diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/usb/serial/ch341.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/usb/serial/ch341.c')
-rw-r--r-- | drivers/usb/serial/ch341.c | 857 |
1 files changed, 857 insertions, 0 deletions
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c new file mode 100644 index 000000000..6e1b87e67 --- /dev/null +++ b/drivers/usb/serial/ch341.c @@ -0,0 +1,857 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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. + */ + +#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 */ + +/* 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_READ_VERSION 0x5F +#define CH341_REQ_WRITE_REG 0x9A +#define CH341_REQ_READ_REG 0x95 +#define CH341_REQ_SERIAL_INIT 0xA1 +#define CH341_REQ_MODEM_CTRL 0xA4 + +#define CH341_REG_BREAK 0x05 +#define CH341_REG_PRESCALER 0x12 +#define CH341_REG_DIVISOR 0x13 +#define CH341_REG_LCR 0x18 +#define CH341_REG_LCR2 0x25 + +#define CH341_NBREAK_BITS 0x01 + +#define CH341_LCR_ENABLE_RX 0x80 +#define CH341_LCR_ENABLE_TX 0x40 +#define CH341_LCR_MARK_SPACE 0x20 +#define CH341_LCR_PAR_EVEN 0x10 +#define CH341_LCR_ENABLE_PAR 0x08 +#define CH341_LCR_STOP_BITS_2 0x04 +#define CH341_LCR_CS8 0x03 +#define CH341_LCR_CS7 0x02 +#define CH341_LCR_CS6 0x01 +#define CH341_LCR_CS5 0x00 + +#define CH341_QUIRK_LIMITED_PRESCALER BIT(0) +#define CH341_QUIRK_SIMULATE_BREAK BIT(1) + +static const struct usb_device_id id_table[] = { + { USB_DEVICE(0x1a86, 0x5523) }, + { USB_DEVICE(0x1a86, 0x7522) }, + { USB_DEVICE(0x1a86, 0x7523) }, + { USB_DEVICE(0x2184, 0x0057) }, + { USB_DEVICE(0x4348, 0x5523) }, + { USB_DEVICE(0x9986, 0x7523) }, + { }, +}; +MODULE_DEVICE_TABLE(usb, id_table); + +struct ch341_private { + spinlock_t lock; /* access lock */ + unsigned baud_rate; /* set baud rate */ + u8 mcr; + u8 msr; + u8 lcr; + + unsigned long quirks; + u8 version; + + unsigned long break_end; +}; + +static void ch341_set_termios(struct tty_struct *tty, + struct usb_serial_port *port, + const 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, "%s - (%02x,%04x,%04x)\n", __func__, + request, value, 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); + if (r < 0) + dev_err(&dev->dev, "failed to send control message: %d\n", r); + + 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, "%s - (%02x,%04x,%04x,%u)\n", __func__, + request, value, index, bufsize); + + r = usb_control_msg_recv(dev, 0, request, + USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, + value, index, buf, bufsize, DEFAULT_TIMEOUT, + GFP_KERNEL); + if (r) { + dev_err(&dev->dev, "failed to receive control message: %d\n", + r); + return r; + } + + return 0; +} + +#define CH341_CLKRATE 48000000 +#define CH341_CLK_DIV(ps, fact) (1 << (12 - 3 * (ps) - (fact))) +#define CH341_MIN_RATE(ps) (CH341_CLKRATE / (CH341_CLK_DIV((ps), 1) * 512)) + +static const speed_t ch341_min_rates[] = { + CH341_MIN_RATE(0), + CH341_MIN_RATE(1), + CH341_MIN_RATE(2), + CH341_MIN_RATE(3), +}; + +/* Supported range is 46 to 3000000 bps. */ +#define CH341_MIN_BPS DIV_ROUND_UP(CH341_CLKRATE, CH341_CLK_DIV(0, 0) * 256) +#define CH341_MAX_BPS (CH341_CLKRATE / (CH341_CLK_DIV(3, 0) * 2)) + +/* + * The device line speed is given by the following equation: + * + * baudrate = 48000000 / (2^(12 - 3 * ps - fact) * div), where + * + * 0 <= ps <= 3, + * 0 <= fact <= 1, + * 2 <= div <= 256 if fact = 0, or + * 9 <= div <= 256 if fact = 1 + */ +static int ch341_get_divisor(struct ch341_private *priv, speed_t speed) +{ + unsigned int fact, div, clk_div; + bool force_fact0 = false; + int ps; + + /* + * Clamp to supported range, this makes the (ps < 0) and (div < 2) + * sanity checks below redundant. + */ + speed = clamp_val(speed, CH341_MIN_BPS, CH341_MAX_BPS); + + /* + * Start with highest possible base clock (fact = 1) that will give a + * divisor strictly less than 512. + */ + fact = 1; + for (ps = 3; ps >= 0; ps--) { + if (speed > ch341_min_rates[ps]) + break; + } + + if (ps < 0) + return -EINVAL; + + /* Determine corresponding divisor, rounding