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USB: serial: ch341: add register and USB request definitions
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No functional changes, this just gives names to some registers and USB
requests based on Grigori Goronzy's work and WinChipTech's Linux driver
(which reassuringly agree), then uses them in place of magic numbers.
This also renames the misnamed BREAK2 register (actually UART config)

Signed-off-by: Aidan Thornton <makosoft@gmail.com>
Reviewed-by: Grigori Goronzy <greg@chown.ath.cx>
Signed-off-by: Johan Hovold <johan@kernel.org>
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Aidan Thornton authored and Johan Hovold committed Oct 24, 2016
1 parent 6b7271d commit 6fde8d2
Showing 1 changed file with 32 additions and 19 deletions.
51 changes: 32 additions & 19 deletions drivers/usb/serial/ch341.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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) },
Expand Down Expand Up @@ -144,16 +157,16 @@ static int ch341_set_baudrate(struct usb_device *dev,
a = (factor & 0xff00) | divisor;
b = factor & 0xff;

r = ch341_control_out(dev, 0x9a, 0x1312, a);
r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a);
if (!r)
r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x0f2c, b);

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)
Expand All @@ -167,7 +180,7 @@ 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;

Expand Down Expand Up @@ -197,11 +210,11 @@ 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;

r = ch341_control_out(dev, 0xa1, 0, 0);
r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
if (r < 0)
goto out;

Expand All @@ -210,11 +223,11 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
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;

Expand All @@ -223,7 +236,7 @@ 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);
r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0x501f, 0xd90a);
if (r < 0)
goto out;

Expand Down Expand Up @@ -370,7 +383,7 @@ static void ch341_set_termios(struct tty_struct *tty,
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;
Expand All @@ -391,12 +404,12 @@ 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]);
Expand Down

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