // set line inversion
+    if (args[ARG_invert].u_int & ~UART_LINE_INV_MASK) {
+        mp_raise_ValueError("invalid inversion mask");
+    }
+    self->invert = args[ARG_invert].u_int;
+    uart_set_line_inverse(self->uart_num, self->invert);
 }
 
 STATIC mp_obj_t machine_uart_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
@@ -341,6 +379,11 @@ STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
     { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
     { MP_ROM_QSTR(MP_QSTR_sendbreak), MP_ROM_PTR(&machine_uart_sendbreak_obj) },
+
+    { MP_ROM_QSTR(MP_QSTR_INV_TX), MP_ROM_INT(UART_INVERSE_TXD) },
+    { MP_ROM_QSTR(MP_QSTR_INV_RX), MP_ROM_INT(UART_INVERSE_RXD) },
+    { MP_ROM_QSTR(MP_QSTR_INV_RTS), MP_ROM_INT(UART_INVERSE_RTS) },
+    { MP_ROM_QSTR(MP_QSTR_INV_CTS), MP_ROM_INT(UART_INVERSE_CTS) },
 };
 
 STATIC MP_DEFINE_CONST_DICT(machine_uart_locals_dict, machine_uart_locals_dict_table);