[mirror_ubuntu-bionic-kernel.git] / drivers / usb / serial / ch341.c

/*
 * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
 * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
 * Copyright 2009, Boris Hajduk <boris@hajduk.org>
 *
 * ch341.c implements a serial port driver for the Winchiphead CH341.
 *
 * The CH341 device can be used to implement an RS232 asynchronous
 * serial port, an IEEE-1284 parallel printer port or a memory-like
 * interface. In all cases the CH341 supports an I2C interface as well.
 * This driver only supports the asynchronous serial interface.
 *
 * 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/init.h>
#include <linux/tty.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/serial.h>
#include <asm/unaligned.h>

#define DEFAULT_BAUD_RATE 9600
#define DEFAULT_TIMEOUT   1000

/* flags for IO-Bits */
#define CH341_BIT_RTS (1 << 6)
#define CH341_BIT_DTR (1 << 5)

/******************************/
/* interrupt pipe definitions */
/******************************/
/* always 4 interrupt bytes */
/* first irq byte normally 0x08 */
/* second irq byte base 0x7d + below */
/* third irq byte base 0x94 + below */
/* fourth irq byte normally 0xee */

/* second interrupt byte */
#define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */

/* status returned in third interrupt answer byte, inverted in data
   from irq */
#define CH341_BIT_CTS 0x01
#define CH341_BIT_DSR 0x02
#define CH341_BIT_RI  0x04
#define CH341_BIT_DCD 0x08
#define CH341_BITS_MODEM_STAT 0x0f /* all bits */

/*******************************/
/* baudrate calculation factor */
/*******************************/
#define CH341_BAUDBASE_FACTOR 1532620800
#define CH341_BAUDBASE_DIVMAX 3

/* Break support - the information used to implement this was gleaned from
 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe.  Domo arigato.
 */

#define CH341_REQ_WRITE_REG    0x9A
#define CH341_REQ_READ_REG     0x95
#define CH341_REG_BREAK1       0x05
#define CH341_REG_BREAK2       0x18
#define CH341_NBREAK_BITS_REG1 0x01
#define CH341_NBREAK_BITS_REG2 0x40


static const struct usb_device_id id_table[] = {
	{ USB_DEVICE(0x4348, 0x5523) },
	{ USB_DEVICE(0x1a86, 0x7523) },
	{ USB_DEVICE(0x1a86, 0x5523) },
	{ },
};
MODULE_DEVICE_TABLE(usb, id_table);

struct ch341_private {
	spinlock_t lock; /* access lock */
	unsigned baud_rate; /* set baud rate */
	u8 line_control; /* set line control value RTS/DTR */
	u8 line_status; /* active status of modem control inputs */
	u8 multi_status_change; /* status changed multiple since last call */
};

static int ch341_control_out(struct usb_device *dev, u8 request,
			     u16 value, u16 index)
{
	int r;

	dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
		USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);

	r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
			    USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
			    value, index, NULL, 0, DEFAULT_TIMEOUT);

	return r;
}

static int ch341_control_in(struct usb_device *dev,
			    u8 request, u16 value, u16 index,
			    char *buf, unsigned bufsize)
{
	int r;

	dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
		USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
		(int)bufsize);

	r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
			    USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
			    value, index, buf, bufsize, DEFAULT_TIMEOUT);
	return r;
}

static int ch341_set_baudrate(struct usb_device *dev,
			      struct ch341_private *priv)
{
	short a, b;
	int r;
	unsigned long factor;
	short divisor;

	if (!priv->baud_rate)
		return -EINVAL;
	factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
	divisor = CH341_BAUDBASE_DIVMAX;

	while ((factor > 0xfff0) && divisor) {
		factor >>= 3;
		divisor--;
	}

	if (factor > 0xfff0)
		return -EINVAL;

	factor = 0x10000 - factor;
	a = (factor & 0xff00) | divisor;
	b = factor & 0xff;

	r = ch341_control_out(dev, 0x9a, 0x1312, a);
	if (!r)
		r = ch341_control_out(dev, 0x9a, 0x0f2c, b);

	return r;
}

static int ch341_set_handshake(struct usb_device *dev, u8 control)
{
	return ch341_control_out(dev, 0xa4, ~control, 0);
}

static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
{
	char *buffer;
	int r;
	const unsigned size = 8;
	unsigned long flags;

	buffer = kmalloc(size, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
	if (r < 0)
		goto out;

	/* setup the private status if available */
	if (r == 2) {
		r = 0;
		spin_lock_irqsave(&priv->lock, flags);
		priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
		priv->multi_status_change = 0;
		spin_unlock_irqrestore(&priv->lock, flags);
	} else
		r = -EPROTO;

out:	kfree(buffer);
	return r;
}

/* -------------------------------------------------------------------------- */

static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
{
	char *buffer;
	int r;
	const unsigned size = 8;

	buffer = kmalloc(size, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	/* expect two bytes 0x27 0x00 */
	r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
	if (r < 0)
		goto out;

	r = ch341_control_out(dev, 0xa1, 0, 0);
	if (r < 0)
		goto out;

	r = ch341_set_baudrate(dev, priv);
	if (r < 0)
		goto out;

