summaryrefslogtreecommitdiff
path: root/drivers/tty/serial/mrst_max3110.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/tty/serial/mrst_max3110.c')
-rw-r--r--drivers/tty/serial/mrst_max3110.c919
1 files changed, 919 insertions, 0 deletions
diff --git a/drivers/tty/serial/mrst_max3110.c b/drivers/tty/serial/mrst_max3110.c
new file mode 100644
index 000000000000..b62857bf2fdb
--- /dev/null
+++ b/drivers/tty/serial/mrst_max3110.c
@@ -0,0 +1,919 @@
+/*
+ * mrst_max3110.c - spi uart protocol driver for Maxim 3110
+ *
+ * Copyright (c) 2008-2010, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/*
+ * Note:
+ * 1. From Max3110 spec, the Rx FIFO has 8 words, while the Tx FIFO only has
+ * 1 word. If SPI master controller doesn't support sclk frequency change,
+ * then the char need be sent out one by one with some delay
+ *
+ * 2. Currently only RX availabe interrrupt is used, no need for waiting TXE
+ * interrupt for a low speed UART device
+ */
+
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/irq.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial_core.h>
+#include <linux/serial_reg.h>
+
+#include <linux/kthread.h>
+#include <linux/spi/spi.h>
+
+#include "mrst_max3110.h"
+
+#define PR_FMT "mrst_max3110: "
+
+#define UART_TX_NEEDED 1
+#define CON_TX_NEEDED 2
+#define BIT_IRQ_PENDING 3
+
+struct uart_max3110 {
+ struct uart_port port;
+ struct spi_device *spi;
+ char name[24];
+
+ wait_queue_head_t wq;
+ struct task_struct *main_thread;
+ struct task_struct *read_thread;
+ struct mutex thread_mutex;;
+
+ u32 baud;
+ u16 cur_conf;
+ u8 clock;
+ u8 parity, word_7bits;
+ u16 irq;
+
+ unsigned long uart_flags;
+
+ /* console related */
+ struct circ_buf con_xmit;
+};
+
+/* global data structure, may need be removed */
+static struct uart_max3110 *pmax;
+
+static void receive_chars(struct uart_max3110 *max,
+ unsigned char *str, int len);
+static int max3110_read_multi(struct uart_max3110 *max, u8 *buf);
+static void max3110_con_receive(struct uart_max3110 *max);
+
+static int max3110_write_then_read(struct uart_max3110 *max,
+ const void *txbuf, void *rxbuf, unsigned len, int always_fast)
+{
+ struct spi_device *spi = max->spi;
+ struct spi_message message;
+ struct spi_transfer x;
+ int ret;
+
+ spi_message_init(&message);
+ memset(&x, 0, sizeof x);
+ x.len = len;
+ x.tx_buf = txbuf;
+ x.rx_buf = rxbuf;
+ spi_message_add_tail(&x, &message);
+
+ if (always_fast)
+ x.speed_hz = spi->max_speed_hz;
+ else if (max->baud)
+ x.speed_hz = max->baud;
+
+ /* Do the i/o */
+ ret = spi_sync(spi, &message);
+ return ret;
+}
+
+/* Write a 16b word to the device */
+static int max3110_out(struct uart_max3110 *max, const u16 out)
+{
+ void *buf;
+ u16 *obuf, *ibuf;
+ u8 ch;
+ int ret;
+
+ buf = kzalloc(8, GFP_KERNEL | GFP_DMA);
+ if (!buf)
+ return -ENOMEM;
+
+ obuf = buf;
+ ibuf = buf + 4;
+ *obuf = out;
+ ret = max3110_write_then_read(max, obuf, ibuf, 2, 1);
+ if (ret) {
+ pr_warning(PR_FMT "%s(): get err msg %d when sending 0x%x\n",
+ __func__, ret, out);
+ goto exit;
+ }
+
+ /* If some valid data is read back */
+ if (*ibuf & MAX3110_READ_DATA_AVAILABLE) {
+ ch = *ibuf & 0xff;
+ receive_chars(max, &ch, 1);
+ }
+
+exit:
+ kfree(buf);
+ return ret;
+}
+
+/*
+ * This is usually used to read data from SPIC RX FIFO, which doesn't
+ * need any delay like flushing character out.
