Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / tty / serial / max3100.c
diff --git a/kernel/drivers/tty/serial/max3100.c b/kernel/drivers/tty/serial/max3100.c
new file mode 100644 (file)
index 0000000..0773772
--- /dev/null
@@ -0,0 +1,919 @@
+/*
+ *
+ *  Copyright (C) 2008 Christian Pellegrin <chripell@evolware.org>
+ *
+ * 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.
+ *
+ *
+ * Notes: the MAX3100 doesn't provide an interrupt on CTS so we have
+ * to use polling for flow control. TX empty IRQ is unusable, since
+ * writing conf clears FIFO buffer and we cannot have this interrupt
+ * always asking us for attention.
+ *
+ * Example platform data:
+
+ static struct plat_max3100 max3100_plat_data = {
+ .loopback = 0,
+ .crystal = 0,
+ .poll_time = 100,
+ };
+
+ static struct spi_board_info spi_board_info[] = {
+ {
+ .modalias     = "max3100",
+ .platform_data        = &max3100_plat_data,
+ .irq          = IRQ_EINT12,
+ .max_speed_hz = 5*1000*1000,
+ .chip_select  = 0,
+ },
+ };
+
+ * The initial minor number is 209 in the low-density serial port:
+ * mknod /dev/ttyMAX0 c 204 209
+ */
+
+#define MAX3100_MAJOR 204
+#define MAX3100_MINOR 209
+/* 4 MAX3100s should be enough for everyone */
+#define MAX_MAX3100 4
+
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/spi/spi.h>
+#include <linux/freezer.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+#include <linux/serial_max3100.h>
+
+#define MAX3100_C    (1<<14)
+#define MAX3100_D    (0<<14)
+#define MAX3100_W    (1<<15)
+#define MAX3100_RX   (0<<15)
+
+#define MAX3100_WC   (MAX3100_W  | MAX3100_C)
+#define MAX3100_RC   (MAX3100_RX | MAX3100_C)
+#define MAX3100_WD   (MAX3100_W  | MAX3100_D)
+#define MAX3100_RD   (MAX3100_RX | MAX3100_D)
+#define MAX3100_CMD  (3 << 14)
+
+#define MAX3100_T    (1<<14)
+#define MAX3100_R    (1<<15)
+
+#define MAX3100_FEN  (1<<13)
+#define MAX3100_SHDN (1<<12)
+#define MAX3100_TM   (1<<11)
+#define MAX3100_RM   (1<<10)
+#define MAX3100_PM   (1<<9)
+#define MAX3100_RAM  (1<<8)
+#define MAX3100_IR   (1<<7)
+#define MAX3100_ST   (1<<6)
+#define MAX3100_PE   (1<<5)
+#define MAX3100_L    (1<<4)
+#define MAX3100_BAUD (0xf)
+
+#define MAX3100_TE   (1<<10)
+#define MAX3100_RAFE (1<<10)
+#define MAX3100_RTS  (1<<9)
+#define MAX3100_CTS  (1<<9)
+#define MAX3100_PT   (1<<8)
+#define MAX3100_DATA (0xff)
+
+#define MAX3100_RT   (MAX3100_R | MAX3100_T)
+#define MAX3100_RTC  (MAX3100_RT | MAX3100_CTS | MAX3100_RAFE)
+
+/* the following simulate a status reg for ignore_status_mask */
+#define MAX3100_STATUS_PE 1
+#define MAX3100_STATUS_FE 2
+#define MAX3100_STATUS_OE 4
+
+struct max3100_port {
+       struct uart_port port;
+       struct spi_device *spi;
+
+       int cts;                /* last CTS received for flow ctrl */
+       int tx_empty;           /* last TX empty bit */
+
+       spinlock_t conf_lock;   /* shared data */
+       int conf_commit;        /* need to make changes */
+       int conf;               /* configuration for the MAX31000
+                                * (bits 0-7, bits 8-11 are irqs) */
+       int rts_commit;         /* need to change rts */
+       int rts;                /* rts status */
+       int baud;               /* current baud rate */
+
+       int parity;             /* keeps track if we should send parity */
+#define MAX3100_PARITY_ON 1
+#define MAX3100_PARITY_ODD 2
+#define MAX3100_7BIT 4
+       int rx_enabled;         /* if we should rx chars */
+
+       int irq;                /* irq assigned to the max3100 */
+
+       int minor;              /* minor number */
+       int crystal;            /* 1 if 3.6864Mhz crystal 0 for 1.8432 */
+       int loopback;           /* 1 if we are in loopback mode */
+
+       /* for handling irqs: need workqueue since we do spi_sync */