	/* expect two bytes 0x56 0x00 */
	r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
	if (r < 0)
		goto out;

	r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
	if (r < 0)
		goto out;

	/* expect 0xff 0xee */
	r = ch341_get_status(dev, priv);
	if (r < 0)
		goto out;

	r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
	if (r < 0)
		goto out;

	r = ch341_set_baudrate(dev, priv);
	if (r < 0)
		goto out;

	r = ch341_set_handshake(dev, priv->line_control);
	if (r < 0)
		goto out;

	/* expect 0x9f 0xee */
	r = ch341_get_status(dev, priv);

out:	kfree(buffer);
	return r;
}

static int ch341_port_probe(struct usb_serial_port *port)
{
	struct ch341_private *priv;
	int r;

	priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	spin_lock_init(&priv->lock);
	priv->baud_rate = DEFAULT_BAUD_RATE;
	priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;

	r = ch341_configure(port->serial->dev, priv);
	if (r < 0)
		goto error;

	usb_set_serial_port_data(port, priv);
	return 0;

error:	kfree(priv);
	return r;
}

static int ch341_port_remove(struct usb_serial_port *port)
{
	struct ch341_private *priv;

	priv = usb_get_serial_port_data(port);
	kfree(priv);

	return 0;
}

static int ch341_carrier_raised(struct usb_serial_port *port)
{
	struct ch341_private *priv = usb_get_serial_port_data(port);
	if (priv->line_status & CH341_BIT_DCD)
		return 1;
	return 0;
}

static void ch341_dtr_rts(struct usb_serial_port *port, int on)
{
	struct ch341_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;

	/* drop DTR and RTS */
	spin_lock_irqsave(&priv->lock, flags);
	if (on)
		priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
	else
		priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
	spin_unlock_irqrestore(&priv->lock, flags);
	ch341_set_handshake(port->serial->dev, priv->line_control);
}

static void ch341_close(struct usb_serial_port *port)
{
	usb_serial_generic_close(port);
	usb_kill_urb(port->interrupt_in_urb);
}


/* open this device, set default parameters */
static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
{
	struct usb_serial *serial = port->serial;
	struct ch341_private *priv = usb_get_serial_port_data(port);
	int r;

	priv->baud_rate = DEFAULT_BAUD_RATE;

	r = ch341_configure(serial->dev, priv);
	if (r)
		goto out;

	r = ch341_set_handshake(serial->dev, priv->line_control);
	if (r)
		goto out;

	r = ch341_set_baudrate(serial->dev, priv);
	if (r)
		goto out;

	dev_dbg(&port->dev, "%s - submitting interrupt urb", __func__);
	r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
	if (r) {
		dev_err(&port->dev, "%s - failed submitting interrupt urb,"
			" error %d\n", __func__, r);
		ch341_close(port);
		goto out;
	}

	r = usb_serial_generic_open(tty, port);

out:	return r;
}

/* Old_termios contains the original termios settings and
 * tty->termios contains the new setting to be used.
 */
static void ch341_set_termios(struct tty_struct *tty,
		struct usb_serial_port *port, struct ktermios *old_termios)
{
	struct ch341_private *priv = usb_get_serial_port_data(port);
	unsigned baud_rate;
	unsigned long flags;

	baud_rate = tty_get_baud_rate(tty);

	priv->baud_rate = baud_rate;

	if (baud_rate) {
		spin_lock_irqsave(&priv->lock, flags);
		priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
		spin_unlock_irqrestore(&priv->lock, flags);
		ch341_set_baudrate(port->serial->dev, priv);
	} else {
		spin_lock_irqsave(&priv->lock, flags);
		priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
		spin_unlock_irqrestore(&priv->lock, flags);
	}

	ch341_set_handshake(port->serial->dev, priv->line_control);

	/* Unimplemented:
	 * (cflag & CSIZE) : data bits [5, 8]
	 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
	 * (cflag & CSTOPB) : stop bits [1, 2]
	 */
}

static void ch341_break_ctl(struct tty_struct *tty, int break_state)
{
	const uint16_t ch341_break_reg =
		CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
	struct usb_serial_port *port = tty->driver_data;
	int r;
	uint16_t reg_contents;
	uint8_t *break_reg;

	break_reg = kmalloc(2, GFP_KERNEL);
	if (!break_reg)
		return;

	r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
			ch341_break_reg, 0, break_reg, 2);
	if (r < 0) {
		dev_err(&port->dev, "%s - USB control read error (%d)\n",
				__func__, r);
		goto out;
	}
	dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
		__func__, break_reg[0], break_reg[1]);
	if (break_state != 0) {
		dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
		break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
		break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
	} else {
		dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
		break_reg[0] |= CH341_NBREAK_BITS_REG1;
		break_reg[1] |= CH341_NBREAK_BITS_REG2;
	}
	dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
		__func__, break_reg[0], break_reg[1]);
	reg_contents = get_unaligned_le16(break_reg);
	r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
			ch341_break_reg, reg_contents);
	if (r < 0)
		dev_err(&port->dev, "%s - USB control write error (%d)\n",
				__func__, r);
out:
	kfree(break_reg);
}