+ *
+ * Return how many valide bytes are read back
+ */
+static int max3110_read_multi(struct uart_max3110 *max, u8 *rxbuf)
+{
+ void *buf;
+ u16 *obuf, *ibuf;
+ u8 *pbuf, valid_str[M3110_RX_FIFO_DEPTH];
+ int i, j, blen;
+
+ blen = M3110_RX_FIFO_DEPTH * sizeof(u16);
+ buf = kzalloc(blen * 2, GFP_KERNEL | GFP_DMA);
+ if (!buf) {
+ pr_warning(PR_FMT "%s(): fail to alloc dma buffer\n", __func__);
+ return 0;
+ }
+
+ /* tx/rx always have the same length */
+ obuf = buf;
+ ibuf = buf + blen;
+
+ if (max3110_write_then_read(max, obuf, ibuf, blen, 1)) {
+ kfree(buf);
+ return 0;
+ }
+
+ /* If caller doesn't provide a buffer, then handle received char */
+ pbuf = rxbuf ? rxbuf : valid_str;
+
+ for (i = 0, j = 0; i < M3110_RX_FIFO_DEPTH; i++) {
+ if (ibuf[i] & MAX3110_READ_DATA_AVAILABLE)
+ pbuf[j++] = ibuf[i] & 0xff;
+ }
+
+ if (j && (pbuf == valid_str))
+ receive_chars(max, valid_str, j);
+
+ kfree(buf);
+ return j;
+}
+
+static void serial_m3110_con_putchar(struct uart_port *port, int ch)
+{
+ struct uart_max3110 *max =
+ container_of(port, struct uart_max3110, port);
+ struct circ_buf *xmit = &max->con_xmit;
+
+ if (uart_circ_chars_free(xmit)) {
+ xmit->buf[xmit->head] = (char)ch;
+ xmit->head = (xmit->head + 1) & (PAGE_SIZE - 1);
+ }
+}
+
+/*
+ * Print a string to the serial port trying not to disturb
+ * any possible real use of the port...
+ *
+ * The console_lock must be held when we get here.
+ */
+static void serial_m3110_con_write(struct console *co,
+ const char *s, unsigned int count)
+{
+ if (!pmax)
+ return;
+
+ uart_console_write(&pmax->port, s, count, serial_m3110_con_putchar);
+
+ if (!test_and_set_bit(CON_TX_NEEDED, &pmax->uart_flags))
+ wake_up_process(pmax->main_thread);
+}
+
+static int __init
+serial_m3110_con_setup(struct console *co, char *options)
+{
+ struct uart_max3110 *max = pmax;
+ int baud = 115200;
+ int bits = 8;
+ int parity = 'n';
+ int flow = 'n';
+
+ pr_info(PR_FMT "setting up console\n");
+
+ if (co->index == -1)
+ co->index = 0;
+
+ if (!max) {
+ pr_err(PR_FMT "pmax is NULL, return");
+ return -ENODEV;
+ }
+
+ if (options)
+ uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+ return uart_set_options(&max->port, co, baud, parity, bits, flow);
+}
+
+static struct tty_driver *serial_m3110_con_device(struct console *co,
+ int *index)
+{
+ struct uart_driver *p = co->data;
+ *index = co->index;
+ return p->tty_driver;
+}
+
+static struct uart_driver serial_m3110_reg;
+static struct console serial_m3110_console = {
+ .name = "ttyS",
+ .write = serial_m3110_con_write,
+ .device = serial_m3110_con_device,
+ .setup = serial_m3110_con_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+ .data = &serial_m3110_reg,
+};
+
+static unsigned int serial_m3110_tx_empty(struct uart_port *port)
+{
+ return 1;
+}
+