+       struct workqueue_struct *workqueue;
+       struct work_struct work;
+       /* set to 1 to make the workhandler exit as soon as possible */
+       int  force_end_work;
+       /* need to know we are suspending to avoid deadlock on workqueue */
+       int suspending;
+
+       /* hook for suspending MAX3100 via dedicated pin */
+       void (*max3100_hw_suspend) (int suspend);
+
+       /* poll time (in ms) for ctrl lines */
+       int poll_time;
+       /* and its timer */
+       struct timer_list       timer;
+};
+
+static struct max3100_port *max3100s[MAX_MAX3100]; /* the chips */
+static DEFINE_MUTEX(max3100s_lock);               /* race on probe */
+
+static int max3100_do_parity(struct max3100_port *s, u16 c)
+{
+       int parity;
+
+       if (s->parity & MAX3100_PARITY_ODD)
+               parity = 1;
+       else
+               parity = 0;
+
+       if (s->parity & MAX3100_7BIT)
+               c &= 0x7f;
+       else
+               c &= 0xff;
+
+       parity = parity ^ (hweight8(c) & 1);
+       return parity;
+}
+
+static int max3100_check_parity(struct max3100_port *s, u16 c)
+{
+       return max3100_do_parity(s, c) == ((c >> 8) & 1);
+}
+
+static void max3100_calc_parity(struct max3100_port *s, u16 *c)
+{
+       if (s->parity & MAX3100_7BIT)
+               *c &= 0x7f;
+       else
+               *c &= 0xff;
+
+       if (s->parity & MAX3100_PARITY_ON)
+               *c |= max3100_do_parity(s, *c) << 8;
+}
+
+static void max3100_work(struct work_struct *w);
+
+static void max3100_dowork(struct max3100_port *s)
+{
+       if (!s->force_end_work && !freezing(current) && !s->suspending)
+               queue_work(s->workqueue, &s->work);
+}
+
+static void max3100_timeout(unsigned long data)
+{
+       struct max3100_port *s = (struct max3100_port *)data;
+
+       if (s->port.state) {
+               max3100_dowork(s);
+               mod_timer(&s->timer, jiffies + s->poll_time);
+       }
+}
+
+static int max3100_sr(struct max3100_port *s, u16 tx, u16 *rx)
+{
+       struct spi_message message;
+       u16 etx, erx;
+       int status;
+       struct spi_transfer tran = {
+               .tx_buf = &etx,
+               .rx_buf = &erx,
+               .len = 2,
+       };
+
+       etx = cpu_to_be16(tx);
+       spi_message_init(&message);
+       spi_message_add_tail(&tran, &message);
+       status = spi_sync(s->spi, &message);
+       if (status) {
+               dev_warn(&s->spi->dev, "error while calling spi_sync\n");
+               return -EIO;
+       }
+       *rx = be16_to_cpu(erx);
+       s->tx_empty = (*rx & MAX3100_T) > 0;
+       dev_dbg(&s->spi->dev, "%04x - %04x\n", tx, *rx);
+       return 0;
+}
+
+static int max3100_handlerx(struct max3100_port *s, u16 rx)
+{
+       unsigned int ch, flg, status = 0;
+       int ret = 0, cts;
+
+       if (rx & MAX3100_R && s->rx_enabled) {
+               dev_dbg(&s->spi->dev, "%s\n", __func__);
+               ch = rx & (s->parity & MAX3100_7BIT ? 0x7f : 0xff);
+               if (rx & MAX3100_RAFE) {
+                       s->port.icount.frame++;
+                       flg = TTY_FRAME;
+                       status |= MAX3100_STATUS_FE;
+               } else {
+                       if (s->parity & MAX3100_PARITY_ON) {
+                               if (max3100_check_parity(s, rx)) {
+                                       s->port.icount.rx++;
+                                       flg = TTY_NORMAL;
+                               } else {
+                                       s->port.icount.parity++;
+                                       flg = TTY_PARITY;
+                                       status |= MAX3100_STATUS_PE;
+                               }
+                       } else {
