diff options
Diffstat (limited to 'drivers/usb/serial/ch341.c')
| -rw-r--r-- | drivers/usb/serial/ch341.c | 580 |
1 files changed, 580 insertions, 0 deletions
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c new file mode 100644 index 000000000..c73808f09 --- /dev/null +++ b/drivers/usb/serial/ch341.c @@ -0,0 +1,580 @@ +/* + * 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/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 */ +}; + +static void ch341_set_termios(struct tty_struct *tty, + struct usb_serial_port *port, + struct ktermios *old_termios); + +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; + 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; + + r = ch341_configure(serial->dev, priv); + if (r) + goto out; + + if (tty) + ch341_set_termios(tty, port, NULL); + + dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__); + r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); + if (r) { + dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n", + __func__, r); + 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_update_line_status(struct usb_serial_port *port, + unsigned char *data, size_t len) +{ + struct ch341_private *priv = usb_get_serial_port_data(port); + struct tty_struct *tty; + unsigned long flags; + u8 status; + u8 delta; + + if (len < 4) + return; + + status = ~data[2] & CH341_BITS_MODEM_STAT; + + spin_lock_irqsave(&priv->lock, flags); + delta = status ^ priv->line_status; + priv->line_status = status; + spin_unlock_irqrestore(&priv->lock, flags); + + if (data[1] & CH341_MULT_STAT) + dev_dbg(&port->dev, "%s - multiple status change\n", __func__); + + if (!delta) + return; + + if (delta & CH341_BIT_CTS) + port->icount.cts++; + if (delta & CH341_BIT_DSR) + port->icount.dsr++; + if (delta & CH341_BIT_RI) + port->icount.rng++; + if (delta & CH341_BIT_DCD) { + port->icount.dcd++; + tty = tty_port_tty_get(&port->port); + if (tty) { + usb_serial_handle_dcd_change(port, tty, + status & CH341_BIT_DCD); + tty_kref_put(tty); + } + } + + wake_up_interruptible(&port->port.delta_msr_wait); +} + +static void ch341_read_int_callback(struct urb *urb) +{ + struct usb_serial_port *port = urb->context; + unsigned char *data = urb->transfer_buffer; + unsigned int len = 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: %d\n", + __func__, urb->status); + return; + default: + dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n", + __func__, urb->status); + goto exit; + } + + usb_serial_debug_data(&port->dev, __func__, len, data); + ch341_update_line_status(port, data, len); +exit: + status = usb_submit_urb(urb, GFP_ATOMIC); + if (status) { + dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n", + __func__, status); + } +} + +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 = usb_serial_generic_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"); |