+static void serial_m3110_stop_tx(struct uart_port *port)
+{
+ return;
+}
+
+/* stop_rx will be called in spin_lock env */
+static void serial_m3110_stop_rx(struct uart_port *port)
+{
+ return;
+}
+
+#define WORDS_PER_XFER 128
+static void send_circ_buf(struct uart_max3110 *max,
+ struct circ_buf *xmit)
+{
+ void *buf;
+ u16 *obuf, *ibuf;
+ u8 valid_str[WORDS_PER_XFER];
+ int i, j, len, blen, dma_size, left, ret = 0;
+
+
+ dma_size = WORDS_PER_XFER * sizeof(u16) * 2;
+ buf = kzalloc(dma_size, GFP_KERNEL | GFP_DMA);
+ if (!buf)
+ return;
+ obuf = buf;
+ ibuf = buf + dma_size/2;
+
+ while (!uart_circ_empty(xmit)) {
+ left = uart_circ_chars_pending(xmit);
+ while (left) {
+ len = min(left, WORDS_PER_XFER);
+ blen = len * sizeof(u16);
+ memset(ibuf, 0, blen);
+
+ for (i = 0; i < len; i++) {
+ obuf[i] = (u8)xmit->buf[xmit->tail] | WD_TAG;
+ xmit->tail = (xmit->tail + 1) &
+ (UART_XMIT_SIZE - 1);
+ }
+
+ /* Fail to send msg to console is not very critical */
+ ret = max3110_write_then_read(max, obuf, ibuf, blen, 0);
+ if (ret)
+ pr_warning(PR_FMT "%s(): get err msg %d\n",
+ __func__, ret);
+
+ for (i = 0, j = 0; i < len; i++) {
+ if (ibuf[i] & MAX3110_READ_DATA_AVAILABLE)
+ valid_str[j++] = ibuf[i] & 0xff;
+ }
+
+ if (j)
+ receive_chars(max, valid_str, j);
+
+ max->port.icount.tx += len;
+ left -= len;
+ }
+ }
+
+ kfree(buf);
+}
+
+static void transmit_char(struct uart_max3110 *max)
+{
+ struct uart_port *port = &max->port;
+ struct circ_buf *xmit = &port->state->xmit;
+
+ if (uart_circ_empty(xmit) || uart_tx_stopped(port))
+ return;
+
+ send_circ_buf(max, xmit);
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(port);
+
+ if (uart_circ_empty(xmit))
+ serial_m3110_stop_tx(port);
+}
+
+/*
+ * This will be called by uart_write() and tty_write, can't
+ * go to sleep
+ */
+static void serial_m3110_start_tx(struct uart_port *port)
+{
+ struct uart_max3110 *max =
+ container_of(port, struct uart_max3110, port);
+
+ if (!test_and_set_bit(UART_TX_NEEDED, &max->uart_flags))
+ wake_up_process(max->main_thread);
+}
+
+static void receive_chars(struct uart_max3110 *max, unsigned char *str, int len)
+{
+ struct uart_port *port = &max->port;
+ struct tty_struct *tty;
+ int usable;
+
+ /* If uart is not opened, just return */
+ if (!port->state)
+ return;
+
+ tty = port->state->port.tty;
+ if (!tty)
+ return;
+
+ while (len) {
+ usable = tty_buffer_request_room(tty, len);
+ if (usable) {
+ tty_insert_flip_string(tty, str, usable);
+ str += usable;
+ port->icount.rx += usable;
+ }
+ len -= usable;
+ }
+ tty_flip_buffer_push(tty);
+}
+
+/*
+ * This routine will be used in read_thread or RX IRQ handling,
+ * it will first do one round buffer read(8 words), if there is some
+ * valid RX data, will try to read 5 more rounds till all data
+ * is read out.
