rp2/machine_uart: Add hardware flow control support.

Author: iabdalkader

ports/rp2/machine_uart.c

@@ -40,20 +40,29 @@
 #define DEFAULT_UART_STOP (1)
 #define DEFAULT_UART0_TX (0)
 #define DEFAULT_UART0_RX (1)
+#define DEFAULT_UART0_CTS (2)
+#define DEFAULT_UART0_RTS (3)
 #define DEFAULT_UART1_TX (4)
 #define DEFAULT_UART1_RX (5)
+#define DEFAULT_UART1_CTS (6)
+#define DEFAULT_UART1_RTS (7)
 #define DEFAULT_BUFFER_SIZE (256)
 #define MIN_BUFFER_SIZE  (32)
 #define MAX_BUFFER_SIZE  (32766)
 
 #define IS_VALID_PERIPH(uart, pin)  (((((pin) + 4) & 8) >> 3) == (uart))
 #define IS_VALID_TX(uart, pin)      (((pin) & 3) == 0 && IS_VALID_PERIPH(uart, pin))
 #define IS_VALID_RX(uart, pin)      (((pin) & 3) == 1 && IS_VALID_PERIPH(uart, pin))
+#define IS_VALID_CTS(uart, pin)     (((pin) & 3) == 2 && IS_VALID_PERIPH(uart, pin))
+#define IS_VALID_RTS(uart, pin)     (((pin) & 3) == 3 && IS_VALID_PERIPH(uart, pin))
 
 #define UART_INVERT_TX (1)
 #define UART_INVERT_RX (2)
 #define UART_INVERT_MASK (UART_INVERT_TX | UART_INVERT_RX)
 
+#define UART_HWCONTROL_CTS  (1)
+#define UART_HWCONTROL_RTS  (2)
+
 typedef struct _machine_uart_obj_t {
     mp_obj_base_t base;
     uart_inst_t *const uart;
@@ -64,9 +73,12 @@ typedef struct _machine_uart_obj_t {
     uint8_t stop;
     uint8_t tx;
     uint8_t rx;
+    uint8_t cts;
+    uint8_t rts;
     uint16_t timeout;       // timeout waiting for first char (in ms)
     uint16_t timeout_char;  // timeout waiting between chars (in ms)
     uint8_t invert;
+    uint8_t flow;
     ringbuf_t read_buffer;
     bool read_lock;
     ringbuf_t write_buffer;
@@ -75,9 +87,9 @@ typedef struct _machine_uart_obj_t {
 
 STATIC machine_uart_obj_t machine_uart_obj[] = {
     {{&machine_uart_type}, uart0, 0, 0, DEFAULT_UART_BITS, UART_PARITY_NONE, DEFAULT_UART_STOP,
-     DEFAULT_UART0_TX, DEFAULT_UART0_RX, 0, 0, 0, {NULL, 1, 0, 0}, 0, {NULL, 1, 0, 0}, 0},
+     DEFAULT_UART0_TX, DEFAULT_UART0_RX, DEFAULT_UART0_CTS, DEFAULT_UART0_RTS, 0, 0, 0, 0, {NULL, 1, 0, 0}, 0, {NULL, 1, 0, 0}, 0},
     {{&machine_uart_type}, uart1, 1, 0, DEFAULT_UART_BITS, UART_PARITY_NONE, DEFAULT_UART_STOP,
-     DEFAULT_UART1_TX, DEFAULT_UART1_RX, 0, 0, 0, {NULL, 1, 0, 0}, 0, {NULL, 1, 0, 0}, 0,},
+     DEFAULT_UART1_TX, DEFAULT_UART1_RX, DEFAULT_UART1_CTS, DEFAULT_UART1_RTS, 0, 0, 0, 0, {NULL, 1, 0, 0}, 0, {NULL, 1, 0, 0}, 0},
 };
 
 STATIC const char *_parity_name[] = {"None", "0", "1"};
@@ -140,8 +152,8 @@ STATIC void machine_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_pri
 }
 