static int ch341_tiocmset(struct tty_struct *tty,
			  unsigned int set, unsigned int clear)
{
	struct usb_serial_port *port = tty->driver_data;
	struct ch341_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;
	u8 control;

	spin_lock_irqsave(&priv->lock, flags);
	if (set & TIOCM_RTS)
		priv->line_control |= CH341_BIT_RTS;
	if (set & TIOCM_DTR)
		priv->line_control |= CH341_BIT_DTR;
	if (clear & TIOCM_RTS)
		priv->line_control &= ~CH341_BIT_RTS;
	if (clear & TIOCM_DTR)
		priv->line_control &= ~CH341_BIT_DTR;
	control = priv->line_control;
	spin_unlock_irqrestore(&priv->lock, flags);

	return ch341_set_handshake(port->serial->dev, control);
}

static void ch341_read_int_callback(struct urb *urb)
{
	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
	unsigned char *data = urb->transfer_buffer;
	unsigned int actual_length = urb->actual_length;
	int status;

	switch (urb->status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
			__func__, urb->status);
		return;
	default:
		dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
			__func__, urb->status);
		goto exit;
	}

	usb_serial_debug_data(&port->dev, __func__,
			      urb->actual_length, urb->transfer_buffer);

	if (actual_length >= 4) {
		struct ch341_private *priv = usb_get_serial_port_data(port);
		unsigned long flags;
		u8 prev_line_status = priv->line_status;

		spin_lock_irqsave(&priv->lock, flags);
		priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
		if ((data[1] & CH341_MULT_STAT))
			priv->multi_status_change = 1;
		spin_unlock_irqrestore(&priv->lock, flags);

		if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
			struct tty_struct *tty = tty_port_tty_get(&port->port);
			if (tty)
				usb_serial_handle_dcd_change(port, tty,
					    priv->line_status & CH341_BIT_DCD);
			tty_kref_put(tty);
		}

		wake_up_interruptible(&port->port.delta_msr_wait);
	}

exit:
	status = usb_submit_urb(urb, GFP_ATOMIC);
	if (status)
		dev_err(&urb->dev->dev,
			"%s - usb_submit_urb failed with result %d\n",
			__func__, status);
}

static int ch341_tiocmiwait(struct tty_struct *tty, unsigned long arg)
{
	struct usb_serial_port *port = tty->driver_data;
	struct ch341_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;
	u8 prevstatus;
	u8 status;
	u8 changed;
	u8 multi_change = 0;

	spin_lock_irqsave(&priv->lock, flags);
	prevstatus = priv->line_status;
	priv->multi_status_change = 0;
	spin_unlock_irqrestore(&priv->lock, flags);

	while (!multi_change) {
		interruptible_sleep_on(&port->port.delta_msr_wait);
		/* see if a signal did it */
		if (signal_pending(current))
			return -ERESTARTSYS;

		if (port->serial->disconnected)
			return -EIO;

		spin_lock_irqsave(&priv->lock, flags);
		status = priv->line_status;
		multi_change = priv->multi_status_change;
		spin_unlock_irqrestore(&priv->lock, flags);

		changed = prevstatus ^ status;

		if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
		    ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
		    ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
		    ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
			return 0;
		}
		prevstatus = status;
	}

	return 0;
}

static int ch341_tiocmget(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct ch341_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;
	u8 mcr;
	u8 status;
	unsigned int result;

	spin_lock_irqsave(&priv->lock, flags);
	mcr = priv->line_control;
	status = priv->line_status;
	spin_unlock_irqrestore(&priv->lock, flags);

	result = ((mcr & CH341_BIT_DTR)		? TIOCM_DTR : 0)
		  | ((mcr & CH341_BIT_RTS)	? TIOCM_RTS : 0)
		  | ((status & CH341_BIT_CTS)	? TIOCM_CTS : 0)
		  | ((status & CH341_BIT_DSR)	? TIOCM_DSR : 0)
		  | ((status & CH341_BIT_RI)	? TIOCM_RI  : 0)
		  | ((status & CH341_BIT_DCD)	? TIOCM_CD  : 0);

	dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);

	return result;
}

static int ch341_reset_resume(struct usb_serial *serial)
{
	struct ch341_private *priv;

	priv = usb_get_serial_port_data(serial->port[0]);