+ *
+ * Use stack space as data buffer to save some system load, and chose
+ * 504 Btyes as a threadhold to do a bulk push to upper tty layer when
+ * receiving bulk data, a much bigger buffer may cause stack overflow
+ */
+static void max3110_con_receive(struct uart_max3110 *max)
+{
+ int loop = 1, num, total = 0;
+ u8 recv_buf[512], *pbuf;
+
+ pbuf = recv_buf;
+ do {
+ num = max3110_read_multi(max, pbuf);
+
+ if (num) {
+ loop = 5;
+ pbuf += num;
+ total += num;
+
+ if (total >= 504) {
+ receive_chars(max, recv_buf, total);
+ pbuf = recv_buf;
+ total = 0;
+ }
+ }
+ } while (--loop);
+
+ if (total)
+ receive_chars(max, recv_buf, total);
+}
+
+static int max3110_main_thread(void *_max)
+{
+ struct uart_max3110 *max = _max;
+ wait_queue_head_t *wq = &max->wq;
+ int ret = 0;
+ struct circ_buf *xmit = &max->con_xmit;
+
+ init_waitqueue_head(wq);
+ pr_info(PR_FMT "start main thread\n");
+
+ do {
+ wait_event_interruptible(*wq, max->uart_flags || kthread_should_stop());
+
+ mutex_lock(&max->thread_mutex);
+
+ if (test_and_clear_bit(BIT_IRQ_PENDING, &max->uart_flags))
+ max3110_con_receive(max);
+
+ /* first handle console output */
+ if (test_and_clear_bit(CON_TX_NEEDED, &max->uart_flags))
+ send_circ_buf(max, xmit);
+
+ /* handle uart output */
+ if (test_and_clear_bit(UART_TX_NEEDED, &max->uart_flags))
+ transmit_char(max);
+
+ mutex_unlock(&max->thread_mutex);
+
+ } while (!kthread_should_stop());
+
+ return ret;
+}
+
+static irqreturn_t serial_m3110_irq(int irq, void *dev_id)
+{
+ struct uart_max3110 *max = dev_id;
+
+ /* max3110's irq is a falling edge, not level triggered,
+ * so no need to disable the irq */
+ if (!test_and_set_bit(BIT_IRQ_PENDING, &max->uart_flags))
+ wake_up_process(max->main_thread);
+
+ return IRQ_HANDLED;
+}
+
+/* if don't use RX IRQ, then need a thread to polling read */
+static int max3110_read_thread(void *_max)
+{
+ struct uart_max3110 *max = _max;
+
+ pr_info(PR_FMT "start read thread\n");
+ do {
+ /*
+ * If can't acquire the mutex, it means the main thread
+ * is running which will also perform the rx job
+ */
+ if (mutex_trylock(&max->thread_mutex)) {
+ max3110_con_receive(max);
+ mutex_unlock(&max->thread_mutex);
+ }
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout(HZ / 20);
+ } while (!kthread_should_stop());
+
+ return 0;
+}
+
+static int serial_m3110_startup(struct uart_port *port)
+{
+ struct uart_max3110 *max =
+ container_of(port, struct uart_max3110, port);
+ u16 config = 0;
+ int ret = 0;
+
+ if (port->line != 0) {
+ pr_err(PR_FMT "uart port startup failed\n");
+ return -1;
+ }
+
+ /* Disable all IRQ and config it to 115200, 8n1 */
+ config = WC_TAG | WC_FIFO_ENABLE
+ | WC_1_STOPBITS
+ | WC_8BIT_WORD
+ | WC_BAUD_DR2;
+
+ /* as we use thread to handle tx/rx, need set low latency */
+ port->state->port.tty->low_latency = 1;
+
+ if (max->irq) {
+ max->read_thread = NULL;
+ ret = request_irq(max->irq, serial_m3110_irq,
+ IRQ_TYPE_EDGE_FALLING, "max3110", max);
+ if (ret) {
+ max->irq = 0;