 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 *all_args) {
-    enum { ARG_id, ARG_baudrate, ARG_bits, ARG_parity, ARG_stop, ARG_tx, ARG_rx,
-           ARG_timeout, ARG_timeout_char, ARG_invert, ARG_txbuf, ARG_rxbuf};
+    enum { ARG_id, ARG_baudrate, ARG_bits, ARG_parity, ARG_stop, ARG_tx, ARG_rx, ARG_cts, ARG_rts,
+           ARG_timeout, ARG_timeout_char, ARG_invert, ARG_flow, ARG_txbuf, ARG_rxbuf};
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
         { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = -1} },
@@ -150,9 +162,12 @@ STATIC mp_obj_t machine_uart_make_new(const mp_obj_type_t *type, size_t n_args,
         { MP_QSTR_stop, MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_tx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
         { MP_QSTR_rx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+        { MP_QSTR_cts, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+        { MP_QSTR_rts, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
         { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_timeout_char, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_invert, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
+        { MP_QSTR_flow, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_txbuf, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_rxbuf, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
     };
@@ -212,6 +227,22 @@ STATIC mp_obj_t machine_uart_make_new(const mp_obj_type_t *type, size_t n_args,
         self->rx = rx;
     }
 
+    // Set CTS/RTS pins if configured.
+    if (args[ARG_cts].u_obj != mp_const_none) {
+        int cts = mp_hal_get_pin_obj(args[ARG_cts].u_obj);
+        if (!IS_VALID_CTS(self->uart_id, cts)) {
+            mp_raise_ValueError(MP_ERROR_TEXT("bad CTS pin"));
+        }
+        self->cts = cts;
+    }
+    if (args[ARG_rts].u_obj != mp_const_none) {
+        int rts = mp_hal_get_pin_obj(args[ARG_rts].u_obj);
+        if (!IS_VALID_RTS(self->uart_id, rts)) {
+            mp_raise_ValueError(MP_ERROR_TEXT("bad RTS pin"));
+        }
+        self->rts = rts;
+    }
+
     // Set timeout if configured.
     if (args[ARG_timeout].u_int >= 0) {
         self->timeout = args[ARG_timeout].u_int;
@@ -230,6 +261,14 @@ STATIC mp_obj_t machine_uart_make_new(const mp_obj_type_t *type, size_t n_args,
         self->invert = args[ARG_invert].u_int;
     }
 
+    // Set hardware flow control if configured.
+    if (args[ARG_flow].u_int >= 0) {
+        if (args[ARG_flow].u_int & ~(UART_HWCONTROL_CTS | UART_HWCONTROL_RTS)) {
+            mp_raise_ValueError(MP_ERROR_TEXT("bad hardware flow control mask"));
+        }
+        self->flow = args[ARG_flow].u_int;
+    }
+
     self->read_lock = false;
 
     // Set the RX buffer size if configured.
@@ -278,6 +317,15 @@ STATIC mp_obj_t machine_uart_make_new(const mp_obj_type_t *type, size_t n_args,
             gpio_set_outover(self->tx, GPIO_OVERRIDE_INVERT);
         }
 
+        // Set hardware flow control if configured.
+        if (self->flow & UART_HWCONTROL_CTS) {
+            gpio_set_function(self->cts, GPIO_FUNC_UART);
+        }
+        if (self->flow & UART_HWCONTROL_RTS) {
+            gpio_set_function(self->rts, GPIO_FUNC_UART);
+        }
+        uart_set_hw_flow(self->uart, self->flow & UART_HWCONTROL_CTS, self->flow & UART_HWCONTROL_RTS);
+
         // Allocate the RX/TX buffers.
         ringbuf_alloc(&(self->read_buffer), rxbuf_len + 1);
         MP_STATE_PORT(rp2_uart_rx_buffer[uart_id]) = self->read_buffer.buf;
@@ -333,6 +381,9 @@ STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_INV_TX), MP_ROM_INT(UART_INVERT_TX) },
     { MP_ROM_QSTR(MP_QSTR_INV_RX), MP_ROM_INT(UART_INVERT_RX) },
 
+    { MP_ROM_QSTR(MP_QSTR_CTS), MP_ROM_INT(UART_HWCONTROL_CTS) },
+    { MP_ROM_QSTR(MP_QSTR_RTS), MP_ROM_INT(UART_HWCONTROL_RTS) },
+
 };
 STATIC MP_DEFINE_CONST_DICT(machine_uart_locals_dict, machine_uart_locals_dict_table);