+                               s->port.icount.rx++;
+                               flg = TTY_NORMAL;
+                       }
+               }
+               uart_insert_char(&s->port, status, MAX3100_STATUS_OE, ch, flg);
+               ret = 1;
+       }
+
+       cts = (rx & MAX3100_CTS) > 0;
+       if (s->cts != cts) {
+               s->cts = cts;
+               uart_handle_cts_change(&s->port, cts ? TIOCM_CTS : 0);
+       }
+
+       return ret;
+}
+
+static void max3100_work(struct work_struct *w)
+{
+       struct max3100_port *s = container_of(w, struct max3100_port, work);
+       int rxchars;
+       u16 tx, rx;
+       int conf, cconf, rts, crts;
+       struct circ_buf *xmit = &s->port.state->xmit;
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       rxchars = 0;
+       do {
+               spin_lock(&s->conf_lock);
+               conf = s->conf;
+               cconf = s->conf_commit;
+               s->conf_commit = 0;
+               rts = s->rts;
+               crts = s->rts_commit;
+               s->rts_commit = 0;
+               spin_unlock(&s->conf_lock);
+               if (cconf)
+                       max3100_sr(s, MAX3100_WC | conf, &rx);
+               if (crts) {
+                       max3100_sr(s, MAX3100_WD | MAX3100_TE |
+                                  (s->rts ? MAX3100_RTS : 0), &rx);
+                       rxchars += max3100_handlerx(s, rx);
+               }
+
+               max3100_sr(s, MAX3100_RD, &rx);
+               rxchars += max3100_handlerx(s, rx);
+
+               if (rx & MAX3100_T) {
+                       tx = 0xffff;
+                       if (s->port.x_char) {
+                               tx = s->port.x_char;
+                               s->port.icount.tx++;
+                               s->port.x_char = 0;
+                       } else if (!uart_circ_empty(xmit) &&
+                                  !uart_tx_stopped(&s->port)) {
+                               tx = xmit->buf[xmit->tail];
+                               xmit->tail = (xmit->tail + 1) &
+                                       (UART_XMIT_SIZE - 1);
+                               s->port.icount.tx++;
+                       }
+                       if (tx != 0xffff) {
+                               max3100_calc_parity(s, &tx);
+                               tx |= MAX3100_WD | (s->rts ? MAX3100_RTS : 0);
+                               max3100_sr(s, tx, &rx);
+                               rxchars += max3100_handlerx(s, rx);
+                       }
+               }
+
+               if (rxchars > 16) {
+                       tty_flip_buffer_push(&s->port.state->port);
+                       rxchars = 0;
+               }
+               if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+                       uart_write_wakeup(&s->port);
+
+       } while (!s->force_end_work &&
+                !freezing(current) &&
+                ((rx & MAX3100_R) ||
+                 (!uart_circ_empty(xmit) &&
+                  !uart_tx_stopped(&s->port))));
+
+       if (rxchars > 0)
+               tty_flip_buffer_push(&s->port.state->port);
+}
+
+static irqreturn_t max3100_irq(int irqno, void *dev_id)
+{
+       struct max3100_port *s = dev_id;
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       max3100_dowork(s);
+       return IRQ_HANDLED;
+}
+
+static void max3100_enable_ms(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       if (s->poll_time > 0)
+               mod_timer(&s->timer, jiffies);
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+}
+
+static void max3100_start_tx(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       max3100_dowork(s);
+}
+
+static void max3100_stop_rx(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       s->rx_enabled = 0;