+ pr_err(PR_FMT "unable to allocate IRQ, polling\n");
+ } else {
+ /* Enable RX IRQ only */
+ config |= WC_RXA_IRQ_ENABLE;
+ }
+ }
+
+ if (max->irq == 0) {
+ /* If IRQ is disabled, start a read thread for input data */
+ max->read_thread =
+ kthread_run(max3110_read_thread, max, "max3110_read");
+ if (IS_ERR(max->read_thread)) {
+ ret = PTR_ERR(max->read_thread);
+ max->read_thread = NULL;
+ pr_err(PR_FMT "Can't create read thread!\n");
+ return ret;
+ }
+ }
+
+ ret = max3110_out(max, config);
+ if (ret) {
+ if (max->irq)
+ free_irq(max->irq, max);
+ if (max->read_thread)
+ kthread_stop(max->read_thread);
+ max->read_thread = NULL;
+ return ret;
+ }
+
+ max->cur_conf = config;
+ return 0;
+}
+
+static void serial_m3110_shutdown(struct uart_port *port)
+{
+ struct uart_max3110 *max =
+ container_of(port, struct uart_max3110, port);
+ u16 config;
+
+ if (max->read_thread) {
+ kthread_stop(max->read_thread);
+ max->read_thread = NULL;
+ }
+
+ if (max->irq)
+ free_irq(max->irq, max);
+
+ /* Disable interrupts from this port */
+ config = WC_TAG | WC_SW_SHDI;
+ max3110_out(max, config);
+}
+
+static void serial_m3110_release_port(struct uart_port *port)
+{
+}
+
+static int serial_m3110_request_port(struct uart_port *port)
+{
+ return 0;
+}
+
+static void serial_m3110_config_port(struct uart_port *port, int flags)
+{
+ port->type = PORT_MAX3100;
+}
+
+static int
+serial_m3110_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+ /* we don't want the core code to modify any port params */
+ return -EINVAL;
+}
+
+
+static const char *serial_m3110_type(struct uart_port *port)
+{
+ struct uart_max3110 *max =
+ container_of(port, struct uart_max3110, port);
+ return max->name;
+}
+
+static void
+serial_m3110_set_termios(struct uart_port *port, struct ktermios *termios,
+ struct ktermios *old)
+{
+ struct uart_max3110 *max =
+ container_of(port, struct uart_max3110, port);
+ unsigned char cval;
+ unsigned int baud, parity = 0;
+ int clk_div = -1;
+ u16 new_conf = max->cur_conf;
+
+ switch (termios->c_cflag & CSIZE) {
+ case CS7:
+ cval = UART_LCR_WLEN7;
+ new_conf |= WC_7BIT_WORD;
+ break;
+ default:
+ /* We only support CS7 & CS8 */
+ termios->c_cflag &= ~CSIZE;
+ termios->c_cflag |= CS8;
+ case CS8:
+ cval = UART_LCR_WLEN8;
+ new_conf |= WC_8BIT_WORD;
+ break;
+ }
+
+ baud = uart_get_baud_rate(port, termios, old, 0, 230400);
+
+ /* First calc the div for 1.8MHZ clock case */
+ switch (baud) {
+ case 300:
+ clk_div = WC_BAUD_DR384;
+ break;
+ case 600:
+ clk_div = WC_BAUD_DR192;
+ break;
+ case 1200:
+ clk_div = WC_BAUD_DR96;
+ break;
+ case 2400:
+ clk_div = WC_BAUD_DR48;
+ break;
+ case 4800:
+ clk_div = WC_BAUD_DR24;
+ break;
+ case 9600:
+ clk_div = WC_BAUD_DR12;
+ break;
+ case 19200:
+ clk_div = WC_BAUD_DR6;
+ break;
+ case 38400:
+ clk_div = WC_BAUD_DR3;
+ break;
+ case 57600:
+ clk_div = WC_BAUD_DR2;
+ break;
+ case 115200:
+ clk_div = WC_BAUD_DR1;
+ break;
+ case 230400:
+ if (max->clock & MAX3110_HIGH_CLK)
+ break;
+ default:
+ /* Pick the previous baud rate */
+ baud = max->baud;
