diff options
Diffstat (limited to 'drivers/serial/serial_lpuart.c')
| -rw-r--r-- | drivers/serial/serial_lpuart.c | 132 | 
1 files changed, 132 insertions, 0 deletions
| diff --git a/drivers/serial/serial_lpuart.c b/drivers/serial/serial_lpuart.c new file mode 100644 index 000000000..51d56662c --- /dev/null +++ b/drivers/serial/serial_lpuart.c @@ -0,0 +1,132 @@ +/* + * Copyright 2013 Freescale Semiconductor, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA + * + */ + +#include <common.h> +#include <watchdog.h> +#include <asm/io.h> +#include <serial.h> +#include <linux/compiler.h> +#include <asm/arch/imx-regs.h> +#include <asm/arch/clock.h> + +#define US1_TDRE        (1 << 7) +#define US1_RDRF        (1 << 5) +#define UC2_TE          (1 << 3) +#define UC2_RE          (1 << 2) + +DECLARE_GLOBAL_DATA_PTR; + +struct lpuart_fsl *base = (struct lpuart_fsl *)LPUART_BASE; + +static void lpuart_serial_setbrg(void) +{ +	u32 clk = mxc_get_clock(MXC_UART_CLK); +	u16 sbr; + +	if (!gd->baudrate) +		gd->baudrate = CONFIG_BAUDRATE; + +	sbr = (u16)(clk / (16 * gd->baudrate)); +	/* place adjustment later - n/32 BRFA */ + +	__raw_writeb(sbr >> 8, &base->ubdh); +	__raw_writeb(sbr & 0xff, &base->ubdl); +} + +static int lpuart_serial_getc(void) +{ +	u8 status; + +	while (!(__raw_readb(&base->us1) & US1_RDRF)) +		WATCHDOG_RESET(); + +	status = __raw_readb(&base->us1); +	status |= US1_RDRF; +	__raw_writeb(status, &base->us1); + +	return __raw_readb(&base->ud); +} + +static void lpuart_serial_putc(const char c) +{ +	if (c == '\n') +		serial_putc('\r'); + +	while (!(__raw_readb(&base->us1) & US1_TDRE)) +		WATCHDOG_RESET(); + +	__raw_writeb(c, &base->ud); +} + +/* + * Test whether a character is in the RX buffer + */ +static int lpuart_serial_tstc(void) +{ +	if (__raw_readb(&base->urcfifo) == 0) +		return 0; + +	return 1; +} + +/* + * Initialise the serial port with the given baudrate. The settings + * are always 8 data bits, no parity, 1 stop bit, no start bits. + */ +static int lpuart_serial_init(void) +{ +	u8 ctrl; + +	ctrl = __raw_readb(&base->uc2); +	ctrl &= ~UC2_RE; +	ctrl &= ~UC2_TE; +	__raw_writeb(ctrl, &base->uc2); + +	__raw_writeb(0, &base->umodem); +	__raw_writeb(0, &base->uc1); + +	/* provide data bits, parity, stop bit, etc */ + +	serial_setbrg(); + +	__raw_writeb(UC2_RE | UC2_TE, &base->uc2); + +	return 0; +} + +static struct serial_device lpuart_serial_drv = { +	.name = "lpuart_serial", +	.start = lpuart_serial_init, +	.stop = NULL, +	.setbrg = lpuart_serial_setbrg, +	.putc = lpuart_serial_putc, +	.puts = default_serial_puts, +	.getc = lpuart_serial_getc, +	.tstc = lpuart_serial_tstc, +}; + +void lpuart_serial_initialize(void) +{ +	serial_register(&lpuart_serial_drv); +} + +__weak struct serial_device *default_serial_console(void) +{ +	return &lpuart_serial_drv; +} |