down. */ + clk_div = CH341_CLK_DIV(ps, fact); + div = CH341_CLKRATE / (clk_div * speed); + + /* Some devices require a lower base clock if ps < 3. */ + if (ps < 3 && (priv->quirks & CH341_QUIRK_LIMITED_PRESCALER)) + force_fact0 = true; + + /* Halve base clock (fact = 0) if required. */ + if (div < 9 || div > 255 || force_fact0) { + div /= 2; + clk_div *= 2; + fact = 0; + } + + if (div < 2) + return -EINVAL; + + /* + * Pick next divisor if resulting rate is closer to the requested one, + * scale up to avoid rounding errors on low rates. + */ + if (16 * CH341_CLKRATE / (clk_div * div) - 16 * speed >= + 16 * speed - 16 * CH341_CLKRATE / (clk_div * (div + 1))) + div++; + + /* + * Prefer lower base clock (fact = 0) if even divisor. + * + * Note that this makes the receiver more tolerant to errors. + */ + if (fact == 1 && div % 2 == 0) { + div /= 2; + fact = 0; + } + + return (0x100 - div) << 8 | fact << 2 | ps; +} + +static int ch341_set_baudrate_lcr(struct usb_device *dev, + struct ch341_private *priv, + speed_t baud_rate, u8 lcr) +{ + int val; + int r; + + if (!baud_rate) + return -EINVAL; + + val = ch341_get_divisor(priv, baud_rate); + if (val < 0) + return -EINVAL; + + /* + * CH341A buffers data until a full endpoint-size packet (32 bytes) + * has been received unless bit 7 is set. + * + * At least one device with version 0x27 appears to have this bit + * inverted. + */ + if (priv->version > 0x27) + val |= BIT(7); + + r = ch341_control_out(dev, CH341_REQ_WRITE_REG, + CH341_REG_DIVISOR << 8 | CH341_REG_PRESCALER, + val); + if (r) + return r; + + /* + * Chip versions before version 0x30 as read using + * CH341_REQ_READ_VERSION used separate registers for line control + * (stop bits, parity and word length). Version 0x30 and above use + * CH341_REG_LCR only and CH341_REG_LCR2 is always set to zero. + */ + if (priv->version < 0x30) + return 0; + + r = ch341_control_out(dev, CH341_REQ_WRITE_REG, + CH341_REG_LCR2 << 8 | CH341_REG_LCR, lcr); + if (r) + return r; + + return r; +} + +static int ch341_set_handshake(struct usb_device *dev, u8 control) +{ + return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0); +} + +static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) +{ + const unsigned int size = 2; + u8 buffer[2]; + int r; + unsigned long flags; + + r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size); + if (r) + return r; + + spin_lock_irqsave(&priv->lock, flags); + priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT; + spin_unlock_irqrestore(&priv->lock, flags); + + return 0; +} + +/* -------------------------------------------------------------------------- */ + +static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) +{ + const unsigned int size = 2; + u8 buffer[2]; + int r; + + /* expect two bytes 0x27 0x00 */ + r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size); + if (r) + return r; + + priv->version = buffer[0]; + dev_dbg(&dev->dev, "Chip version: 0x%02x\n", priv->version); + + r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0); + if (r < 0) + return r; + + r = ch341_set_baudrate_lcr(dev, priv, priv->baud_rate, priv->lcr); + if (r < 0) + return r; + + r = ch341_set_handshake(dev, priv->mcr); + if (r < 0) + return r; + + return 0; +} + +static int ch341_detect_quirks(struct usb_serial_port *port) +{ + struct ch341_private *priv = usb_get_serial_port_data(port); + struct usb_device *udev = port->serial->dev; + const unsigned int size = 2; + unsigned long quirks = 0; + u8 buffer[2]; + int r; + + /* + * A subset of CH34x devices does not support all features. The + * prescaler is limited and there is no support for sending a RS232 + * break condition. A read failure when trying to set up the latter is + * used to detect these devices. + */ + r = usb_control_msg_recv(udev, 0, CH341_REQ_READ_REG, + USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, + CH341_REG_BREAK, 0, &buffer, size, + DEFAULT_TIMEOUT, GFP_KERNEL); + if (r == -EPIPE) { + dev_info(&port->dev, "break control not supported, using simulated