path: root/drivers/tty/serial/max3107.c

/*
 *  max3107.c - spi uart protocol driver for Maxim 3107
 *  Based on max3100.c
 *	by Christian Pellegrin <chripell@evolware.org>
 *  and	max3110.c
 *	by Feng Tang <feng.tang@intel.com>
 *
 *  Copyright (C) Aavamobile 2009
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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 <linux/delay.h>
#include <linux/device.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <linux/freezer.h>
#include <linux/module.h>
#include "max3107.h"

static const struct baud_table brg26_ext[] = {
	{ 300,    MAX3107_BRG26_B300 },
	{ 600,    MAX3107_BRG26_B600 },
	{ 1200,   MAX3107_BRG26_B1200 },
	{ 2400,   MAX3107_BRG26_B2400 },
	{ 4800,   MAX3107_BRG26_B4800 },
	{ 9600,   MAX3107_BRG26_B9600 },
	{ 19200,  MAX3107_BRG26_B19200 },
	{ 57600,  MAX3107_BRG26_B57600 },
	{ 115200, MAX3107_BRG26_B115200 },
	{ 230400, MAX3107_BRG26_B230400 },
	{ 460800, MAX3107_BRG26_B460800 },
	{ 921600, MAX3107_BRG26_B921600 },
	{ 0, 0 }
};

static const struct baud_table brg13_int[] = {
	{ 300,    MAX3107_BRG13_IB300 },
	{ 600,    MAX3107_BRG13_IB600 },
	{ 1200,   MAX3107_BRG13_IB1200 },
	{ 2400,   MAX3107_BRG13_IB2400 },
	{ 4800,   MAX3107_BRG13_IB4800 },
	{ 9600,   MAX3107_BRG13_IB9600 },
	{ 19200,  MAX3107_BRG13_IB19200 },
	{ 57600,  MAX3107_BRG13_IB57600 },
	{ 115200, MAX3107_BRG13_IB115200 },
	{ 230400, MAX3107_BRG13_IB230400 },
	{ 460800, MAX3107_BRG13_IB460800 },
	{ 921600, MAX3107_BRG13_IB921600 },
	{ 0, 0 }
};

static u32 get_new_brg(int baud, struct max3107_port *s)
{
	int i;
	const struct baud_table *baud_tbl = s->baud_tbl;

	for (i = 0; i < 13; i++) {
		if (baud == baud_tbl[i].baud)
			return baud_tbl[i].new_brg;
	}

	return 0;
}

/* Perform SPI transfer for write/read of device register(s) */
int max3107_rw(struct max3107_port *s, u8 *tx, u8 *rx, int len)
{
	struct spi_message spi_msg;
	struct spi_transfer spi_xfer;

	/* Initialize SPI ,message */
	spi_message_init(&spi_msg);

	/* Initialize SPI transfer */
	memset(&spi_xfer, 0, sizeof spi_xfer);
	spi_xfer.len = len;
	spi_xfer.tx_buf = tx;
	spi_xfer.rx_buf = rx;
	spi_xfer.speed_hz = MAX3107_SPI_SPEED;

	/* Add SPI transfer to SPI message */
	spi_message_add_tail(&spi_xfer, &spi_msg);

#ifdef DBG_TRACE_SPI_DATA
	{
		int i;
		pr_info("tx len %d:\n", spi_xfer.len);
		for (i = 0 ; i < spi_xfer.len && i < 32 ; i++)
			pr_info(" %x", ((u8 *)spi_xfer.tx_buf)[i]);
		pr_info("\n");
	}
#endif

	/* Perform synchronous SPI transfer */
	if (spi_sync(s->spi, &spi_msg)) {
		dev_err(&s->spi->dev, "spi_sync failure\n");
		return -EIO;
	}

#ifdef DBG_TRACE_SPI_DATA
	if (spi_xfer.rx_buf) {
		int i;
		pr_info("rx len %d:\n", spi_xfer.len);
		for (i = 0 ; i < spi_xfer.len && i < 32 ; i++)
			pr_info(" %x", ((u8 *)spi_xfer.rx_buf)[i]);
		pr_info("\n");
	}
#endif
	return 0;
}
EXPORT_SYMBOL_GPL(max3107_rw);

/* Puts received data to circular buffer */
static void put_data_to_circ_buf(struct max3107_port *s, unsigned char *data,
					int len)
{
	struct uart_port *port = &s->port;
	struct tty_struct *tty;

	if (!port->state)
		return;

	tty = port->state->port.tty;
	if (!tty)
		return;

	/* Insert received data */
	tty_insert_flip_string(tty, data, len);
	/* Update RX counter */
	port->icount.rx += len;
}

/* Handle data receiving */
static void max3107_handlerx(struct max3107_port *s, u16 rxlvl)
{
	int i;
	int j;
	int len;				/* SPI transfer buffer length */
	u16 *buf;
	u8 *valid_str;

	if (!s->rx_enabled)
		/* RX is disabled */
		return;

	if (rxlvl == 0) {
		/* RX fifo is empty */
		return;
	} else if (rxlvl >= MAX3107_RX_FIFO_SIZE) {
		dev_warn(&s->spi->dev, "Possible RX FIFO overrun %d\n", rxlvl);
		/* Ensure sanity of RX level */
		rxlvl = MAX3107_RX_FIFO_SIZE;
	}
	if ((s->rxbuf == 0) || (s->rxstr == 0)) {
		dev_warn(&s->spi->dev, "Rx buffer/str isn't ready\n");
		return;
	}
	buf = s->rxbuf;
	valid_str = s->rxstr;
	while (rxlvl) {
		pr_debug("rxlvl %d\n", rxlvl);