Commit 9034389c authored by Konstantin Shkolnyy's avatar Konstantin Shkolnyy Committed by Johan Hovold
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USB: serial: cp210x: get rid of magic numbers in CRTSCTS flag code 



Replaced magic numbers used in the CRTSCTS flag code with symbolic names
from the chip specification.

Signed-off-by: default avatarKonstantin Shkolnyy <konstantin.shkolnyy@gmail.com>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent a377f9e9

drivers/usb/serial/cp210x.c

+84 −25
Original line number Diff line number Diff line
@@ -327,6 +327,42 @@ struct cp210x_comm_status { 
 */

#define PURGE_ALL		0x000f



/* CP210X_GET_FLOW/CP210X_SET_FLOW read/write these 0x10 bytes */

struct cp210x_flow_ctl {

	__le32	ulControlHandshake;

	__le32	ulFlowReplace;

	__le32	ulXonLimit;

	__le32	ulXoffLimit;

} __packed;



/* cp210x_flow_ctl::ulControlHandshake */

#define CP210X_SERIAL_DTR_MASK		GENMASK(1, 0)

#define CP210X_SERIAL_DTR_SHIFT(_mode)	(_mode)

#define CP210X_SERIAL_CTS_HANDSHAKE	BIT(3)

#define CP210X_SERIAL_DSR_HANDSHAKE	BIT(4)

#define CP210X_SERIAL_DCD_HANDSHAKE	BIT(5)

#define CP210X_SERIAL_DSR_SENSITIVITY	BIT(6)



/* values for cp210x_flow_ctl::ulControlHandshake::CP210X_SERIAL_DTR_MASK */

#define CP210X_SERIAL_DTR_INACTIVE	0

#define CP210X_SERIAL_DTR_ACTIVE	1

#define CP210X_SERIAL_DTR_FLOW_CTL	2



/* cp210x_flow_ctl::ulFlowReplace */

#define CP210X_SERIAL_AUTO_TRANSMIT	BIT(0)

#define CP210X_SERIAL_AUTO_RECEIVE	BIT(1)

#define CP210X_SERIAL_ERROR_CHAR	BIT(2)

#define CP210X_SERIAL_NULL_STRIPPING	BIT(3)

#define CP210X_SERIAL_BREAK_CHAR	BIT(4)

#define CP210X_SERIAL_RTS_MASK		GENMASK(7, 6)

#define CP210X_SERIAL_RTS_SHIFT(_mode)	(_mode << 6)

#define CP210X_SERIAL_XOFF_CONTINUE	BIT(31)



/* values for cp210x_flow_ctl::ulFlowReplace::CP210X_SERIAL_RTS_MASK */

#define CP210X_SERIAL_RTS_INACTIVE	0

#define CP210X_SERIAL_RTS_ACTIVE	1

#define CP210X_SERIAL_RTS_FLOW_CTL	2



/*

 * Reads a variable-sized block of CP210X_ registers, identified by req.

 * Returns data into buf in native USB byte order.
@@ -694,9 +730,10 @@ static void cp210x_get_termios_port(struct usb_serial_port *port, 
{

	struct device *dev = &port->dev;

	unsigned int cflag;

	u8 modem_ctl[16];

	struct cp210x_flow_ctl flow_ctl;

	u32 baud;

	u16 bits;

	u32 ctl_hs;



	cp210x_read_u32_reg(port, CP210X_GET_BAUDRATE, &baud);
@@ -792,9 +829,10 @@ static void cp210x_get_termios_port(struct usb_serial_port *port, 
		break;

	}



	cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,

			sizeof(modem_ctl));

	if (modem_ctl[0] & 0x08) {

	cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,

			sizeof(flow_ctl));

	ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake);

	if (ctl_hs & CP210X_SERIAL_CTS_HANDSHAKE) {

		dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);

		cflag |= CRTSCTS;