break\n"); + quirks = CH341_QUIRK_LIMITED_PRESCALER | CH341_QUIRK_SIMULATE_BREAK; + r = 0; + } else if (r) { + dev_err(&port->dev, "failed to read break control: %d\n", r); + } + + if (quirks) { + dev_dbg(&port->dev, "enabling quirk flags: 0x%02lx\n", quirks); + priv->quirks |= quirks; + } + + 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; + /* + * Some CH340 devices appear unable to change the initial LCR + * settings, so set a sane 8N1 default. + */ + priv->lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8; + + r = ch341_configure(port->serial->dev, priv); + if (r < 0) + goto error; + + usb_set_serial_port_data(port, priv); + + r = ch341_detect_quirks(port); + if (r < 0) + goto error; + + return 0; + +error: kfree(priv); + return r; +} + +static void ch341_port_remove(struct usb_serial_port *port) +{ + struct ch341_private *priv; + + priv = usb_get_serial_port_data(port); + kfree(priv); +} + +static int ch341_carrier_raised(struct usb_serial_port *port) +{ + struct ch341_private *priv = usb_get_serial_port_data(port); + if (priv->msr & 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->mcr |= CH341_BIT_RTS | CH341_BIT_DTR; + else + priv->mcr &= ~(CH341_BIT_RTS | CH341_BIT_DTR); + spin_unlock_irqrestore(&priv->lock, flags); + ch341_set_handshake(port->serial->dev, priv->mcr); +} + +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 ch341_private *priv = usb_get_serial_port_data(port); + int r; + + 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); + return r; + } + + r = ch341_get_status(port->serial->dev, priv); + if (r < 0) { + dev_err(&port->dev, "failed to read modem status: %d\n", r); + goto err_kill_interrupt_urb; + } + + r = usb_serial_generic_open(tty, port); + if (r) + goto err_kill_interrupt_urb; + + return 0; + +err_kill_interrupt_urb: + usb_kill_urb(port->interrupt_in_urb); + + 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, + const struct ktermios *old_termios) +{ + struct ch341_private *priv = usb_get_serial_port_data(port); + unsigned baud_rate; + unsigned long flags; + u8 lcr; + int r; + + /* redundant changes may cause the chip to lose bytes */ + if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios)) + return; + + baud_rate = tty_get_baud_rate(tty); + + lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX; + + switch (C_CSIZE(tty)) { + case CS5: + lcr |= CH341_LCR_CS5; + break; + case CS6: + lcr |= CH341_LCR_CS6; + break; + case CS7: + lcr |= CH341_LCR_CS7; + break; + case CS8: + lcr |= CH341_LCR_CS8; + break; + } + + if (C_PARENB(tty)) { + lcr |= CH341_LCR_ENABLE_PAR; + if (C_PARODD(tty) == 0) + lcr |= CH341_LCR_PAR_EVEN; + if (C_CMSPAR(tty)) + lcr |= CH341_LCR_MARK_SPACE; + } + + if (C_CSTOPB(tty)) + lcr |= CH341_LCR_STOP_BITS_2; + + if (baud_rate) { + priv->baud_rate = baud_rate; + + r = ch341_set_baudrate_lcr(port->serial->dev, priv, + priv->baud_rate, lcr); + if (r < 0 && old_termios) { + priv->baud_rate = tty_termios_baud_rate(old_termios); + tty_termios_copy_hw(&tty->termios, old_termios); + } else if (r == 0) { + priv->lcr = lcr; + } + } + + spin_lock_irqsave(&priv->lock, flags); + if (C_BAUD(tty) == B0) + priv->mcr &= ~(CH341_BIT_DTR | CH341_BIT_RTS); + else if (old_termios && (old_termios->c_cflag & CBAUD) == B0) + priv->mcr |= (CH341_BIT_DTR | CH341_BIT_RTS); + spin_unlock_irqrestore(&priv->lock, flags); + + ch341_set_handshake(port->serial->dev, priv->mcr); +} + +/* + * A subset of all CH34x devices don't support a real break condition and + * reading CH341_REG_BREAK fails (see also ch341_detect_quirks). This function + * simulates a break condition by lowering the baud rate to the minimum + * supported by the hardware upon enabling the break condition and sending + * a NUL byte. + * + * Incoming data is corrupted while the break condition is being simulated. + * + * Normally the duration of the break condition can be controlled individually + * by userspace using TIOCSBRK and TIOCCBRK or by passing an argument to + * TCSBRKP. Due to how the simulation is implemented the duration can't be + * controlled. The duration is always about (1s / 46bd * 9bit) = 196ms. + */ +static void ch341_simulate_break(struct tty_struct *tty, int break_state) +{ + struct usb_serial_port *port = tty->driver_data; + struct ch341_private *priv = usb_get_serial_port_data(port); + unsigned long now, delay; + int r; + + if (break_state != 0) { + dev_dbg(&port->dev, "enter break state requested\n"); + + r = ch341_set_baudrate_lcr(port->serial->dev, priv, + CH341_MIN_BPS, + CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8); + if (r < 0) { + dev_err(&port->dev, + "failed to change baud rate to %u: %d\n", + CH341_MIN_BPS, r); + goto restore; + } + + r = tty_put_char(tty, '\0'); + if (r < 0) { + dev_err(&port->dev, + "failed to write NUL byte for simulated break condition: %d\n", + r); + goto restore; + } + + /* + * Compute expected transmission duration including safety + * margin. The original baud rate is only restored after the + * computed point in time. + * + * 11 bits = 1 start, 8 data, 1 stop, 1 margin + */ + priv->break_end = jiffies + (11 * HZ / CH341_MIN_BPS); + + return; + } + + dev_dbg(&port->dev, "leave break state requested\n"); + + now = jiffies; + + if (time_before(now, priv->break_end)) { + /* Wait until NUL byte is written */ + delay = priv->break_end - now; + dev_dbg(&port->dev, + "wait %d ms while transmitting NUL byte at %u baud\n", + jiffies_to_msecs(delay), CH341_MIN_BPS); + schedule_timeout_interruptible(delay); + } + +restore: + /* Restore original baud rate */ + r = ch341_set_baudrate_lcr(port->serial->dev, priv, priv->baud_rate, + priv->lcr); + if (r < 0) + dev_err(&port->dev, + "restoring original baud rate of %u failed: %d\n", + priv->baud_rate, r); +} + +static void ch341_break_ctl(struct tty_struct *tty, int break_state) +{ + const uint16_t ch341_break_reg = + ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK; + struct usb_serial_port *port = tty->driver_data; + struct ch341_private *priv = usb_get_serial_port_data(port); + int r; + uint16_t reg_contents; + uint8_t break_reg[2]; + + if (priv->quirks & CH341_QUIRK_SIMULATE_BREAK) { + ch341_simulate_break(tty, break_state); + return; + } + + r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, + ch341_break_reg, 0, break_reg, 2); + if (r) { + dev_err(&port->dev, "%s - USB control read error (%d)\n", + __func__, r); + return; + } + 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; + break_reg[1] &= ~CH341_LCR_ENABLE_TX; + } else { + dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__); + break_reg[0] |= CH341_NBREAK_BITS; + break_reg[1] |= CH341_LCR_ENABLE_TX; + } + 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); +} + +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->mcr |= CH341_BIT_RTS; + if (set & TIOCM_DTR) + priv->mcr |= CH341_BIT_DTR; + if (clear & TIOCM_RTS) + priv->mcr &= ~CH341_BIT_RTS; + if (clear & TIOCM_DTR) + priv->mcr &= ~CH341_BIT_DTR; + control = priv->mcr; + spin_unlock_irqrestore(&priv->lock, flags); + + return ch341_set_handshake(port->serial->dev, control); +} + +static void ch341_update_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->msr; + priv->msr = 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_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->mcr; + status = priv->msr; + 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 usb_serial_port *port = serial->port[0]; + struct ch341_private *priv; + int ret; + + priv = usb_get_serial_port_data(port); + if (!priv) + return 0; + + /* reconfigure ch341 serial port after bus-reset */ + ch341_configure(serial->dev, priv); + + if (tty_port_initialized(&port->port)) { + ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO); + if (ret) { + dev_err(&port->dev, "failed to submit interrupt urb: %d\n", + ret); + return ret; + } + + ret = ch341_get_status(port->serial->dev, priv); + if (ret < 0) { + dev_err(&port->dev, "failed to read modem status: %d\n", + ret); + } + } + + return usb_serial_generic_resume(serial); +} + +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 v2"); |