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/* Copyright 2017 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef __CROS_EC_CHIP_G_UART_BITBANG_H
#define __CROS_EC_CHIP_G_UART_BITBANG_H
/* UART Bit Banging */
#include "common.h"
#include "gpio.h"
/* These are functions that we'll have to replace. */
struct uartn_function_ptrs {
int (*_rx_available)(int uart);
void (*_write_char)(int uart, char c);
int (*_read_char)(int uart);
};
/*
* And these are the function definitions. The functions live in
* chip/g/uartn.c.
*/
extern int _uartn_rx_available(int uart);
extern void _uartn_write_char(int uart, char c);
extern int _uartn_read_char(int uart);
extern int _uart_bitbang_rx_available(int uart);
extern void _uart_bitbang_write_char(int uart, char c);
extern int _uart_bitbang_read_char(int uart);
extern struct uartn_function_ptrs uartn_funcs[];
struct uart_bitbang_properties {
enum gpio_signal tx_gpio;
enum gpio_signal rx_gpio;
uint32_t tx_pinmux_reg;
uint32_t tx_pinmux_regval;
uint32_t rx_pinmux_reg;
uint32_t rx_pinmux_regval;
int baud_rate;
uint8_t uart;
struct {
unsigned int head : 3;
unsigned int tail : 3;
unsigned int parity : 2;
} htp __packed;
};
/* In order to bitbang a UART, a board must define a bitbang_config. */
extern struct uart_bitbang_properties bitbang_config;
/**
* Configure bit banging mode for a UART.
*
* If configuration succeeds, then call uart_bitbang_enable() on the port.
*
* @param baud_rate: desired baud rate.
* @param parity: 0: no parity, 1: odd parity, 2: even parity.
*
* @returns EC_SUCCESS on success, otherwise an error.
*/
int uart_bitbang_config(int baud_rate, int parity);
/**
* Enable bit banging mode for a UART.
*
* The UART must have been configured first.
*/
int uart_bitbang_enable(void);
/**
* Disable bit banging mode for a UART.
*/
int uart_bitbang_disable(void);
/**
* Returns 1 if bit banging mode is enabled for the UART.
*/
int uart_bitbang_is_enabled(void);
/**
* Returns 1 if bit banging mode is wanted for the UART.
*/
int uart_bitbang_is_wanted(void);
/**
* TX a character on a UART configured for bit banging mode.
*
* @param c: Character to send out.
*/
void uart_bitbang_write_char(char c);
/**
* Sample the RX line on a UART configured for bit banging mode.
*
* This is called when a falling edge is seen on the RX line and will attempt to
* receive a character. Incoming data with framing errors or parity errors will
* be discarded.
*
* @returns EC_SUCCESS if a character was successfully received, EC_ERROR_CRC if
* there was a framing or parity issue.
*/
int uart_bitbang_receive_char(void);
/**
* Returns 1 if there are characters available for consumption, otherwise 0.
*/
int uart_bitbang_is_char_available(void);
/**
* Retrieve a character from the bit bang RX buffer.
*/
int uart_bitbang_read_char(void);
#endif /* __CROS_EC_CHIP_G_UART_BITBANG_H */
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