	} else {
@@ -863,7 +901,6 @@ static void cp210x_set_termios(struct tty_struct *tty, 
	struct device *dev = &port->dev;

	unsigned int cflag, old_cflag;

	u16 bits;

	u8 modem_ctl[16];



	cflag = tty->termios.c_cflag;

	old_cflag = old_termios->c_cflag;
@@ -947,34 +984,56 @@ static void cp210x_set_termios(struct tty_struct *tty, 
	}



	if ((cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {

		struct cp210x_flow_ctl flow_ctl;

		u32 ctl_hs;

		u32 flow_repl;



		/* Only bytes 0, 4 and 7 out of first 8 have functional bits */



		cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,

				sizeof(modem_ctl));

		dev_dbg(dev, "%s - read modem controls = %02x .. .. .. %02x .. .. %02x\n",

			__func__, modem_ctl[0], modem_ctl[4], modem_ctl[7]);

		cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,

				sizeof(flow_ctl));

		ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake);

		flow_repl = le32_to_cpu(flow_ctl.ulFlowReplace);

		dev_dbg(dev, "%s - read ulControlHandshake=0x%08x, ulFlowReplace=0x%08x\n",

				__func__, ctl_hs, flow_repl);



		if (cflag & CRTSCTS) {

			modem_ctl[0] &= ~0x7B;

			modem_ctl[0] |= 0x09;

			modem_ctl[4] = 0x80;

			/* FIXME - why clear reserved bits just read? */

			modem_ctl[5] = 0;

			modem_ctl[6] = 0;

			modem_ctl[7] = 0;

			ctl_hs &= ~(CP210X_SERIAL_DTR_MASK |

					CP210X_SERIAL_CTS_HANDSHAKE |

					CP210X_SERIAL_DSR_HANDSHAKE |

					CP210X_SERIAL_DCD_HANDSHAKE |

					CP210X_SERIAL_DSR_SENSITIVITY);

			ctl_hs |= CP210X_SERIAL_DTR_SHIFT(

					CP210X_SERIAL_DTR_ACTIVE);

			ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE;

			/*

			 * FIXME: Why clear bits unrelated to flow control.

			 * Why clear CP210X_SERIAL_XOFF_CONTINUE which is

			 * never set

			 */

			flow_repl = 0;

			flow_repl |= CP210X_SERIAL_RTS_SHIFT(

					CP210X_SERIAL_RTS_FLOW_CTL);

			dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);

		} else {

			modem_ctl[0] &= ~0x7B;

			modem_ctl[0] |= 0x01;

			modem_ctl[4] = 0x40;

			ctl_hs &= ~(CP210X_SERIAL_DTR_MASK |

					CP210X_SERIAL_CTS_HANDSHAKE |

					CP210X_SERIAL_DSR_HANDSHAKE |

					CP210X_SERIAL_DCD_HANDSHAKE |

					CP210X_SERIAL_DSR_SENSITIVITY);

			ctl_hs |= CP210X_SERIAL_DTR_SHIFT(

					CP210X_SERIAL_DTR_ACTIVE);

			/* FIXME: Why clear bits unrelated to flow control */

			flow_repl &= 0xffffff00;

			flow_repl |= CP210X_SERIAL_RTS_SHIFT(

					CP210X_SERIAL_RTS_ACTIVE);

			dev_dbg(dev, "%s - flow control = NONE\n", __func__);

		}



		dev_dbg(dev, "%s - write modem controls = %02x .. .. .. %02x .. .. %02x\n",

			__func__, modem_ctl[0], modem_ctl[4], modem_ctl[7]);

		cp210x_write_reg_block(port, CP210X_SET_FLOW, modem_ctl,

				sizeof(modem_ctl));

		dev_dbg(dev, "%s - write ulControlHandshake=0x%08x, ulFlowReplace=0x%08x\n",

				__func__, ctl_hs, flow_repl);

		flow_ctl.ulControlHandshake = cpu_to_le32(ctl_hs);

		flow_ctl.ulFlowReplace = cpu_to_le32(flow_repl);

		cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl,

				sizeof(flow_ctl));

	}



}