	/* reconfigure ch341 serial port after bus-reset */
	ch341_configure(serial->dev, priv);

	return 0;
}

static struct usb_serial_driver ch341_device = {
	.driver = {
		.owner	= THIS_MODULE,
		.name	= "ch341-uart",
	},
	.id_table          = id_table,
	.num_ports         = 1,
	.open              = ch341_open,
	.dtr_rts	   = ch341_dtr_rts,
	.carrier_raised	   = ch341_carrier_raised,
	.close             = ch341_close,
	.set_termios       = ch341_set_termios,
	.break_ctl         = ch341_break_ctl,
	.tiocmget          = ch341_tiocmget,
	.tiocmset          = ch341_tiocmset,
	.tiocmiwait        = ch341_tiocmiwait,
	.read_int_callback = ch341_read_int_callback,
	.port_probe        = ch341_port_probe,
	.port_remove       = ch341_port_remove,
	.reset_resume      = ch341_reset_resume,
};

static struct usb_serial_driver * const serial_drivers[] = {
	&ch341_device, NULL
};

module_usb_serial_driver(serial_drivers, id_table);

MODULE_LICENSE("GPL");
Commit	Line	Data
6ce76104 FK	1	/*
6ce76104 FK	2	* Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
664d5df9 WC	3	* Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
664d5df9 WC	4	* Copyright 2009, Boris Hajduk <boris@hajduk.org>
6ce76104 FK	5	*
	6	* ch341.c implements a serial port driver for the Winchiphead CH341.
	7	*
	8	* The CH341 device can be used to implement an RS232 asynchronous
	9	* serial port, an IEEE-1284 parallel printer port or a memory-like
	10	* interface. In all cases the CH341 supports an I2C interface as well.
	11	* This driver only supports the asynchronous serial interface.
	12	*
	13	* This program is free software; you can redistribute it and/or
	14	* modify it under the terms of the GNU General Public License version
	15	* 2 as published by the Free Software Foundation.
	16	*/
	17
	18	#include <linux/kernel.h>
	19	#include <linux/init.h>
	20	#include <linux/tty.h>
	21	#include <linux/module.h>
5a0e3ad6	22	#include <linux/slab.h>
6ce76104 FK	23	#include <linux/usb.h>
	24	#include <linux/usb/serial.h>
	25	#include <linux/serial.h>
5be796f0	26	#include <asm/unaligned.h>
6ce76104	27
664d5df9	28	#define DEFAULT_BAUD_RATE 9600
6ce76104 FK	29	#define DEFAULT_TIMEOUT 1000
6ce76104 FK	30
664d5df9 WC	31	/* flags for IO-Bits */
	32	#define CH341_BIT_RTS (1 << 6)
	33	#define CH341_BIT_DTR (1 << 5)
	34
	35	/******************************/
	36	/* interrupt pipe definitions */
	37	/******************************/
	38	/* always 4 interrupt bytes */
	39	/* first irq byte normally 0x08 */
	40	/* second irq byte base 0x7d + below */
	41	/* third irq byte base 0x94 + below */
	42	/* fourth irq byte normally 0xee */
	43
	44	/* second interrupt byte */
	45	#define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
	46
	47	/* status returned in third interrupt answer byte, inverted in data
	48	from irq */
	49	#define CH341_BIT_CTS 0x01
	50	#define CH341_BIT_DSR 0x02
	51	#define CH341_BIT_RI 0x04
	52	#define CH341_BIT_DCD 0x08
	53	#define CH341_BITS_MODEM_STAT 0x0f /* all bits */
	54
	55	/*******************************/
	56	/* baudrate calculation factor */
	57	/*******************************/
	58	#define CH341_BAUDBASE_FACTOR 1532620800
	59	#define CH341_BAUDBASE_DIVMAX 3
	60
492896f0 TS	61	/* Break support - the information used to implement this was gleaned from
	62	* the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
	63	*/
	64
	65	#define CH341_REQ_WRITE_REG 0x9A
	66	#define CH341_REQ_READ_REG 0x95
	67	#define CH341_REG_BREAK1 0x05
	68	#define CH341_REG_BREAK2 0x18
	69	#define CH341_NBREAK_BITS_REG1 0x01
	70	#define CH341_NBREAK_BITS_REG2 0x40
	71
	72
7d40d7e8	73	static const struct usb_device_id id_table[] = {
6ce76104	74	{ USB_DEVICE(0x4348, 0x5523) },
82078234	75	{ USB_DEVICE(0x1a86, 0x7523) },
d0781383	76	{ USB_DEVICE(0x1a86, 0x5523) },
6ce76104 FK	77	{ },
	78	};
	79	MODULE_DEVICE_TABLE(usb, id_table);
	80
	81	struct ch341_private {
664d5df9	82	spinlock_t lock; /* access lock */
664d5df9 WC	83	unsigned baud_rate; /* set baud rate */
	84	u8 line_control; /* set line control value RTS/DTR */
	85	u8 line_status; /* active status of modem control inputs */
	86	u8 multi_status_change; /* status changed multiple since last call */
6ce76104 FK	87	};
	88
