1 files changed, 75 insertions, 38 deletions

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index f139488d0816..2597b83a8ae2 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -61,13 +61,26 @@
  * 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_REG_BREAK1       0x05
-#define CH341_REG_BREAK2       0x18
-#define CH341_NBREAK_BITS_REG1 0x01
-#define CH341_NBREAK_BITS_REG2 0x40
-
+#define CH341_REQ_SERIAL_INIT  0xA1
+#define CH341_REQ_MODEM_CTRL   0xA4
+
+#define CH341_REG_BREAK        0x05
+#define CH341_REG_LCR          0x18
+#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
 
 static const struct usb_device_id id_table[] = {
 	{ USB_DEVICE(0x4348, 0x5523) },
@@ -119,10 +132,10 @@ static int ch341_control_in(struct usb_device *dev,
 	return r;
 }
 
-static int ch341_set_baudrate(struct usb_device *dev,
-			      struct ch341_private *priv)
+static int ch341_init_set_baudrate(struct usb_device *dev,
+				   struct ch341_private *priv, unsigned ctrl)
 {
-	short a, b;
+	short a;
 	int r;
 	unsigned long factor;
 	short divisor;
@@ -142,18 +155,17 @@ static int ch341_set_baudrate(struct usb_device *dev,
 
 	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);
+	/* 0x9c is "enable SFR_UART Control register and timer" */
+	r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT,
+			      0x9c | (ctrl << 8), a | 0x80);
 
 	return r;
 }
 
 static int ch341_set_handshake(struct usb_device *dev, u8 control)
 {
-	return ch341_control_out(dev, 0xa4, ~control, 0);
+	return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
 }
 
 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
@@ -167,7 +179,7 @@ static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
 	if (!buffer)
 		return -ENOMEM;
 
-	r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
+	r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
 	if (r < 0)
 		goto out;
 
@@ -197,24 +209,21 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 		return -ENOMEM;
 
 	/* expect two bytes 0x27 0x00 */
-	r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
+	r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
 	if (r < 0)
 		goto out;
+	dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
 
-	r = ch341_control_out(dev, 0xa1, 0, 0);
-	if (r < 0)
-		goto out;
-
-	r = ch341_set_baudrate(dev, priv);
+	r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
 	if (r < 0)
 		goto out;
 
 	/* expect two bytes 0x56 0x00 */
-	r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
+	r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x2518, 0, buffer, size);
 	if (r < 0)
 		goto out;
 
-	r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
+	r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, 0x0050);
 	if (r < 0)
 		goto out;
 
@@ -223,11 +232,7 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *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);
+	r = ch341_init_set_baudrate(dev, priv, 0);
 	if (r < 0)
 		goto out;
 
@@ -342,16 +347,53 @@ static void ch341_set_termios(struct tty_struct *tty,
 	struct ch341_private *priv = usb_get_serial_port_data(port);
 	unsigned baud_rate;
 	unsigned long flags;
+	unsigned char ctrl;
+	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);
 
 	priv->baud_rate = baud_rate;
+	ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
+
+	switch (C_CSIZE(tty)) {
+	case CS5:
+		ctrl |= CH341_LCR_CS5;
+		break;
+	case CS6:
+		ctrl |= CH341_LCR_CS6;
+		break;
+	case CS7:
+		ctrl |= CH341_LCR_CS7;
+		break;
+	case CS8:
+		ctrl |= CH341_LCR_CS8;
+		break;
+	}
+
+	if (C_PARENB(tty)) {
+		ctrl |= CH341_LCR_ENABLE_PAR;
+		if (C_PARODD(tty) == 0)
+			ctrl |= CH341_LCR_PAR_EVEN;
+		if (C_CMSPAR(tty))
+			ctrl |= CH341_LCR_MARK_SPACE;
+	}
+
+	if (C_CSTOPB(tty))
+		ctrl |= CH341_LCR_STOP_BITS_2;
 
 	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);
+		r = ch341_init_set_baudrate(port->serial->dev, priv, ctrl);
+		if (r < 0 && old_termios) {
+			priv->baud_rate = tty_termios_baud_rate(old_termios);
+			tty_termios_copy_hw(&tty->termios, old_termios);
+		}
 	} else {
 		spin_lock_irqsave(&priv->lock, flags);
 		priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
@@ -360,17 +402,12 @@ static void ch341_set_termios(struct tty_struct *tty,
 
 	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 =
-			((uint16_t) CH341_REG_BREAK2 << 8) | CH341_REG_BREAK1;
+			((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
 	struct usb_serial_port *port = tty->driver_data;
 	int r;
 	uint16_t reg_contents;
@@ -391,12 +428,12 @@ static void ch341_break_ctl(struct tty_struct *tty, int break_state)
 		__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;
+		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_REG1;
-		break_reg[1] |= CH341_NBREAK_BITS_REG2;
+		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]);