+       spin_lock(&s->conf_lock);
+       s->conf &= ~MAX3100_RM;
+       s->conf_commit = 1;
+       spin_unlock(&s->conf_lock);
+       max3100_dowork(s);
+}
+
+static unsigned int max3100_tx_empty(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       /* may not be truly up-to-date */
+       max3100_dowork(s);
+       return s->tx_empty;
+}
+
+static unsigned int max3100_get_mctrl(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       /* may not be truly up-to-date */
+       max3100_dowork(s);
+       /* always assert DCD and DSR since these lines are not wired */
+       return (s->cts ? TIOCM_CTS : 0) | TIOCM_DSR | TIOCM_CAR;
+}
+
+static void max3100_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+       int rts;
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       rts = (mctrl & TIOCM_RTS) > 0;
+
+       spin_lock(&s->conf_lock);
+       if (s->rts != rts) {
+               s->rts = rts;
+               s->rts_commit = 1;
+               max3100_dowork(s);
+       }
+       spin_unlock(&s->conf_lock);
+}
+
+static void
+max3100_set_termios(struct uart_port *port, struct ktermios *termios,
+                   struct ktermios *old)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+       int baud = 0;
+       unsigned cflag;
+       u32 param_new, param_mask, parity = 0;
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       cflag = termios->c_cflag;
+       param_new = 0;
+       param_mask = 0;
+
+       baud = tty_termios_baud_rate(termios);
+       param_new = s->conf & MAX3100_BAUD;
+       switch (baud) {
+       case 300:
+               if (s->crystal)
+                       baud = s->baud;
+               else
+                       param_new = 15;
+               break;
+       case 600:
+               param_new = 14 + s->crystal;
+               break;
+       case 1200:
+               param_new = 13 + s->crystal;
+               break;
+       case 2400:
+               param_new = 12 + s->crystal;
+               break;
+       case 4800:
+               param_new = 11 + s->crystal;
+               break;
+       case 9600:
+               param_new = 10 + s->crystal;
+               break;
+       case 19200:
+               param_new = 9 + s->crystal;
+               break;
+       case 38400:
+               param_new = 8 + s->crystal;
+               break;
+       case 57600:
+               param_new = 1 + s->crystal;
+               break;
+       case 115200:
+               param_new = 0 + s->crystal;
+               break;
+       case 230400:
+               if (s->crystal)
+                       param_new = 0;
+               else
+                       baud = s->baud;
+               break;
+       default:
+               baud = s->baud;
+       }
+       tty_termios_encode_baud_rate(termios, baud, baud);
+       s->baud = baud;
+       param_mask |= MAX3100_BAUD;
+
+       if ((cflag & CSIZE) == CS8) {
+               param_new &= ~MAX3100_L;
+               parity &= ~MAX3100_7BIT;
+       } else {
+               param_new |= MAX3100_L;
+               parity |= MAX3100_7BIT;
+               cflag = (cflag & ~CSIZE) | CS7;
+       }
+       param_mask |= MAX3100_L;
+
+       if (cflag & CSTOPB)
+               param_new |= MAX3100_ST;
+       else
+               param_new &= ~MAX3100_ST;
+       param_mask |= MAX3100_ST;
+
+       if (cflag & PARENB) {
+               param_new |= MAX3100_PE;
+               parity |= MAX3100_PARITY_ON;
+       } else {
+               param_new &= ~MAX3100_PE;
+               parity &= ~MAX3100_PARITY_ON;
+       }
+       param_mask |= MAX3100_PE;
+
+       if (cflag & PARODD)
+               parity |= MAX3100_PARITY_ODD;
+       else