	89	static int ch341_control_out(struct usb_device *dev, u8 request,
	90	u16 value, u16 index)
	91	{
	92	int r;
79cbeeaf GKH	93
	94	dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
	95	USB_DIR_OUT\|0x40, (int)request, (int)value, (int)index);
6ce76104 FK	96
	97	r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
	98	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_OUT,
	99	value, index, NULL, 0, DEFAULT_TIMEOUT);
	100
	101	return r;
	102	}
	103
	104	static int ch341_control_in(struct usb_device *dev,
	105	u8 request, u16 value, u16 index,
	106	char *buf, unsigned bufsize)
	107	{
	108	int r;
79cbeeaf GKH	109
	110	dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
	111	USB_DIR_IN\|0x40, (int)request, (int)value, (int)index, buf,
	112	(int)bufsize);
6ce76104 FK	113
	114	r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
	115	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,
	116	value, index, buf, bufsize, DEFAULT_TIMEOUT);
	117	return r;
	118	}
	119
93b6497d AB	120	static int ch341_set_baudrate(struct usb_device *dev,
93b6497d AB	121	struct ch341_private *priv)
6ce76104 FK	122	{
	123	short a, b;
	124	int r;
664d5df9 WC	125	unsigned long factor;
664d5df9 WC	126	short divisor;
6ce76104	127
664d5df9	128	if (!priv->baud_rate)
6ce76104	129	return -EINVAL;
664d5df9 WC	130	factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
	131	divisor = CH341_BAUDBASE_DIVMAX;
	132
	133	while ((factor > 0xfff0) && divisor) {
	134	factor >>= 3;
	135	divisor--;
6ce76104 FK	136	}
6ce76104 FK	137
664d5df9 WC	138	if (factor > 0xfff0)
	139	return -EINVAL;
	140
	141	factor = 0x10000 - factor;
	142	a = (factor & 0xff00) \| divisor;
	143	b = factor & 0xff;
	144
6ce76104 FK	145	r = ch341_control_out(dev, 0x9a, 0x1312, a);
	146	if (!r)
	147	r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
	148
	149	return r;
	150	}
	151
664d5df9	152	static int ch341_set_handshake(struct usb_device *dev, u8 control)
6ce76104	153	{
664d5df9	154	return ch341_control_out(dev, 0xa4, ~control, 0);
6ce76104 FK	155	}
6ce76104 FK	156
664d5df9	157	static int ch341_get_status(struct usb_device dev, struct ch341_private priv)
6ce76104 FK	158	{
	159	char *buffer;
	160	int r;
	161	const unsigned size = 8;
664d5df9	162	unsigned long flags;
6ce76104	163
6ce76104 FK	164	buffer = kmalloc(size, GFP_KERNEL);
	165	if (!buffer)
	166	return -ENOMEM;
	167
	168	r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
c4d0f8cb	169	if (r < 0)
6ce76104 FK	170	goto out;
6ce76104 FK	171
664d5df9 WC	172	/* setup the private status if available */
	173	if (r == 2) {
	174	r = 0;
	175	spin_lock_irqsave(&priv->lock, flags);
	176	priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
	177	priv->multi_status_change = 0;
	178	spin_unlock_irqrestore(&priv->lock, flags);
	179	} else
	180	r = -EPROTO;
6ce76104 FK	181
	182	out: kfree(buffer);
	183	return r;
	184	}
	185
	186	/* -------------------------------------------------------------------------- */
	187
93b6497d	188	static int ch341_configure(struct usb_device dev, struct ch341_private priv)
6ce76104 FK	189	{
	190	char *buffer;
	191	int r;
	192	const unsigned size = 8;
	193
6ce76104 FK	194	buffer = kmalloc(size, GFP_KERNEL);
	195	if (!buffer)
	196	return -ENOMEM;
	197
	198	/* expect two bytes 0x27 0x00 */
	199	r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
	200	if (r < 0)
	201	goto out;
	202
	203	r = ch341_control_out(dev, 0xa1, 0, 0);
	204	if (r < 0)
	205	goto out;
	206
	207	r = ch341_set_baudrate(dev, priv);
	208	if (r < 0)
	209	goto out;
	210
	211	/* expect two bytes 0x56 0x00 */
	212	r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
	213	if (r < 0)
	214	goto out;
	215
	216	r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
	217	if (r < 0)
	218	goto out;
	219
	220	/* expect 0xff 0xee */
664d5df9	221	r = ch341_get_status(dev, priv);
6ce76104 FK	222	if (r < 0)
	223	goto out;
	224
	225	r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
	226	if (r < 0)
	227	goto out;
	228
	229	r = ch341_set_baudrate(dev, priv);
	230	if (r < 0)
	231	goto out;
	232
664d5df9	233	r = ch341_set_handshake(dev, priv->line_control);
6ce76104 FK	234	if (r < 0)
	235	goto out;
	236
	237	/* expect 0x9f 0xee */
664d5df9	238	r = ch341_get_status(dev, priv);
