USB: serial: add Fintek F81232 usb to serial driver

This is the first cut at a driver for the Fintek F81232 USB to serial
single port converter.  This provides the initial framework for the
device, and some data can move through it, but no line settings are
handled, so it's not that useful yet.  It does give people a starting
place to work from.

Thank to Fintek for providing samples and specifications, without which,
this driver would have never been able to be written.

Cc: Amanda Ying <Amanda_Ying@fintek.com.tw>
Cc: Tom Tsai <Tom_Tsai@fintek.com.tw>
Cc: <linux-usb@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/Kconfig

@@ -238,6 +238,15 @@ config USB_SERIAL_EDGEPORT_TI
 	  To compile this driver as a module, choose M here: the
 	  module will be called io_ti.
 
+config USB_SERIAL_F81232
+	tristate "USB Fintek F81232 Single Port Serial Driver"
+	help
+	  Say Y here if you want to use the Fintek F81232 single
+	  port usb to serial adapter.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called f81232.
+
 config USB_SERIAL_GARMIN
        tristate "USB Garmin GPS driver"
        help

drivers/usb/serial/Makefile

@@ -23,6 +23,7 @@ obj-$(CONFIG_USB_SERIAL_DIGI_ACCELEPORT)	+= digi_acceleport.o
 obj-$(CONFIG_USB_SERIAL_EDGEPORT)		+= io_edgeport.o
 obj-$(CONFIG_USB_SERIAL_EDGEPORT_TI)		+= io_ti.o
 obj-$(CONFIG_USB_SERIAL_EMPEG)			+= empeg.o
+obj-$(CONFIG_USB_SERIAL_F81232)			+= f81232.o
 obj-$(CONFIG_USB_SERIAL_FTDI_SIO)		+= ftdi_sio.o
 obj-$(CONFIG_USB_SERIAL_FUNSOFT)		+= funsoft.o
 obj-$(CONFIG_USB_SERIAL_GARMIN)			+= garmin_gps.o