+ clk_div = max->cur_conf & WC_BAUD_DIV_MASK;
+ tty_termios_encode_baud_rate(termios, baud, baud);
+ }
+
+ if (max->clock & MAX3110_HIGH_CLK) {
+ clk_div += 1;
+ /* High clk version max3110 doesn't support B300 */
+ if (baud == 300) {
+ baud = 600;
+ clk_div = WC_BAUD_DR384;
+ }
+ if (baud == 230400)
+ clk_div = WC_BAUD_DR1;
+ tty_termios_encode_baud_rate(termios, baud, baud);
+ }
+
+ new_conf = (new_conf & ~WC_BAUD_DIV_MASK) | clk_div;
+
+ if (unlikely(termios->c_cflag & CMSPAR))
+ termios->c_cflag &= ~CMSPAR;
+
+ if (termios->c_cflag & CSTOPB)
+ new_conf |= WC_2_STOPBITS;
+ else
+ new_conf &= ~WC_2_STOPBITS;
+
+ if (termios->c_cflag & PARENB) {
+ new_conf |= WC_PARITY_ENABLE;
+ parity |= UART_LCR_PARITY;
+ } else
+ new_conf &= ~WC_PARITY_ENABLE;
+
+ if (!(termios->c_cflag & PARODD))
+ parity |= UART_LCR_EPAR;
+ max->parity = parity;
+
+ uart_update_timeout(port, termios->c_cflag, baud);
+
+ new_conf |= WC_TAG;
+ if (new_conf != max->cur_conf) {
+ if (!max3110_out(max, new_conf)) {
+ max->cur_conf = new_conf;
+ max->baud = baud;
+ }
+ }
+}
+
+/* Don't handle hw handshaking */
+static unsigned int serial_m3110_get_mctrl(struct uart_port *port)
+{
+ return TIOCM_DSR | TIOCM_CAR | TIOCM_DSR;
+}
+
+static void serial_m3110_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+}
+
+static void serial_m3110_break_ctl(struct uart_port *port, int break_state)
+{
+}
+
+static void serial_m3110_pm(struct uart_port *port, unsigned int state,
+ unsigned int oldstate)
+{
+}
+
+static void serial_m3110_enable_ms(struct uart_port *port)
+{
+}
+
+struct uart_ops serial_m3110_ops = {
+ .tx_empty = serial_m3110_tx_empty,
+ .set_mctrl = serial_m3110_set_mctrl,
+ .get_mctrl = serial_m3110_get_mctrl,
+ .stop_tx = serial_m3110_stop_tx,
+ .start_tx = serial_m3110_start_tx,
+ .stop_rx = serial_m3110_stop_rx,
+ .enable_ms = serial_m3110_enable_ms,
+ .break_ctl = serial_m3110_break_ctl,
+ .startup = serial_m3110_startup,
+ .shutdown = serial_m3110_shutdown,
+ .set_termios = serial_m3110_set_termios,
+ .pm = serial_m3110_pm,
+ .type = serial_m3110_type,
+ .release_port = serial_m3110_release_port,
+ .request_port = serial_m3110_request_port,
+ .config_port = serial_m3110_config_port,
+ .verify_port = serial_m3110_verify_port,
+};
+
+static struct uart_driver serial_m3110_reg = {
+ .owner = THIS_MODULE,
+ .driver_name = "MRST serial",
+ .dev_name = "ttyS",
+ .major = TTY_MAJOR,
+ .minor = 64,
+ .nr = 1,
+ .cons = &serial_m3110_console,
+};
+
+#ifdef CONFIG_PM
+static int serial_m3110_suspend(struct spi_device *spi, pm_message_t state)
+{
+ struct uart_max3110 *max = spi_get_drvdata(spi);
+
+ disable_irq(max->irq);
+ uart_suspend_port(&serial_m3110_reg, &max->port);
+ max3110_out(max, max->cur_conf | WC_SW_SHDI);
+ return 0;
+}
+
+static int serial_m3110_resume(struct spi_device *spi)
+{
+ struct uart_max3110 *max = spi_get_drvdata(spi);
+
+ max3110_out(max, max->cur_conf);
+ uart_resume_port(&serial_m3110_reg, &max->port);
+ enable_irq(max->irq);
+ return 0;
+}
+#else