6ce76104 FK	239
	240	out: kfree(buffer);
	241	return r;
	242	}
	243
456c5be5	244	static int ch341_port_probe(struct usb_serial_port *port)
6ce76104 FK	245	{
	246	struct ch341_private *priv;
	247	int r;
	248
6ce76104 FK	249	priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
	250	if (!priv)
	251	return -ENOMEM;
	252
664d5df9	253	spin_lock_init(&priv->lock);
6ce76104	254	priv->baud_rate = DEFAULT_BAUD_RATE;
664d5df9	255	priv->line_control = CH341_BIT_RTS \| CH341_BIT_DTR;
6ce76104	256
456c5be5	257	r = ch341_configure(port->serial->dev, priv);
6ce76104 FK	258	if (r < 0)
	259	goto error;
	260
456c5be5	261	usb_set_serial_port_data(port, priv);
6ce76104 FK	262	return 0;
	263
	264	error: kfree(priv);
	265	return r;
	266	}
	267
456c5be5 JH	268	static int ch341_port_remove(struct usb_serial_port *port)
	269	{
	270	struct ch341_private *priv;
	271
	272	priv = usb_get_serial_port_data(port);
	273	kfree(priv);
	274
	275	return 0;
	276	}
	277
335f8514 AC	278	static int ch341_carrier_raised(struct usb_serial_port *port)
	279	{
	280	struct ch341_private *priv = usb_get_serial_port_data(port);
	281	if (priv->line_status & CH341_BIT_DCD)
	282	return 1;
	283	return 0;
	284	}
	285
	286	static void ch341_dtr_rts(struct usb_serial_port *port, int on)
664d5df9 WC	287	{
	288	struct ch341_private *priv = usb_get_serial_port_data(port);
	289	unsigned long flags;
664d5df9	290
335f8514 AC	291	/* drop DTR and RTS */
	292	spin_lock_irqsave(&priv->lock, flags);
	293	if (on)
	294	priv->line_control \|= CH341_BIT_RTS \| CH341_BIT_DTR;
	295	else
	296	priv->line_control &= ~(CH341_BIT_RTS \| CH341_BIT_DTR);
	297	spin_unlock_irqrestore(&priv->lock, flags);
	298	ch341_set_handshake(port->serial->dev, priv->line_control);
335f8514 AC	299	}
	300
	301	static void ch341_close(struct usb_serial_port *port)
	302	{
f26788da	303	usb_serial_generic_close(port);
664d5df9	304	usb_kill_urb(port->interrupt_in_urb);
664d5df9 WC	305	}
	306
	307
6ce76104	308	/* open this device, set default parameters */
a509a7e4	309	static int ch341_open(struct tty_struct tty, struct usb_serial_port port)
6ce76104 FK	310	{
6ce76104 FK	311	struct usb_serial *serial = port->serial;
456c5be5	312	struct ch341_private *priv = usb_get_serial_port_data(port);
6ce76104 FK	313	int r;
6ce76104 FK	314
6ce76104	315	priv->baud_rate = DEFAULT_BAUD_RATE;
6ce76104 FK	316
	317	r = ch341_configure(serial->dev, priv);
	318	if (r)
	319	goto out;
	320
664d5df9	321	r = ch341_set_handshake(serial->dev, priv->line_control);
6ce76104 FK	322	if (r)
	323	goto out;
	324
	325	r = ch341_set_baudrate(serial->dev, priv);
	326	if (r)
	327	goto out;
	328
79cbeeaf	329	dev_dbg(&port->dev, "%s - submitting interrupt urb", __func__);
664d5df9 WC	330	r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
	331	if (r) {
	332	dev_err(&port->dev, "%s - failed submitting interrupt urb,"
	333	" error %d\n", __func__, r);
335f8514	334	ch341_close(port);
06946a66	335	goto out;
664d5df9 WC	336	}
664d5df9 WC	337
a509a7e4	338	r = usb_serial_generic_open(tty, port);
6ce76104 FK	339
	340	out: return r;
	341	}
	342
	343	/* Old_termios contains the original termios settings and
	344	* tty->termios contains the new setting to be used.
	345	*/
95da310e AC	346	static void ch341_set_termios(struct tty_struct *tty,
95da310e AC	347	struct usb_serial_port port, struct ktermios old_termios)
6ce76104 FK	348	{
6ce76104 FK	349	struct ch341_private *priv = usb_get_serial_port_data(port);
6ce76104	350	unsigned baud_rate;
664d5df9	351	unsigned long flags;
6ce76104	352
6ce76104 FK	353	baud_rate = tty_get_baud_rate(tty);
6ce76104 FK	354
664d5df9 WC	355	priv->baud_rate = baud_rate;
	356
	357	if (baud_rate) {
	358	spin_lock_irqsave(&priv->lock, flags);
	359	priv->line_control \|= (CH341_BIT_DTR \| CH341_BIT_RTS);
	360	spin_unlock_irqrestore(&priv->lock, flags);
	361	ch341_set_baudrate(port->serial->dev, priv);
	362	} else {
	363	spin_lock_irqsave(&priv->lock, flags);
	364	priv->line_control &= ~(CH341_BIT_DTR \| CH341_BIT_RTS);
	365	spin_unlock_irqrestore(&priv->lock, flags);
6ce76104 FK	366	}
6ce76104 FK	367
664d5df9	368	ch341_set_handshake(port->serial->dev, priv->line_control);
6ce76104 FK	369
	370	/* Unimplemented:
	371	* (cflag & CSIZE) : data bits [5, 8]