drivers/usb/serial/f81232.c

@@ -0,0 +1,405 @@
+/*
+ * Fintek F81232 USB to serial adaptor driver
+ *
+ * Copyright (C) 2012 Greg Kroah-Hartman (gregkh@linuxfoundation.org)
+ * Copyright (C) 2012 Linux Foundation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/serial.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+
+static bool debug;
+
+static const struct usb_device_id id_table[] = {
+	{ USB_DEVICE(0x1934, 0x0706) },
+	{ }					/* Terminating entry */
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+#define CONTROL_DTR			0x01
+#define CONTROL_RTS			0x02
+
+#define UART_STATE			0x08
+#define UART_STATE_TRANSIENT_MASK	0x74
+#define UART_DCD			0x01
+#define UART_DSR			0x02
+#define UART_BREAK_ERROR		0x04
+#define UART_RING			0x08
+#define UART_FRAME_ERROR		0x10
+#define UART_PARITY_ERROR		0x20
+#define UART_OVERRUN_ERROR		0x40
+#define UART_CTS			0x80
+
+struct f81232_private {
+	spinlock_t lock;
+	wait_queue_head_t delta_msr_wait;
+	u8 line_control;
+	u8 line_status;
+};
+
+static void f81232_update_line_status(struct usb_serial_port *port,
+				      unsigned char *data,
+				      unsigned int actual_length)
+{
+}
+
+static void f81232_read_int_callback(struct urb *urb)
+{
+	struct usb_serial_port *port =  urb->context;
+	unsigned char *data = urb->transfer_buffer;
+	unsigned int actual_length = urb->actual_length;
+	int status = urb->status;
+	int retval;
+
+	dbg("%s (%d)", __func__, port->number);
+
+	switch (status) {
+	case 0:
+		/* success */
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		/* this urb is terminated, clean up */
+		dbg("%s - urb shutting down with status: %d", __func__,
+		    status);
+		return;
+	default:
+		dbg("%s - nonzero urb status received: %d", __func__,
+		    status);
+		goto exit;
+	}
+
+	usb_serial_debug_data(debug, &port->dev, __func__,
+			      urb->actual_length, urb->transfer_buffer);
+
+	f81232_update_line_status(port, data, actual_length);
+
+exit:
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval)
+		dev_err(&urb->dev->dev,
+			"%s - usb_submit_urb failed with result %d\n",
+			__func__, retval);
+}
+
+static void f81232_process_read_urb(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+	struct f81232_private *priv = usb_get_serial_port_data(port);
+	struct tty_struct *tty;
+	unsigned char *data = urb->transfer_buffer;
+	char tty_flag = TTY_NORMAL;
+	unsigned long flags;
+	u8 line_status;
+	int i;
+
+	/* update line status */
+	spin_lock_irqsave(&priv->lock, flags);
+	line_status = priv->line_status;
+	priv->line_status &= ~UART_STATE_TRANSIENT_MASK;
+	spin_unlock_irqrestore(&priv->lock, flags);
+	wake_up_interruptible(&priv->delta_msr_wait);
+
+	if (!urb->actual_length)
+		return;
+
+	tty = tty_port_tty_get(&port->port);
+	if (!tty)
+		return;
+
+	/* break takes precedence over parity, */
+	/* which takes precedence over framing errors */
+	if (line_status & UART_BREAK_ERROR)
+		tty_flag = TTY_BREAK;
+	else if (line_status & UART_PARITY_ERROR)
+		tty_flag = TTY_PARITY;
+	else if (line_status & UART_FRAME_ERROR)
+		tty_flag = TTY_FRAME;
+	dbg("%s - tty_flag = %d", __func__, tty_flag);
+
+	/* overrun is special, not associated with a char */
+	if (line_status & UART_OVERRUN_ERROR)
+		tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+
+	if (port->port.console && port->sysrq) {
+		for (i = 0; i < urb->actual_length; ++i)
+			if (!usb_serial_handle_sysrq_char(port, data[i]))
+				tty_insert_flip_char(tty, data[i], tty_flag);
+	} else {
+		tty_insert_flip_string_fixed_flag(tty, data, tty_flag,
+							urb->actual_length);
+	}
+
+	tty_flip_buffer_push(tty);
+	tty_kref_put(tty);
+}
+
+static int set_control_lines(struct usb_device *dev, u8 value)
+{
+	/* FIXME - Stubbed out for now */
+	return 0;
+}
+
+static void f81232_break_ctl(struct tty_struct *tty, int break_state)
+{
+	/* FIXME - Stubbed out for now */
+
+	/*
+	 * break_state = -1 to turn on break, and 0 to turn off break
+	 * see drivers/char/tty_io.c to see it used.
+	 * last_set_data_urb_value NEVER has the break bit set in it.
+	 */
+}
+
+static void f81232_set_termios(struct tty_struct *tty,
+		struct usb_serial_port *port, struct ktermios *old_termios)
+{
+	/* FIXME - Stubbed out for now */
+
+	/* Don't change anything if nothing has changed */
+	if (!tty_termios_hw_change(tty->termios, old_termios))
+		return;
+
+	/* Do the real work here... */
+}
+
+static int f81232_tiocmget(struct tty_struct *tty)
+{
+	/* FIXME - Stubbed out for now */
+	return 0;
+}
+
+static int f81232_tiocmset(struct tty_struct *tty,
+			unsigned int set, unsigned int clear)
+{
+	/* FIXME - Stubbed out for now */
+	return 0;
+}
+
+static int f81232_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+	struct ktermios tmp_termios;
+	int result;
+
+	/* Setup termios */
+	if (tty)
+		f81232_set_termios(tty, port, &tmp_termios);
+
+	dbg("%s - submitting interrupt urb", __func__);
+	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
+	if (result) {
+		dev_err(&port->dev, "%s - failed submitting interrupt urb,"