+               parity &= ~MAX3100_PARITY_ODD;
+
+       /* mask termios capabilities we don't support */
+       cflag &= ~CMSPAR;
+       termios->c_cflag = cflag;
+
+       s->port.ignore_status_mask = 0;
+       if (termios->c_iflag & IGNPAR)
+               s->port.ignore_status_mask |=
+                       MAX3100_STATUS_PE | MAX3100_STATUS_FE |
+                       MAX3100_STATUS_OE;
+
+       /* we are sending char from a workqueue so enable */
+       s->port.state->port.low_latency = 1;
+
+       if (s->poll_time > 0)
+               del_timer_sync(&s->timer);
+
+       uart_update_timeout(port, termios->c_cflag, baud);
+
+       spin_lock(&s->conf_lock);
+       s->conf = (s->conf & ~param_mask) | (param_new & param_mask);
+       s->conf_commit = 1;
+       s->parity = parity;
+       spin_unlock(&s->conf_lock);
+       max3100_dowork(s);
+
+       if (UART_ENABLE_MS(&s->port, termios->c_cflag))
+               max3100_enable_ms(&s->port);
+}
+
+static void max3100_shutdown(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       if (s->suspending)
+               return;
+
+       s->force_end_work = 1;
+
+       if (s->poll_time > 0)
+               del_timer_sync(&s->timer);
+
+       if (s->workqueue) {
+               flush_workqueue(s->workqueue);
+               destroy_workqueue(s->workqueue);
+               s->workqueue = NULL;
+       }
+       if (s->irq)
+               free_irq(s->irq, s);
+
+       /* set shutdown mode to save power */
+       if (s->max3100_hw_suspend)
+               s->max3100_hw_suspend(1);
+       else  {
+               u16 tx, rx;
+
+               tx = MAX3100_WC | MAX3100_SHDN;
+               max3100_sr(s, tx, &rx);
+       }
+}
+
+static int max3100_startup(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+       char b[12];
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       s->conf = MAX3100_RM;
+       s->baud = s->crystal ? 230400 : 115200;
+       s->rx_enabled = 1;
+
+       if (s->suspending)
+               return 0;
+
+       s->force_end_work = 0;
+       s->parity = 0;
+       s->rts = 0;
+
+       sprintf(b, "max3100-%d", s->minor);
+       s->workqueue = create_freezable_workqueue(b);
+       if (!s->workqueue) {
+               dev_warn(&s->spi->dev, "cannot create workqueue\n");
+               return -EBUSY;
+       }
+       INIT_WORK(&s->work, max3100_work);
+
+       if (request_irq(s->irq, max3100_irq,
+                       IRQF_TRIGGER_FALLING, "max3100", s) < 0) {
+               dev_warn(&s->spi->dev, "cannot allocate irq %d\n", s->irq);
+               s->irq = 0;
+               destroy_workqueue(s->workqueue);
+               s->workqueue = NULL;
+               return -EBUSY;
+       }
+
+       if (s->loopback) {
+               u16 tx, rx;
+               tx = 0x4001;
+               max3100_sr(s, tx, &rx);
+       }
+
+       if (s->max3100_hw_suspend)
+               s->max3100_hw_suspend(0);
+       s->conf_commit = 1;
+       max3100_dowork(s);
+       /* wait for clock to settle */
+       msleep(50);
+
+       max3100_enable_ms(&s->port);
+
+       return 0;
+}
+
+static const char *max3100_type(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       return s->port.type == PORT_MAX3100 ? "MAX3100" : NULL;
+}
+
+static void max3100_release_port(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+}
+
+static void max3100_config_port(struct uart_port *port, int flags)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       if (flags & UART_CONFIG_TYPE)
+               s->port.type = PORT_MAX3100;
+}
+
+static int max3100_verify_port(struct uart_port *port,
+                              struct serial_struct *ser)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+       int ret = -EINVAL;
