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Diffstat (limited to 'chip/g/uart_bitbang.h')
| -rw-r--r-- | chip/g/uart_bitbang.h | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/chip/g/uart_bitbang.h b/chip/g/uart_bitbang.h new file mode 100644 index 0000000000..7a8a33e923 --- /dev/null +++ b/chip/g/uart_bitbang.h @@ -0,0 +1,130 @@ +/* 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 uart: Index of UART to enable bit banging mode. + * @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 uart, int baud_rate, int parity); + +/** + * Enable bit banging mode for a UART. + * + * The UART must have been configured first. + * + * @param uart: Index of UART to disable bit banging mode. + */ +int uart_bitbang_enable(int uart); + +/** + * Disable bit banging mode for a UART. + * + * @param uart: Index of UART to disable bit banging mode. + */ +int uart_bitbang_disable(int uart); + +/** + * Returns 1 if bit banging mode is enabled for the UART. + * + * @param uart: Index of UART to query. + */ +int uart_bitbang_is_enabled(int uart); + +/** + * Returns 1 if bit banging mode is wanted for the UART. + * + * @param uart: Index of UART to query. + */ +int uart_bitbang_is_wanted(int uart); + +/** + * TX a character on a UART configured for bit banging mode. + * + * @param uart: Index of UART to use. + * @param c: Character to send out. + */ +void uart_bitbang_write_char(int uart, 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. + * + * @param uart: Index of UART to use. + * @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(int uart); + +/** + * Returns 1 if there are characters available for consumption, otherwise 0. + * + * @param uart: Index of UART to check. + */ +int uart_bitbang_is_char_available(int uart); + +/** + * Retrieve a character from the bit bang RX buffer. + * + * @param uart: Index of UART to use. + */ +int uart_bitbang_read_char(int uart); + +#endif /* __CROS_EC_CHIP_G_UART_BITBANG_H */ |