+			" error %d\n", __func__, result);
+		return result;
+	}
+
+	result = usb_serial_generic_open(tty, port);
+	if (result) {
+		usb_kill_urb(port->interrupt_in_urb);
+		return result;
+	}
+
+	port->port.drain_delay = 256;
+	return 0;
+}
+
+static void f81232_close(struct usb_serial_port *port)
+{
+	usb_serial_generic_close(port);
+	usb_kill_urb(port->interrupt_in_urb);
+}
+
+static void f81232_dtr_rts(struct usb_serial_port *port, int on)
+{
+	struct f81232_private *priv = usb_get_serial_port_data(port);
+	unsigned long flags;
+	u8 control;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	/* Change DTR and RTS */
+	if (on)
+		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
+	else
+		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
+	control = priv->line_control;
+	spin_unlock_irqrestore(&priv->lock, flags);
+	set_control_lines(port->serial->dev, control);
+}
+
+static int f81232_carrier_raised(struct usb_serial_port *port)
+{
+	struct f81232_private *priv = usb_get_serial_port_data(port);
+	if (priv->line_status & UART_DCD)
+		return 1;
+	return 0;
+}
+
+static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
+{
+	struct f81232_private *priv = usb_get_serial_port_data(port);
+	unsigned long flags;
+	unsigned int prevstatus;
+	unsigned int status;
+	unsigned int changed;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	prevstatus = priv->line_status;
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	while (1) {
+		interruptible_sleep_on(&priv->delta_msr_wait);
+		/* see if a signal did it */
+		if (signal_pending(current))
+			return -ERESTARTSYS;
+
+		spin_lock_irqsave(&priv->lock, flags);
+		status = priv->line_status;
+		spin_unlock_irqrestore(&priv->lock, flags);
+
+		changed = prevstatus ^ status;
+
+		if (((arg & TIOCM_RNG) && (changed & UART_RING)) ||
+		    ((arg & TIOCM_DSR) && (changed & UART_DSR)) ||
+		    ((arg & TIOCM_CD)  && (changed & UART_DCD)) ||
+		    ((arg & TIOCM_CTS) && (changed & UART_CTS))) {
+			return 0;
+		}
+		prevstatus = status;
+	}
+	/* NOTREACHED */
+	return 0;
+}
+
+static int f81232_ioctl(struct tty_struct *tty,
+			unsigned int cmd, unsigned long arg)
+{
+	struct serial_struct ser;
+	struct usb_serial_port *port = tty->driver_data;
+	dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
+
+	switch (cmd) {
+	case TIOCGSERIAL:
+		memset(&ser, 0, sizeof ser);
+		ser.type = PORT_16654;
+		ser.line = port->serial->minor;
+		ser.port = port->number;
+		ser.baud_base = 460800;
+
+		if (copy_to_user((void __user *)arg, &ser, sizeof ser))
+			return -EFAULT;
+
+		return 0;
+
+	case TIOCMIWAIT:
+		dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);
+		return wait_modem_info(port, arg);
+	default:
+		dbg("%s not supported = 0x%04x", __func__, cmd);
+		break;
+	}
+	return -ENOIOCTLCMD;
+}
+
+static int f81232_startup(struct usb_serial *serial)
+{
+	struct f81232_private *priv;
+	int i;
+
+	for (i = 0; i < serial->num_ports; ++i) {
+		priv = kzalloc(sizeof(struct f81232_private), GFP_KERNEL);
+		if (!priv)
+			goto cleanup;
+		spin_lock_init(&priv->lock);
+		init_waitqueue_head(&priv->delta_msr_wait);
+		usb_set_serial_port_data(serial->port[i], priv);
+	}
+	return 0;
+
+cleanup:
+	for (--i; i >= 0; --i) {
+		priv = usb_get_serial_port_data(serial->port[i]);
+		kfree(priv);
+		usb_set_serial_port_data(serial->port[i], NULL);
+	}
+	return -ENOMEM;
+}
+
+static void f81232_release(struct usb_serial *serial)
+{
+	int i;
+	struct f81232_private *priv;
+
+	for (i = 0; i < serial->num_ports; ++i) {
+		priv = usb_get_serial_port_data(serial->port[i]);
+		kfree(priv);
+	}
+}
+
+static struct usb_driver f81232_driver = {
+	.name =		"f81232",
+	.probe =	usb_serial_probe,
+	.disconnect =	usb_serial_disconnect,
+	.id_table =	id_table,
+	.suspend =      usb_serial_suspend,
+	.resume =       usb_serial_resume,
+	.no_dynamic_id = 	1,
+	.supports_autosuspend =	1,
+};
+
+static struct usb_serial_driver f81232_device = {
+	.driver = {
+		.owner =	THIS_MODULE,
+		.name =		"f81232",
+	},
+	.id_table =		id_table,
+	.usb_driver = 		&f81232_driver,
+	.num_ports =		1,
+	.bulk_in_size =		256,
+	.bulk_out_size =	256,
+	.open =			f81232_open,
+	.close =		f81232_close,
+	.dtr_rts = 		f81232_dtr_rts,
+	.carrier_raised =	f81232_carrier_raised,
+	.ioctl =		f81232_ioctl,
+	.break_ctl =		f81232_break_ctl,
+	.set_termios =		f81232_set_termios,
+	.tiocmget =		f81232_tiocmget,
+	.tiocmset =		f81232_tiocmset,
+	.process_read_urb =	f81232_process_read_urb,
+	.read_int_callback =	f81232_read_int_callback,
+	.attach =		f81232_startup,
+	.release =		f81232_release,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+	&f81232_device,
+	NULL,
+};
+
+module_usb_serial_driver(f81232_driver, serial_drivers);
+
+MODULE_DESCRIPTION("Fintek F81232 USB to serial adaptor driver");
+MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org");
+MODULE_LICENSE("GPL v2");
+
+module_param(debug, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Debug enabled or not");
+