Uart improvments (#1024)

* uart: Add support for specifying the number of bits and parity.

ESP8266SwSerial doesn't really check parity but just read the parity bit
and ignore it when receiving data.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: support begin and end methods.

A component may need to reset uart buffer/status by using begin() and
end() methods. This is useful for example when a component needs to be
sure it is not reading garbage from previously received data over uart.
For end() methods with software serial, disabling interrupt is
currently impossible because of a bug in esp8266 Core:
https://github.com/esp8266/Arduino/issues/6049

Signed-off-by: 0hax <0hax@protonmail.com>

* esphal: add support for detaching an interrupt.

That's needed when a component needs to enable/disable interrupt on a
gpio.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: rename CONF_NR_BITS to CONF_DATA_BITS_NUMBER.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: use static const uint32_t instead of #define.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: use an enum to handle parity.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: split between esp32 and esp8266.

Signed-off-by: 0hax <0hax@protonmail.com>

* uart: check_uart_settings for parity and number of data bits.

Signed-off-by: 0hax <0hax@protonmail.com>

* name param data_bits

* add new params to test

Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>

esphome/core/esphal.cpp

@@ -12,6 +12,7 @@ typedef struct {        // NOLINT
 
 void ICACHE_RAM_ATTR __attachInterruptArg(uint8_t pin, void (*)(void *), void *fp,  // NOLINT
                                           int mode);
+void ICACHE_RAM_ATTR __detachInterrupt(uint8_t pin);  // NOLINT
 };
 #endif
 
@@ -226,6 +227,15 @@ void ICACHE_RAM_ATTR interrupt_handler(void *arg) {
 }
 #endif
 
+void GPIOPin::detach_interrupt() const { this->detach_interrupt_(); }
+void GPIOPin::detach_interrupt_() const {
+#ifdef ARDUINO_ARCH_ESP8266
+  __detachInterrupt(get_pin());
+#endif
+#ifdef ARDUINO_ARCH_ESP32
+  detachInterrupt(get_pin());
+#endif
+}
 void GPIOPin::attach_interrupt_(void (*func)(void *), void *arg, int mode) const {
   if (this->inverted_) {
     if (mode == RISING) {