summaryrefslogtreecommitdiffstats
path: root/drivers/usb/serial/ch341.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/usb/serial/ch341.c')
-rw-r--r--drivers/usb/serial/ch341.c857
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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-18 13:28:17 +0000