+#define serial_m3110_suspend NULL
+#define serial_m3110_resume NULL
+#endif
+
+static int __devinit serial_m3110_probe(struct spi_device *spi)
+{
+ struct uart_max3110 *max;
+ void *buffer;
+ u16 res;
+ int ret = 0;
+
+ max = kzalloc(sizeof(*max), GFP_KERNEL);
+ if (!max)
+ return -ENOMEM;
+
+ /* Set spi info */
+ spi->bits_per_word = 16;
+ max->clock = MAX3110_HIGH_CLK;
+
+ spi_setup(spi);
+
+ max->port.type = PORT_MAX3100;
+ max->port.fifosize = 2; /* Only have 16b buffer */
+ max->port.ops = &serial_m3110_ops;
+ max->port.line = 0;
+ max->port.dev = &spi->dev;
+ max->port.uartclk = 115200;
+
+ max->spi = spi;
+ strcpy(max->name, spi->modalias);
+ max->irq = (u16)spi->irq;
+
+ mutex_init(&max->thread_mutex);
+
+ max->word_7bits = 0;
+ max->parity = 0;
+ max->baud = 0;
+
+ max->cur_conf = 0;
+ max->uart_flags = 0;
+
+ /* Check if reading configuration register returns something sane */
+
+ res = RC_TAG;
+ ret = max3110_write_then_read(max, (u8 *)&res, (u8 *)&res, 2, 0);
+ if (ret < 0 || res == 0 || res == 0xffff) {
+ printk(KERN_ERR "MAX3111 deemed not present (conf reg %04x)",
+ res);
+ ret = -ENODEV;
+ goto err_get_page;
+ }
+
+ buffer = (void *)__get_free_page(GFP_KERNEL);
+ if (!buffer) {
+ ret = -ENOMEM;
+ goto err_get_page;
+ }
+ max->con_xmit.buf = buffer;
+ max->con_xmit.head = 0;
+ max->con_xmit.tail = 0;
+
+ max->main_thread = kthread_run(max3110_main_thread,
+ max, "max3110_main");
+ if (IS_ERR(max->main_thread)) {
+ ret = PTR_ERR(max->main_thread);
+ goto err_kthread;
+ }
+
+ spi_set_drvdata(spi, max);
+ pmax = max;
+
+ /* Give membase a psudo value to pass serial_core's check */
+ max->port.membase = (void *)0xff110000;
+ uart_add_one_port(&serial_m3110_reg, &max->port);
+
+ return 0;
+
+err_kthread:
+ free_page((unsigned long)buffer);
+err_get_page:
+ kfree(max);
+ return ret;
+}
+
+static int __devexit serial_m3110_remove(struct spi_device *dev)
+{
+ struct uart_max3110 *max = spi_get_drvdata(dev);
+
+ if (!max)
+ return 0;
+
+ uart_remove_one_port(&serial_m3110_reg, &max->port);
+
+ free_page((unsigned long)max->con_xmit.buf);
+
+ if (max->main_thread)
+ kthread_stop(max->main_thread);
+
+ kfree(max);
+ return 0;
+}
+
+static struct spi_driver uart_max3110_driver = {
+ .driver = {
+ .name = "spi_max3111",
+ .bus = &spi_bus_type,
+ .owner = THIS_MODULE,
+ },
+ .probe = serial_m3110_probe,
+ .remove = __devexit_p(serial_m3110_remove),
+ .suspend = serial_m3110_suspend,
+ .resume = serial_m3110_resume,
+};
+
+static int __init serial_m3110_init(void)
+{
+ int ret = 0;
+
+ ret = uart_register_driver(&serial_m3110_reg);
+ if (ret)
+ return ret;
+
+ ret = spi_register_driver(&uart_max3110_driver);
+ if (ret)
+ uart_unregister_driver(&serial_m3110_reg);
+
+ return ret;
+}
+
+static void __exit serial_m3110_exit(void)
+{
+ spi_unregister_driver(&uart_max3110_driver);
+ uart_unregister_driver(&serial_m3110_reg);
+}
+
+module_init(serial_m3110_init);
+module_exit(serial_m3110_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("max3110-uart");