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       if (ser->type == PORT_UNKNOWN || ser->type == PORT_MAX3100)
+               ret = 0;
+       return ret;
+}
+
+static void max3100_stop_tx(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+}
+
+static int max3100_request_port(struct uart_port *port)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+       return 0;
+}
+
+static void max3100_break_ctl(struct uart_port *port, int break_state)
+{
+       struct max3100_port *s = container_of(port,
+                                             struct max3100_port,
+                                             port);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+}
+
+static struct uart_ops max3100_ops = {
+       .tx_empty       = max3100_tx_empty,
+       .set_mctrl      = max3100_set_mctrl,
+       .get_mctrl      = max3100_get_mctrl,
+       .stop_tx        = max3100_stop_tx,
+       .start_tx       = max3100_start_tx,
+       .stop_rx        = max3100_stop_rx,
+       .enable_ms      = max3100_enable_ms,
+       .break_ctl      = max3100_break_ctl,
+       .startup        = max3100_startup,
+       .shutdown       = max3100_shutdown,
+       .set_termios    = max3100_set_termios,
+       .type           = max3100_type,
+       .release_port   = max3100_release_port,
+       .request_port   = max3100_request_port,
+       .config_port    = max3100_config_port,
+       .verify_port    = max3100_verify_port,
+};
+
+static struct uart_driver max3100_uart_driver = {
+       .owner          = THIS_MODULE,
+       .driver_name    = "ttyMAX",
+       .dev_name       = "ttyMAX",
+       .major          = MAX3100_MAJOR,
+       .minor          = MAX3100_MINOR,
+       .nr             = MAX_MAX3100,
+};
+static int uart_driver_registered;
+
+static int max3100_probe(struct spi_device *spi)
+{
+       int i, retval;
+       struct plat_max3100 *pdata;
+       u16 tx, rx;
+
+       mutex_lock(&max3100s_lock);
+
+       if (!uart_driver_registered) {
+               uart_driver_registered = 1;
+               retval = uart_register_driver(&max3100_uart_driver);
+               if (retval) {
+                       printk(KERN_ERR "Couldn't register max3100 uart driver\n");
+                       mutex_unlock(&max3100s_lock);
+                       return retval;
+               }
+       }
+
+       for (i = 0; i < MAX_MAX3100; i++)
+               if (!max3100s[i])
+                       break;
+       if (i == MAX_MAX3100) {
+               dev_warn(&spi->dev, "too many MAX3100 chips\n");
+               mutex_unlock(&max3100s_lock);
+               return -ENOMEM;
+       }
+
+       max3100s[i] = kzalloc(sizeof(struct max3100_port), GFP_KERNEL);
+       if (!max3100s[i]) {
+               dev_warn(&spi->dev,
+                        "kmalloc for max3100 structure %d failed!\n", i);
+               mutex_unlock(&max3100s_lock);
+               return -ENOMEM;
+       }
+       max3100s[i]->spi = spi;
+       max3100s[i]->irq = spi->irq;
+       spin_lock_init(&max3100s[i]->conf_lock);
+       spi_set_drvdata(spi, max3100s[i]);
+       pdata = dev_get_platdata(&spi->dev);
+       max3100s[i]->crystal = pdata->crystal;
+       max3100s[i]->loopback = pdata->loopback;
+       max3100s[i]->poll_time = msecs_to_jiffies(pdata->poll_time);
+       if (pdata->poll_time > 0 && max3100s[i]->poll_time == 0)
+               max3100s[i]->poll_time = 1;
+       max3100s[i]->max3100_hw_suspend = pdata->max3100_hw_suspend;
+       max3100s[i]->minor = i;
+       init_timer(&max3100s[i]->timer);
+       max3100s[i]->timer.function = max3100_timeout;
+       max3100s[i]->timer.data = (unsigned long) max3100s[i];
+
+       dev_dbg(&spi->dev, "%s: adding port %d\n", __func__, i);
+       max3100s[i]->port.irq = max3100s[i]->irq;
