diff options
Diffstat (limited to 'drivers/serial/mxs_auart.c')
| -rw-r--r-- | drivers/serial/mxs_auart.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/drivers/serial/mxs_auart.c b/drivers/serial/mxs_auart.c new file mode 100644 index 0000000..7cfe5bc --- /dev/null +++ b/drivers/serial/mxs_auart.c @@ -0,0 +1,151 @@ +/* + * Freescale i.MX23/i.MX28 AUART driver + * + * Copyright (C) 2013 Andreas Wass <andreas.wass@dalelven.com> + * + * Based on the MXC serial driver: + * + * (c) 2007 Sascha Hauer <s.hauer@pengutronix.de> + * + * Further based on the Linux mxs-auart.c driver: + * + * Freescale STMP37XX/STMP38X Application UART drkiver + * Copyright 2008-2010 Freescale Semiconductor, Inc. + * + * SPDX-License-Identifier: GPL-2.0+ + */ +#include <common.h> +#include <asm/io.h> +#include <serial.h> +#include <linux/compiler.h> +#include <asm/arch/regs-base.h> +#include <asm/arch/regs-uartapp.h> +#include <asm/arch/sys_proto.h> + +DECLARE_GLOBAL_DATA_PTR; + +#ifndef CONFIG_MXS_AUART_BASE +#error "CONFIG_MXS_AUART_BASE must be set to the base UART to use" +#endif + +/* AUART clock always supplied by XTAL and always 24MHz */ +#define MXS_AUART_CLK 24000000 + +static struct mxs_uartapp_regs *get_uartapp_registers(void) +{ + return (struct mxs_uartapp_regs *)CONFIG_MXS_AUART_BASE; +} + +/** + * Sets the baud rate and settings. + * The settings are: 8 data bits, no parit and 1 stop bit. + */ +void mxs_auart_setbrg(void) +{ + u32 div; + u32 linectrl = 0; + struct mxs_uartapp_regs *regs = get_uartapp_registers(); + + if (!gd->baudrate) + gd->baudrate = CONFIG_BAUDRATE; + + /* + * From i.MX28 datasheet: + * div is calculated by calculating UARTCLK*32/baudrate, rounded to int + * div must be between 0xEC and 0x003FFFC0 inclusive + * Lowest 6 bits of div goes in BAUD_DIVFRAC part of LINECTRL register + * Next 16 bits goes in BAUD_DIVINT part of LINECTRL register + */ + div = (MXS_AUART_CLK * 32) / gd->baudrate; + if (div < 0xEC || div > 0x003FFFC0) + return; + + linectrl |= ((div & UARTAPP_LINECTRL_EXTRACT_BAUD_DIVFRAC_MASK) << + UARTAPP_LINECTRL_BAUD_DIVFRAC_OFFSET) & + UARTAPP_LINECTRL_BAUD_DIVFRAC_MASK; + linectrl |= ((div >> UARTAPP_LINECTRL_EXTRACT_BAUD_DIVINT_OFFSET) << + UARTAPP_LINECTRL_BAUD_DIVINT_OFFSET) & + UARTAPP_LINECTRL_BAUD_DIVINT_MASK; + + /* Word length: 8 bits */ + linectrl |= UARTAPP_LINECTRL_WLEN_8BITS; + + /* Enable FIFOs. */ + linectrl |= UARTAPP_LINECTRL_FEN_MASK; + + /* Write above settings, no parity, 1 stop bit */ + writel(linectrl, ®s->hw_uartapp_linectrl); +} + +int mxs_auart_init(void) +{ + struct mxs_uartapp_regs *regs = get_uartapp_registers(); + /* Reset everything */ + mxs_reset_block(®s->hw_uartapp_ctrl0_reg); + /* Disable interrupts */ + writel(0, ®s->hw_uartapp_intr); + /* Set baud rate and settings */ + serial_setbrg(); + /* Disable RTS and CTS, ignore LINECTRL2 register */ + writel(UARTAPP_CTRL2_RTSEN_MASK | + UARTAPP_CTRL2_CTSEN_MASK | + UARTAPP_CTRL2_USE_LCR2_MASK, + ®s->hw_uartapp_ctrl2_clr); + /* Enable receiver, transmitter and UART */ + writel(UARTAPP_CTRL2_RXE_MASK | + UARTAPP_CTRL2_TXE_MASK | + UARTAPP_CTRL2_UARTEN_MASK, + ®s->hw_uartapp_ctrl2_set); + return 0; +} + +void mxs_auart_putc(const char c) +{ + struct mxs_uartapp_regs *regs = get_uartapp_registers(); + /* Wait in loop while the transmit FIFO is full */ + while (readl(®s->hw_uartapp_stat) & UARTAPP_STAT_TXFF_MASK) + ; + + writel(c, ®s->hw_uartapp_data); + + if (c == '\n') + mxs_auart_putc('\r'); +} + +int mxs_auart_tstc(void) +{ + struct mxs_uartapp_regs *regs = get_uartapp_registers(); + /* Checks if receive FIFO is empty */ + return !(readl(®s->hw_uartapp_stat) & UARTAPP_STAT_RXFE_MASK); +} + +int mxs_auart_getc(void) +{ + struct mxs_uartapp_regs *regs = get_uartapp_registers(); + /* Wait until a character is available to read */ + while (!mxs_auart_tstc()) + ; + /* Read the character from the data register */ + return readl(®s->hw_uartapp_data) & 0xFF; +} + +static struct serial_device mxs_auart_drv = { + .name = "mxs_auart_serial", + .start = mxs_auart_init, + .stop = NULL, + .setbrg = mxs_auart_setbrg, + .putc = mxs_auart_putc, + .puts = default_serial_puts, + .getc = mxs_auart_getc, + .tstc = mxs_auart_tstc, +}; + +void mxs_auart_initialize(void) +{ + serial_register(&mxs_auart_drv); +} + +__weak struct serial_device *default_serial_console(void) +{ + return &mxs_auart_drv; +} |