	372	* (cflag & PARENB) : parity {NONE, EVEN, ODD}
	373	* (cflag & CSTOPB) : stop bits [1, 2]
	374	*/
664d5df9 WC	375	}
664d5df9 WC	376
492896f0 TS	377	static void ch341_break_ctl(struct tty_struct *tty, int break_state)
	378	{
	379	const uint16_t ch341_break_reg =
	380	CH341_REG_BREAK1 \| ((uint16_t) CH341_REG_BREAK2 << 8);
	381	struct usb_serial_port *port = tty->driver_data;
	382	int r;
	383	uint16_t reg_contents;
f2b5cc83	384	uint8_t *break_reg;
492896f0	385
f2b5cc83	386	break_reg = kmalloc(2, GFP_KERNEL);
10c642d0	387	if (!break_reg)
f2b5cc83	388	return;
f2b5cc83	389
492896f0	390	r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
f2b5cc83	391	ch341_break_reg, 0, break_reg, 2);
492896f0	392	if (r < 0) {
6a9b15fe JH	393	dev_err(&port->dev, "%s - USB control read error (%d)\n",
6a9b15fe JH	394	__func__, r);
f2b5cc83	395	goto out;
492896f0	396	}
79cbeeaf GKH	397	dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
79cbeeaf GKH	398	__func__, break_reg[0], break_reg[1]);
492896f0	399	if (break_state != 0) {
79cbeeaf	400	dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
492896f0 TS	401	break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
	402	break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
	403	} else {
79cbeeaf	404	dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
492896f0 TS	405	break_reg[0] \|= CH341_NBREAK_BITS_REG1;
	406	break_reg[1] \|= CH341_NBREAK_BITS_REG2;
	407	}
79cbeeaf GKH	408	dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
79cbeeaf GKH	409	__func__, break_reg[0], break_reg[1]);
5be796f0	410	reg_contents = get_unaligned_le16(break_reg);
492896f0 TS	411	r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
	412	ch341_break_reg, reg_contents);
	413	if (r < 0)
6a9b15fe JH	414	dev_err(&port->dev, "%s - USB control write error (%d)\n",
6a9b15fe JH	415	__func__, r);
f2b5cc83 JH	416	out:
f2b5cc83 JH	417	kfree(break_reg);
492896f0 TS	418	}
492896f0 TS	419
20b9d177	420	static int ch341_tiocmset(struct tty_struct *tty,
664d5df9 WC	421	unsigned int set, unsigned int clear)
	422	{
	423	struct usb_serial_port *port = tty->driver_data;
	424	struct ch341_private *priv = usb_get_serial_port_data(port);
	425	unsigned long flags;
	426	u8 control;
	427
	428	spin_lock_irqsave(&priv->lock, flags);
	429	if (set & TIOCM_RTS)
	430	priv->line_control \|= CH341_BIT_RTS;
	431	if (set & TIOCM_DTR)
	432	priv->line_control \|= CH341_BIT_DTR;
	433	if (clear & TIOCM_RTS)
	434	priv->line_control &= ~CH341_BIT_RTS;
	435	if (clear & TIOCM_DTR)
	436	priv->line_control &= ~CH341_BIT_DTR;
	437	control = priv->line_control;
	438	spin_unlock_irqrestore(&priv->lock, flags);
	439
	440	return ch341_set_handshake(port->serial->dev, control);
	441	}
	442
	443	static void ch341_read_int_callback(struct urb *urb)
	444	{
	445	struct usb_serial_port port = (struct usb_serial_port ) urb->context;
	446	unsigned char *data = urb->transfer_buffer;
	447	unsigned int actual_length = urb->actual_length;
	448	int status;
	449
664d5df9 WC	450	switch (urb->status) {
	451	case 0:
	452	/* success */
	453	break;
	454	case -ECONNRESET:
	455	case -ENOENT:
	456	case -ESHUTDOWN:
	457	/* this urb is terminated, clean up */
79cbeeaf GKH	458	dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
79cbeeaf GKH	459	__func__, urb->status);
664d5df9 WC	460	return;
664d5df9 WC	461	default:
79cbeeaf GKH	462	dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
79cbeeaf GKH	463	__func__, urb->status);
664d5df9 WC	464	goto exit;
	465	}
	466
59d33f2f	467	usb_serial_debug_data(&port->dev, __func__,
664d5df9 WC	468	urb->actual_length, urb->transfer_buffer);
	469
	470	if (actual_length >= 4) {
	471	struct ch341_private *priv = usb_get_serial_port_data(port);
	472	unsigned long flags;
d14fc1a7	473	u8 prev_line_status = priv->line_status;
664d5df9 WC	474
	475	spin_lock_irqsave(&priv->lock, flags);
	476	priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
	477	if ((data[1] & CH341_MULT_STAT))
	478	priv->multi_status_change = 1;
	479	spin_unlock_irqrestore(&priv->lock, flags);
d14fc1a7 LP	480
	481	if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
	482	struct tty_struct *tty = tty_port_tty_get(&port->port);
	483	if (tty)