+       max3100s[i]->port.uartclk = max3100s[i]->crystal ? 3686400 : 1843200;
+       max3100s[i]->port.fifosize = 16;
+       max3100s[i]->port.ops = &max3100_ops;
+       max3100s[i]->port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
+       max3100s[i]->port.line = i;
+       max3100s[i]->port.type = PORT_MAX3100;
+       max3100s[i]->port.dev = &spi->dev;
+       retval = uart_add_one_port(&max3100_uart_driver, &max3100s[i]->port);
+       if (retval < 0)
+               dev_warn(&spi->dev,
+                        "uart_add_one_port failed for line %d with error %d\n",
+                        i, retval);
+
+       /* set shutdown mode to save power. Will be woken-up on open */
+       if (max3100s[i]->max3100_hw_suspend)
+               max3100s[i]->max3100_hw_suspend(1);
+       else {
+               tx = MAX3100_WC | MAX3100_SHDN;
+               max3100_sr(max3100s[i], tx, &rx);
+       }
+       mutex_unlock(&max3100s_lock);
+       return 0;
+}
+
+static int max3100_remove(struct spi_device *spi)
+{
+       struct max3100_port *s = spi_get_drvdata(spi);
+       int i;
+
+       mutex_lock(&max3100s_lock);
+
+       /* find out the index for the chip we are removing */
+       for (i = 0; i < MAX_MAX3100; i++)
+               if (max3100s[i] == s) {
+                       dev_dbg(&spi->dev, "%s: removing port %d\n", __func__, i);
+                       uart_remove_one_port(&max3100_uart_driver, &max3100s[i]->port);
+                       kfree(max3100s[i]);
+                       max3100s[i] = NULL;
+                       break;
+               }
+
+       WARN_ON(i == MAX_MAX3100);
+       
+       /* check if this is the last chip we have */
+       for (i = 0; i < MAX_MAX3100; i++)
+               if (max3100s[i]) {
+                       mutex_unlock(&max3100s_lock);
+                       return 0;
+               }
+       pr_debug("removing max3100 driver\n");
+       uart_unregister_driver(&max3100_uart_driver);
+
+       mutex_unlock(&max3100s_lock);
+       return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+
+static int max3100_suspend(struct device *dev)
+{
+       struct max3100_port *s = dev_get_drvdata(dev);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       disable_irq(s->irq);
+
+       s->suspending = 1;
+       uart_suspend_port(&max3100_uart_driver, &s->port);
+
+       if (s->max3100_hw_suspend)
+               s->max3100_hw_suspend(1);
+       else {
+               /* no HW suspend, so do SW one */
+               u16 tx, rx;
+
+               tx = MAX3100_WC | MAX3100_SHDN;
+               max3100_sr(s, tx, &rx);
+       }
+       return 0;
+}
+
+static int max3100_resume(struct device *dev)
+{
+       struct max3100_port *s = dev_get_drvdata(dev);
+
+       dev_dbg(&s->spi->dev, "%s\n", __func__);
+
+       if (s->max3100_hw_suspend)
+               s->max3100_hw_suspend(0);
+       uart_resume_port(&max3100_uart_driver, &s->port);
+       s->suspending = 0;
+
+       enable_irq(s->irq);
+
+       s->conf_commit = 1;
+       if (s->workqueue)
+               max3100_dowork(s);
+
+       return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(max3100_pm_ops, max3100_suspend, max3100_resume);
+#define MAX3100_PM_OPS (&max3100_pm_ops)
+
+#else
+#define MAX3100_PM_OPS NULL
+#endif
+
+static struct spi_driver max3100_driver = {
+       .driver = {
+               .name           = "max3100",
+               .owner          = THIS_MODULE,
+               .pm             = MAX3100_PM_OPS,
+       },
+       .probe          = max3100_probe,
+       .remove         = max3100_remove,
+};
+
+module_spi_driver(max3100_driver);
+
+MODULE_DESCRIPTION("MAX3100 driver");
+MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:max3100");