1. Set XXX_TAG static, remove extern XXX_TAG in uart.h/ledc.h/gpio.h
2. I removed uart_set/get_print_port() functions, these functions are not well tested, I removed them for now.
3. Modify some function names for uart_read/write_bytes
4. Modify uart_write_bytes and uart_write_bytes_with_break.
1. Use esp_log API for LEDC and GPIO code.
2. Modify some API return value.
3. Add ledc_set_pin() for LEDC
4. Modify typo in uart.h
Questions: In uart driver ISR handler, I used xxxFromISR , like xSemaphoreGiveFromISR, do those FromISR functions need to be put in IRAM?
1. configure LEDC timer saparately
2. add peripher_crtl.c/.h
To enable the peripheral modules, we have to set/clear the control register in dport_reg.h.
These bits are disabled by default and they are all in a same register, so we need to add a lock on that.
3. add include esp_err.h in gpio.h