	484	usb_serial_handle_dcd_change(port, tty,
	485	priv->line_status & CH341_BIT_DCD);
	486	tty_kref_put(tty);
	487	}
	488
3f550431	489	wake_up_interruptible(&port->port.delta_msr_wait);
664d5df9 WC	490	}
	491
	492	exit:
	493	status = usb_submit_urb(urb, GFP_ATOMIC);
	494	if (status)
	495	dev_err(&urb->dev->dev,
	496	"%s - usb_submit_urb failed with result %d\n",
	497	__func__, status);
	498	}
	499
7bb98f0e	500	static int ch341_tiocmiwait(struct tty_struct *tty, unsigned long arg)
664d5df9	501	{
7bb98f0e	502	struct usb_serial_port *port = tty->driver_data;
664d5df9 WC	503	struct ch341_private *priv = usb_get_serial_port_data(port);
	504	unsigned long flags;
	505	u8 prevstatus;
	506	u8 status;
	507	u8 changed;
	508	u8 multi_change = 0;
	509
	510	spin_lock_irqsave(&priv->lock, flags);
	511	prevstatus = priv->line_status;
	512	priv->multi_status_change = 0;
	513	spin_unlock_irqrestore(&priv->lock, flags);
	514
	515	while (!multi_change) {
3f550431	516	interruptible_sleep_on(&port->port.delta_msr_wait);
664d5df9 WC	517	/* see if a signal did it */
	518	if (signal_pending(current))
	519	return -ERESTARTSYS;
	520
fa1e11d5 JH	521	if (port->serial->disconnected)
	522	return -EIO;
	523
664d5df9 WC	524	spin_lock_irqsave(&priv->lock, flags);
	525	status = priv->line_status;
	526	multi_change = priv->multi_status_change;
	527	spin_unlock_irqrestore(&priv->lock, flags);
	528
	529	changed = prevstatus ^ status;
	530
	531	if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) \|\|
	532	((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) \|\|
	533	((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) \|\|
	534	((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
	535	return 0;
	536	}
	537	prevstatus = status;
	538	}
	539
	540	return 0;
	541	}
	542
60b33c13	543	static int ch341_tiocmget(struct tty_struct *tty)
664d5df9 WC	544	{
	545	struct usb_serial_port *port = tty->driver_data;
	546	struct ch341_private *priv = usb_get_serial_port_data(port);
	547	unsigned long flags;
	548	u8 mcr;
	549	u8 status;
	550	unsigned int result;
	551
664d5df9 WC	552	spin_lock_irqsave(&priv->lock, flags);
	553	mcr = priv->line_control;
	554	status = priv->line_status;
	555	spin_unlock_irqrestore(&priv->lock, flags);
	556
	557	result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
	558	\| ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
	559	\| ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
	560	\| ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
	561	\| ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
	562	\| ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
	563
79cbeeaf	564	dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
73f59308	565
664d5df9	566	return result;
6ce76104 FK	567	}
6ce76104 FK	568
622b80cf	569	static int ch341_reset_resume(struct usb_serial *serial)
1ded7ea4	570	{
1ded7ea4 ML	571	struct ch341_private *priv;
1ded7ea4 ML	572
1ded7ea4 ML	573	priv = usb_get_serial_port_data(serial->port[0]);
1ded7ea4 ML	574
2bfd1c96 GKH	575	/* reconfigure ch341 serial port after bus-reset */
2bfd1c96 GKH	576	ch341_configure(serial->dev, priv);
1ded7ea4 ML	577
	578	return 0;
	579	}
	580
6ce76104 FK	581	static struct usb_serial_driver ch341_device = {
	582	.driver = {
	583	.owner = THIS_MODULE,
	584	.name = "ch341-uart",
	585	},
664d5df9	586	.id_table = id_table,
664d5df9 WC	587	.num_ports = 1,
664d5df9 WC	588	.open = ch341_open,
335f8514 AC	589	.dtr_rts = ch341_dtr_rts,
335f8514 AC	590	.carrier_raised = ch341_carrier_raised,
664d5df9	591	.close = ch341_close,
664d5df9	592	.set_termios = ch341_set_termios,
492896f0	593	.break_ctl = ch341_break_ctl,
664d5df9 WC	594	.tiocmget = ch341_tiocmget,
664d5df9 WC	595	.tiocmset = ch341_tiocmset,
7bb98f0e	596	.tiocmiwait = ch341_tiocmiwait,
664d5df9	597	.read_int_callback = ch341_read_int_callback,
456c5be5 JH	598	.port_probe = ch341_port_probe,
456c5be5 JH	599	.port_remove = ch341_port_remove,
1c1eaba8	600	.reset_resume = ch341_reset_resume,
6ce76104 FK	601	};
6ce76104 FK	602
08a4f6bc AS	603	static struct usb_serial_driver * const serial_drivers[] = {
	604	&ch341_device, NULL
	605	};
	606
68e24113	607	module_usb_serial_driver(serial_drivers, id_table);
6ce76104	608
6ce76104	609	MODULE_LICENSE("GPL");